PackLite - Questions and More Bass Talk

It would seem that many if not most people who are into music, like bass, and lots of it. I know that I have been guilty of boosting my voice and guitar to unnatural levels from time to time. The PAS however is like a tattle tale, it will remind you that what you are doing is unnatural and, gives me guilt feelings for trying to be bigger than life.

Since buying the PAS I have changed my perspective a little, and enjoy working with a very natural sound, but still for certain songs or moods will boost the lows for effect.

There are times, still, when I miss the 2 MB4's I was using before the PAS or the bigger subs on house systems where I sometimes play.

So my questions are; Can a solo act, primarily acoustic guitar and male vocal take advantage of this new addition?

If EQ'ed to sound natural will there be more of the low end present in the mix?

Would it have the effect of filling a room with a bigger, but still natural sound?

In case you are wondering, yes, I have a little trouble understanding the concept of being able to play louder and still maintain the same spectral balance, when maybe what I am after is changing the spectral balance while maintaining a lower or comfortable volume level.

Would be interested in seeing comments from anyone who can make sense of what I just said. Smile

What about the testers, ST, did you try a 4 B1 setup with acoustic guitar and vocal?

Oldghm

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Just my opinion, but I don't think the A1 was developed with guys like you in mind, Oldghm. Maybe Scott McKenna, who wants that big boom when he "hits" the guitar, or maybe guys with the Porchboard who feel they need more. It seems to be more aimed at bass/drum players, or anyone who can use an extra, very sweet amp for whatever reason.

I certainly hope that acoustic solo players aren't feeling left out or let down by this product, I am thrilled with it.
Hi Oldghm,

I tried to dream up different scenarios and applications including 4 B1s with Acoustic Guitar and Vocal.

One of the interesting observations - regardless of the sound source was there was not a stunning, smack you in the face, ruffle the pants or change-your-gender, type difference. Or rather, it was only really apparent (at least to me) when you really had the System running quite loud - and under circumstances where you may have felt a little more bottom end was required.

So - a couple more-concrete scenarios where 4 x B1 seemed a better solution than 2 x B1 ...

  • If you felt that the bass was good, clean, present - whatever you like about bass - but that it seemed to run out of steam at some distance from the stage. What may have been contributing to the perception was the way the L1 just keeps throwing and throwing and throwing. Adding a couple of B1s with the A1 just seems to let you keep up better with the L1.

  • Outside where you don't have the benefit of walls to help the bass 'travel' to the audience.



I think that if you have felt that the double B1 system needed *more* power - when you were already running the System ***loud*** then your perception would be that 4 B1s keep up with the L1 better than 2. But - if you are not running loud, for Acoustic Guitar and Vocal, the difference is pretty subtle. I think the experience of it is similar to the difference going from 1 B1 to 2, but less apparent unless you're really pushing things.

Now when you to instruments and sources lower than the Acoustic Guitar (or most voices), I think you would have a much more profound sense of the differences.
OK At-Bose-Guys,

I have never claimed to have a full and complete understanding of the bass thing, so I've been doing some reading from a while back and ran across something from Hilmar that might help me understand how and why you can go from 1 B1 to 4 B1's and not hear a major difference from a vocal or acoustic guitar that really just goes down to 80hz or so.

Hilmar mentioned the crossover being "smart". It changes as more B1's are added.

Please correct me if I'm wrong, but, can we assume that the crossover drops, lower and lower, as B1's are added? Thus as you add B1's less and less of the acoustic guitar bottom end is actually going to the B1's.

Is it possible that with 4 or more B1's we actually go backwards to the point that nearly all of the acoustic guitar is in the L1? Almost as if we didn't have a B1 attached.

What is the crossover when using the PS1 / L1 with 2B1's and the PackLite with 2 B1's, for a total of 4 B1's?

Is there any way to trick the "smart" crossover, and still get good results from the B1's?

Is the L1 less, just as, or more, efficient at dispersing those frequencies between 110 hz and 180 hz?

My perception is that it is less, but I am often fooled by what comes from where.

Is there an easy to understand explanation for this design, other than to maintain a pre determined spectral balance.

Oldghm
Hi Oldghm,
Hopefully I can help answer some of your questions. Before doing that, allow me to explain the design and intention.

In keeping with the premise that musicians should worry less about the gear, the system was designed to be smart about bass management. We did not want you the musician to be tasked with having to re-EQ the system depending on how much bass you decided to use. So, whether you go from zero B1s to 1 B1, to 2 B1, to 4 B1s, the system is making changes to the crossover and level to compensate the fact that you have added (or taken away) bass modules.

We did this so that the system maintains a spectral balance as best as possible so that you didn't have to manage the difference yourself. Of course with zero B1s we are not able to maintain a the wide band down to 40 Hz. The L1 does it's best down to 110 Hz. By adding B1s however the system simply shifts the crossover to 180 Hz, applies active EQ to the B1s and will attentuate the output depending on how many B1s you decide to use. As you add amplification and loudspeakers we gain more overall output in the bass frequencies. To maintain that spectral balance, we simple reduce the signal going out to the B1s (or PackLite amplifier) so that you don't need to fuss with the remote tone controls or have special presets for how many B1s (yikes!). The same tone that you found with presets and tone control adjustments with lower levels (less B1s) is now available at higher levels in those regions (more B1s).

This however is not to say that the L1 will get louder. Bass-heavy instruments like bass guitar and kick drum had a good tone at lower levels with, let's say, a single B1. Unfortunetely, these players have probably found that if they needed more punch in larger rooms that a single B1 only went so far and that the L1 continued to get louder. Two B1s give you the ability to substatially get louder in the bass region- more headroom with two B1s. In expansion, 4 B1s give bass players even more headroom to play. (I believe 4 B1s will satisfy most bass players in a variety of larger venues, we've tried 8 B1s and it just seems way too much)

Said another way: As soon as you plug in a PackLite and two B1s, you will not feel a difference in sound. It was designed to perform like this! What you will find is that you NOW have the ability to change your tone. Go ahead, grab the remote tone knobs, change the preset if you want- you now can tailor your bass-heavy instruments in a way that was not so audible before with less B1s.



Originally posted by Oldghm:
quote:
OK At-Bose-Guys,

I have never claimed to have a full and complete understanding of the bass thing, so I've been doing some reading from a while back and ran across something from Hilmar that might help me understand how and why you can go from 1 B1 to 4 B1's and not hear a major difference from a vocal or acoustic guitar that really just goes down to 80hz or so.

Yes, that's correct. Fundamental frequencies of those instruments are not present below 80Hz. That is why you'll find 80Hz high-pass switches on so many mixers and microphones- it allows you to trash those unwanted frequencies. In a performance enviornment it halts the pickup of unwanted bass frequencies (instruments, HVAC units, crowd rumble) from bleeding into your mics.

quote:
Hilmar mentioned the crossover being "smart". It changes as more B1's are added.

That's right. The crossover critical frequency remains the same with one or more B1s added (or use of the Bass-Line OUT connector)- 180 Hz. The other end of the intellegence comes from knowing if you have 0, 1, 2, or 4 B1s connected and attenuating the signal where appropriate to compensate.

quote:
Please correct me if I'm wrong, but, can we assume that the crossover drops, lower and lower, as B1's are added? Thus as you add B1's less and less of the acoustic guitar bottom end is actually going to the B1's.

No, all bottom end (below 180Hz) is being routed to B1s always. The level out to bass modules will drop but only to balance the fact that more acoustic output is being gained by adding bass modules. By increasing the MASTER you'll see that all of that power is available to you, just in a balanced fashion.

quote:
Is it possible that with 4 or more B1's we actually go backwards to the point that nearly all of the acoustic guitar is in the L1? Almost as if we didn't have a B1 attached.

Never. Never! Smile


quote:
What is the crossover when using the PS1 / L1 with 2B1's and the PackLite with 2 B1's, for a total of 4 B1's?

The crossover point is 180Hz

quote:
Is there any way to trick the "smart" crossover, and still get good results from the B1's?

There is no way to change the crossover frequency point of the system.

quote:
Is the L1 less, just as, or more, efficient at dispersing those frequencies between 110 hz and 180 hz?

Hilmar can speak to dispersion patterns better than I can but it's my understanding that 110-180 Hz doesn't do a great job at being a cylindrical wavefront anyway. Considering that it's also in a range that's not perceptibly directional (bass), it was decided to route that down to the B1 that does a much better job reproducing those frequencies. As a listener, we have a hard time hearing where that range is coming from so to the B1 on the floor it goes.

quote:

My perception is that it is less, but I am often fooled by what comes from where.

Is there an easy to understand explanation for this design, other than to maintain a pre determined spectral balance.

I hope I helped! If not, let's keep the conversation going.
quote:
Please correct me if I'm wrong, but, can we assume that the crossover drops, lower and lower, as B1's are added? Thus as you add B1's less and less of the acoustic guitar bottom end is actually going to the B1's.

I think the key thing to communicate here is that adding a PackLite(tm) amp and more B1s adds more output when you need it.

Oldghm, the crossover does not change frequency location. It remains at 180 Hz. What I believe Hilmar was talking about is that the system has more low frequency output capability as you add B1s so the EQ adjusts accordingly.

This is a great topic of conversation and it is clearly something we've got to figure out with PackLite marketing materials. It's a complicated thing to communicate.

Here's my attempt to simplify what's going on.

Adding the PackLite(tm) Extended Bass Package (4 B1s total) gives you the ability to have more acoustic output from 180Hz down.

It does not change the spectral balance (acoustic output from 180Hz down) of the system until you reach a volume level that exceeds the capability of 2 B1s.

By the way, you can get more bass by turning the "Bass" knob on the R1 remote and change the spectral balance that you're asking the system to reproduce.

Clear as mud?

The challenge we have is that we, as musicians and speaker buyers, have been trained to think of buying things in bits. Need more bass, buy more bass speakers and you'll have it. That's because the stuff we buy is not designed to work together.

When an engineer gets to design and optimize the entire solution, they can really do some great things. One of which is make the most out of the output of an amp and a speaker cone working together. That's what the gang here did with the Power Stand and the B1 bass module. They work really well together.

Eventually, as you raise the volume, the acoustic output of the amp and speaker cone reaches its limit and the system says "all done", that's as much bass as I can throw. That's when adding more B1s and a PackLite amp will help ... when you've reached the limit.

It's a pretty hard thing to communicate. We know that a customer is going to be running 2 B1s, hook up a PackLite amp and 2 more B1s and say "hey, there's no noticeable change." and we'll say "yeah, isn't that cool?" to which a customer will say "huh??". Then we say, "well you've added headroom without changing the spectral balance of the system without touching a crossover knob, or an EQ ... just try that with any other speaker system out there" with a big, full of pride, grin on our face.

The customer might then say, "so why buy it?" to which we'll say, "now turn up and down and notice how great the system sounds at any volume without you having to touch any knobs ... it's like bringing Hilmar to your gig to run the volume and EQ controls for your band ... COOL huh?"

Hopefully, with your help we'll find the short way (or analogy) to describing this very cool benefit. Believe me, the engineering team worked hard to give you this benefit. It's real. It would have been WAY easier to develop a solution that was "slap an A1 & 2 more B1s on and boom, more bass; now everything sound good at one volume and muddy at another."

I hope that helps ... PLEASE, more questions. This is helping me a bunch.

Steve
Well I misquoted Hilmar, what he said was, "oops I forgot ... Crossover is actually 180hz, but it is inteligent crossover, i.e. it changes frequency and gain depending on how many B1s are attached."

Do a search for "oops I forgot" to read the thread.

So does it change frequency or not? If it does can you talk about it a little? What, where, how much?

If it doesn't can you reprimand Hilmar? Smile

Oldghm
quote:
Originally posted by Alan Steinberger:

Aren't they saying the following?
• The crossover changes from 110 to 180 Hz as soon as you add the first B1, but is unaffected by additional B1's.



I suppose that's one way to interpret it, My thought process was that there is not a crossover involved until The B1 is plugged in, engaging the crossover.

There is no need for a "crossover" if the L1 is all that is connected.

Oldghm
I believe that's correct, Alan. Here's how I understand it - The crossover will also kick in at 180Hz when a cable is plugged in to the bass line out jack (even if no B1's are connected at Amp 3 out). The B1 EQ curve is also a little tricky. The specialized B1 EQ will be applied when a Speakon cable is connected at Amp 3 out. If there are B1's connected to the system (via Amp 3 out) the B1 EQ will also be applied to the Bass Line Out signal. If NO Speakon is plugged in to Amp 3 out, the Bass Line Out will deliver a flat un-EQ'd 40-180Hz signal. So there are really 3 issues that the smart processor is dealing with - Crossover, EQ and Bass Sound Pressure Levels - constantly adjusting to "level" itself depending on configuration.

I've decided that the processor is smarter than me, and I will no longer try to out-think it...I'll just let it do what it does.
quote:
Originally posted by Oldghm:
There is no need for a "crossover" if the L1 is all that is connected.

With no B1's, crossover only in the sense that nothing below 110 is allowed access to the L1, but the full range signal is present at the individual line outs.

My understanding, anyway. But I haven't had any coffee yet...
A minor technicality... whether the crossover is actively imposing the 110 Hz on the L1, or if it's inactive, and the L1 speakers are getting a full range signal, but are only capable of producing to 110hz (which I believe is the case)... remains uncertain. Same results either way.

Oh, Hilmaaarrrr.
Ummmmm ... exactly! You guys got it.

Ohhhh Hilmaaarrrr, we don't send any sound below 110Hz to the system, right. Why waste that power when it won't create enough acoustic output. I'm 90% sure that's the case. That's how I'd do it if I knew how to create circuit boards but thank goodness for us all they don't allow me near electrical stuff. Mechanical, nooooo problem. Electrical, watchout.
Thanks Drumr, ST, Kyle, Steve, Alan, and JG for the response.

quote:
Originally posted by Kyle-at-Bose:

That's right. The crossover critical frequency remains the same with one or more B1s added (or use of the Bass-Line OUT connector)- 180 Hz. The other end of the intellegence comes from knowing if you have 0, 1, 2, or 4 B1s connected and attenuating the signal where appropriateto compensate.



Kyle,

Some numbers that correspond to the bold type might be helpful.

Alan and gittar-jonz,

It wouldn't surprise me if the PS1 has a filter of sorts to limit the L1 from recieving frequencies below 110 hz, to protect the transducers from damage, and I am certainly not knowledgeable enough to argue whether or not it is a "crossover".

ST,

change-your-gender, now that's a powerful system, I don't think I have ever personally seen one, but I have a couple of friends that might have got too close to one a couple of times. Heck, I cry when I watch Pretty Woman, maybe I got too close and didn't know it.

Drumr,

Not feeling left out, just don't have a good excuse to send anymore money up to the Mountain. Have you seen a group picture of those guys? Cliff's the only one it appears is gettin enough to eat.

Oldghm
Ok, I have mentioned before that I have used subs, 15' or larger for about 27 or 28 years now. I like to think that I've done this because it made me sound better, and hopefully natural.

Occasionally when we talk about bass and acoustic guitar, someone will mention "fundamental" frequency. And most of us know by now that the acoustic guitar low E is about 80 hz, 78 I think, if you are right in tune, but I hardly ever am.

It also is mentioned occasionally that instruments will produce harmonics above the fundamental fairly easily but not so much below the fundamental.

If we take 15 Tele's and play each of them acoustically, (without amp) they will all sound about the same.

If we take 15, D size, acoustic guitars, even the same make and model, there will be more noticable differences, and if one is lucky there might be one great standout.

With some of these thoughts in mind I decided to run a simple set of experiments with a 000 Martin, with LR Baggs Ribbon Transducer active, a D-18GE Martin, with LR Baggs ibeam active, a Rane real time analyzer w/reference mic and the Bose Personalized Amplification System w/ 2 B1's.

With the Rane set to a sensitivity of 100 db, I played the guitars acoustically about 18 inches from the mic. (about the same distance as my ears are from the guitar)

I tried to strum the instruments as if I were playing a tune where I wanted to accentuate the low end, but not beat too hard or create percussive noises, I really wanted to measure only the string and resonant sound if possible.

Both guitars easily produced the low fundamental, the D-18, which I have mentioned before is a bassy instrument easily produced 63 hz.

I lowered the Rane sensitivity to 75 db, and tried again, both instruments indicated 50hz, and the D-18 easily lit up the 40hz LED.

Then I plugged the guitars directly into the PS1, with preset 00, and tone controls set flat. With the Rane set back at 100 db about 2 feet in front of the L1 / B1's, 40 hz was no problem for either guitar.

I was somewhat surprised that the 000 with Ribbon Transducer showed a wider, bolder, bass response than the D-18 with ibeam but, interestingly in real life playing situations is never a low feedback problem even without notch filters or sound hole dampening. I am guessing the smaller top, thinner body, doesn't produce or respond to those problem resonances as a D size guitar might.

I might add that at the time I installed the Ribbon transducer I was told by the Baggs rep it was the bassiest of the then available Baggs pickups.

So, what is my point?

Acoustic guitars, because much of their tone comes from the resonances of the wood, produce a wider spectrum of sound, that goes much lower than the fundamental. Because as players we not only hear but also feel those frequencies, natural sound includes what the sub is doing.

To be able to produce those low tones in a natural proportion to the guitar, but at a level where an audience can appreciate them should be the desire of everyone playing an acoustic instrument.

Comments?

Oldghm
Well I am a little disappointed no one wants to talk about this. I must be the only one who just can't grasp the concept of more is not more unless you turn it up.

quote:
Originally posted by Kyle-at-Bose:

No, all bottom end (below 180Hz) is being routed to B1s always. The level out to bass modules will drop but only to balance the fact that more acoustic output is being gained by adding bass modules. By increasing the MASTER you'll see that all of that power is available to you, just in a balanced fashion.



Kyle,

If I understand this statement correctly, as we add bass modules the system adjusts the output, reducing the bass in some proportion, to the setting of the MASTER control. Then we can get back what we lost and more by turning up the MASTER............ which doesn't make sense to me so let me ask a question in a differnt manner........

The "more acoustic output" that the system is adjusting for, can it be measured in air movement? If not, what do you mean by acoustic output in this context?

Or in other words, .......... If one Does Not move the MASTER volume, and changes from 2 B1's, to the PackLite and 2 more B1's for a total of 4, will the system move more air at the same or similar percieved volume as 2 B1's? Or, (same question, different words) Will we get greater coverage at the same percieved volume?

The adjustment that takes place as B1's are added, is it best described as gain, volume or tone? If Hilmar would talk about his statement that I quoted earlier, it might answer this question.

Am I wrong in thinking of coverage and volume as two different things?

I like to "think" that it is better to cover a room with a comfortable volume than to crank up too small a system to try to cover a space. I am not sure that describes what is actually going on when I have that perception.

So what I would like, is to be able to adjust my sound for my perception of "natural" but have that sound (the bass part) cover a larger area without boosting the bass control, or sustantially changing the volume in the venues I would normally play in. I would like to be able to make 2500 sq. feet or so inside sound and feel like 400 sq. feet. To me it seems like the L1 does the job but 2 B1's aren't enough for that same warm cozy feeling at the far reaches of a bigger room.

I'm not getting any smarter on my own, help me out!

Oldghm
quote:
Originally posted by Oldghm:
I'm not getting any smarter on my own, help me out!

Oldghm


I have been thinking about bass issues as well. I don't think I can help you out too much on your concerns, but I think I can complicate you life even more. Just what you wanted, right?

First, from what I can tell, what Bose has done with the A1/B1 option is increase bass headroom. It sounds just the same until a BIG BASS requirement comes along, and then it can keep up with the demand, instead of wimping out. We see the odd post which complains about the system "limiting" or "clipping", and I believe those folks have probably used up all 250 bass watts, even though the L1 is still happy as a clam.

I hereby move that Bose send oldghm an A1 and two B1s for him to assess and report back to the group.

Now, your latest post starts to talk about the bass out in the venue. This is where it gets sticky, not just for the PAS, but for everything, although what I am going to talk about is probably exacerbated with the Cylindrical Radiator. These issues have been touch on in a couple of other threads, but it seems a good time to drag them out again.

Just because two tones are of an equal intensity does not mean that they are of an equal loudness. It depends on the frequency. Our ears are most sensitive around 4 kHz, where all those articulation sounds such as "t" and "s" etc. generate their energy. Any tone lower or higher than 4 k will be perceived as quieter if it is the same intensity. In fact, the hearing scientists have invented a term to deal with this, the phon. Instead of referencing 4 kHz, the phon is referenced to 1 kHz, because so many audio measurements are made there (loudspeaker impedance and a single number reverberation time, for example). So, at 1 kHz, 60 dB SPL is 60 phon. However, at some other frequency, say 100 Hz, it takes about 68 dB SPL to sound as loud as 60 dB SPL at 1 kHz. However, we can talk about 60 phon at both frequencies, and mean that we perceive them as being of equal volume (which in itself is a little tricky. Play a high note and a low note on your instrument. Were they the same loudness?).

Does your brain hurt yet? Mine does.

But why am I going on about this? Well, consider the case where you, oldghm, are strumming a chord on your guitar, open E on the bottom, lets call it 80 Hz, and a high one way up the neck at about 1 kHz. You adjust your strum so that the low note and the high note sound the same loudness (say, 70 dB) to you as you monitor it on the PAS which happens to be 5 feet behind you. Now, here is where it all start to unravel. As we move into the audience area, to say 20', the 1 kHz note is now 64 dB (3 dB down at 10' and another 3 dB down at 20'), and so is the 80 Hz note. However, the 1 kHz note is at 64 phon, but the 80 Hz note is now at 54 phon. It gets even squirrelier if we are talking about a 4 kHz note near the top of the piano vs a 40 Hz note near the bottom. The 4 kHz note is behaving very nicely as a cylindrical wave, whereas the low note never was cylindrical and has always been decaying at 6 dB per doubling of distance. We're losing on the distance thing, and we're losing on the equal loudness curve thing as we move further and further into the audience.

How is your brain now?

Of course, this still isn't the whole story. If you are playing indoors, then at some distance away from the speaker, the reverberant field in the room matches the direct sound, so the volume does not appear to change. This varies with frequency, however, and varies from room to room as well. Variables include size, shape, construction technique, finishes, temperature, humidity, and the price of eggs in China. It is basically impossible to discern room behaviour in this regard without some sophisticated test equipment. Even if you know what it's doing, you probably have no opportunity to change it (except to be so popular that you fill it up with sabines... er, that is to say, patrons).

Could you pass the Aspirin, please?

I guess the point I am trying to make is that the performance of any system changes dramatically from note to note, and from venue to venue. It is a tribute to your perspicacity and curiosity that these things are troubling you. I wish I could help instead of just muck things up more. You asked for it! Smile
I think of the PAS with at least one B1 as being voiced for balanced frequency response across the full spectrum.

Practically my first post here concerned a soundcheck with a bass player who likes the darkest sound possible - virtually no finger or string noise. He found one B1 to be barely sufficient for a quiet setting, and two to be sort of adequate. He needed next to nothing from the L1, and more than was available from the B1's.

This is the sort of player who I think would benefit the most from adding the PackLite and two more B1's. I think of it as adding potential. The system will still be balanced with the knobs set to 12:00, but the players who want an exaggerated low end have more available sooner with a twist of the bass knob.
quote:
I hereby move that Bose send oldghm an A1 and two B1s for him to assess and report back to the group.


Oldghm,

What do you think? Wanna try it? I'm game if you are.

Steve

MTM,

PERFECT! That was a great post! You nailed it in a very simple to understand way. Nice job.

Here is yet ANOTHER way to think about PackLite(tm) amps, headroom and B1s:

Think of a B1 as a pint glass.

The B1 can handle/reproduce one pint of bass frequencies. When you fill it, you're out of headroom.

Two B1s can handle two pints of bass frequencies and 4 B1s can handle/reproduce ... you guessed it ... 4 pints of bass frequencies.

Okay, now let's say my music (could be kick drum, bass guitar, prerecorded, acoustic guitar, etc.) at 1/3 volume requires 1 pint of bass output. If I have 1 B1 the Power Stand will MAX it's output to handle the requested music and we have good spectral balance.

If we added a second B1 the system would say "AHhhhh ha!!!" and send each B1 1/2 a pint of music to get to the total 1 pint of output I need with my music at this volume. Still with me?

Now let's turn up my music. The single B1 has run out of "room", that is the pint glass is full. We added a second B1 to gain "headroom" and as we turn up we notice no change in spectral balance because the two B1s have "room left in the glass". Finally we hit a point with our music (which is bass heavy) requires 2 pints of bass output and our glasses run out of room for bass.

But we want more bass so in comes a PackLite(tm) extended bass package, now I have 4 pints of output capability. I start back at the same point, 1/3 volume on the master. I have 4 pints of B1s and need just 1 pint of bass output. Therefore the system says "Send everyone 0.25 pints of bass so that the total equals 1 pint". This is spectral balance as you change the volume (no body else does this that I know of -- you have to do it yourself every time you change your volume -- think about that for a second).

Now as you turn up to the point where you need 2 pints, each B1 takes on the work of producing 0.5 pints of bass and thus the total remains 2 pints. As we turn up to 3 and 4 pints we end up with a lot of bass output. Oh, and music is dynamic, so those pint glasses are constantly filling and draining, right? A bass note or kick drum goes like this, "gimme three pints NOW and then I'll drain to 2 pints quickly." Let me say that no oneshould have 4 pints of bass in one gig and then drive home. Smile Eek

So this is why we are SOOOOO excited about the PackLite extended bass package. Easy to carry, easy to setup and modular. AND we can keep your spectral balance right at any volume.

One last thing, this doesn't work for mandolin. Why? It's not a pint glass instrument. It's more of a shot glass instrument. It never needs more output (at any volume) than one B1 can fulfill. Does that make sense?

I hope that helped. Anyone thirsty? Drive carefully.

Steve
quote:
Originally posted by Steve-at-Bose:
Anyone thirsty?


I'll have a Red Brick Ale from the Atlanta Brewing Company, please, Steve. What the heck. Make it two!

Mike

PS Is your "Pint" explanation in the public domain? Also, would you care to share with the group your inspiration for this analogy?
Steve,

Well the mandolin analogy makes sense and in that respect the guiitar is really only a one pint instrument, but what if I want each of 4 corners to get the one pint?

The offer of a trial is interesting but I'm not sure it would help in the understanding of the concept. I have a gig, that might be appropriate for a test, in two weeks. Let me think on this and I'll send a PM on Monday.

If I am grasping the concept, using a 4 B1 setup with an acoustic guitar would be like a car salesman telling a "height challenged person" about head and leg room.

The PackLite and 2 B1's represent the "potential" of more bass output, but it first must be generated at the source or artificially exaggerated with the EQ. If I play the guitar very hard, or percussively what might overdrive the 1 or 2 B1 setup might not overdrive a 4 B1 setup.

If I am currently playing as loud as is neccessary in a particular venue, without any bass problems, then adding more B1's will not change the sound, or give me any benefit other than "potential".

MTM's post is not showing up here, did it slip away with the elusive bottom end I'm looking for? Smile

There is a theater in Lexington that hosts concerts from time to time, I have seen several great artists there, most recently Del McCoury. They almost always use the same sound company, and the main system is always the same whether it is a solo vocal and acoustic guitar or Merle Haggard with 13 pcs. They use 10 pro Turbosound cabinets, 3 way I believe. The sound is never loud, (for the shows I attend) It is as if you invited the artist into your living room.

I have seen the Woodsongs radio program recorded in the same space and they use 4 to 6, 12" powered Mackies, no where near the same output potential but one doesn't have a problem hearing, it's just not the same cozy feel as the bigger system. I suppose that is what I was hoping for, some kind of increased warmth by adding B1's.

Oldghm
quote:
Originally posted by Oldghm:
MTM's post is not showing up here, did it slip away with the elusive bottom end I'm looking for? Smile
Oldghm


I'm back on page one.

Now, about this bottom end reference. I'm not sure exactly how to take that.... Smile

Mike
quote:
Originally posted by MTM:

We're losing on the distance thing, and we're losing on the equal loudness curve thing as we move further and further into the audience.

Could you pass the Aspirin, please?

Smile


Ok Mike, it finally showed up, thanks for responding, I'm sure I am not the only one to benefit from your knowledge.

So maybe what I need, is a couple more B1's halfway back in the room on a time delay. In reality probably not worth the effort unless the room was greater than 2500 sq feet.

I wonder if the Bose guys have tried that?

I am beginning to understand some things that didn't make sense when I was experimenting with different ways to use the MB4's with the PAS. Utilizing the line out on the PS1 input channels 1 and 2 / mixer / panaray controller / amp / MB4, was an addition of bass response in a way that using the Bass Line Out is not.

Your "phon" explanation helped me to understand some things I noticed while fooling with the RTA the other day. The equipment telling me two very different tones percieved to be very different volumes were registering nearly the same level. It was beyond what I was trying to determine at the time so I never thought too much about it, though it cast a doubt in my mind about the calibration of the unit, that was rebuilt and calibrated about 2 1/2 years ago.

You must be editing, I went back to reference your post and it's missing again.

I think bose has done a great job of designing a product that eliminates many many problems, but the difference in rate of dropoff between the L1 and the B1 may always make it difficult to give the back of a large room the same feel as the front.

Let me get the cotton out of this bottle, ahhh there we go, you want water to wash those down?

Oldghm
quote:
but what if I want each of 4 corners to get the one pint?


Great question ... it's really a tough thing to do with any system. In the example you gave I'm certain that if the folks out back were getting their full pint, then the front is getting a lot more than a pint. Know what I mean? There's no magic here, it's physics that we're up against.

Maybe the time delay thing would work. I'll have to defer to Hilmar on how to do it best. I know that bass is really where the money is. It costs a lot more to produce bass (bigger amps and more cone area) and then you end up with standing waves that require bass traps.
Crazy, huh?

Steve
quote:
Originally posted by Oldghm:
I think bose has done a great job of designing a product that eliminates many many problems, but the difference in rate of dropoff between the L1 and the B1 may always make it difficult to give the back of a large room the same feel as the front.Oldghm


Yes. I was editing. I forgot a question mark.

We do have one thing working for us. All those sabines... er, I mean audience members tend to soak up high frequencies much better than low frequencies. The lows also reflect off walls etc. better than the highs, so the spectral balance (now, where have I heard that term before?) tends to get restored by these means.

We have a brain that is pretty good at "filling in the blanks", and seems to compensate for many anomalies. All in all, I think the basic PAS philosophy is sound: Set it so it sounds right to you on stage. That's what the audience will hear. ± 10%.

Again, you are right about delayed speaker systems out in the audience. They work like a charm. Unfortunately, set-up time just went from minutes to hours. Bummer.

Maybe we should be considering something other than Aspirin.

Water? What's that?

Mike
Hey Guy’s! I kind a scanned this area “The PackLite™ Extended Bass package” to see if it would answer my question and I didn’t see it, so forgive me if this question has already been answered; but I am considering selling my soul to get two PackLite™ Extended Bass packages so I can go strictly with Bose equipment and dump the rest of my gear. I have a bad back and still wish to sound as good as I can. I do a one man band with an Alesis drum machine and I like serous bass. It helps take the focus off my voice and puts it on their feet, if you know what I mean! My question is! Is there a way to hook up two of theses to the PS1 {and if so, how would you do that} and would it be twice as bass-y or am I just wasting my money? … Thanks … Noel … Confused
Hi Noel,

"My question is! Is there a way to hook up two of theses to the PS1 {and if so, how would you do that} and would it be twice as bass-y or am I just wasting my money?"

You can daisy-chain as many units as you want.

You run the PS1 Bass Line-Out to the first one. Then you there is a line out from that that can go to a second, and you can just keep going from there. There probably is a practical limit, but I'm sure you're good for at least 4-6 additional B1s this way.


As to whether or not you need more than one A1 Extended Bass Package, I think this depends on how large your audiences and venues are as well as the kind of music you are playing.

If you've got the cash, just get two and send one back if you find you don't need both. That's probably the fastest way to really know.

But, you can work the other way. Get one (package), and if it's enough - you're done.
Oh dear, I just stumbled across this thread. We are currently working full throttle to get the A1 on the store shelves and the last few weeks in a product development cycle are always a little hectic.

I’m certainly happy to take on all questions and comments so far, but I may have to do it in multiple installs. Feel free to ping me if I’m slacking off (or if I bore everyone out of their mind).

Let’s start with some technical stuff (philosophy will be in the next installment)

1) Crossover
If there is no B1 and nothing connected to the Bass Line Out. The L1 sees frequencies from 110Hz up. Feeding it anything lower, doesn’t make sense, since it couldn’t produce any acoustic output and if would rip the drivers to shreds.

In any other case the L1 sees signals only from 180Hz up. There is no other variation in frequency or gain for the L1 no matter what else happens

2) Bass Line Out and B1 behavior
This is based on the design goal that “You should always sound the same; no matter how much Bass stuff is attached” I can try to explain my view of why this is a good design goal (of which you may disagree) but let’s look at the actual behavior first.

Without Bass Line out
1xB1: 40Hz-180Hz, B1 specific EQ, some nominal gain that we call 0dB
2xB1: 40Hz-180Hz, B1 specific EQ, -6dB as compared to nominal

With Bass Line Out
0xB1: 40-180 Hz, flat, roughly the same gain as 2 B1
1xB1: 40Hz-180Hz, B1 specific EQ, -6dB as compared to nominal
2xB1: 40Hz-180Hz, B1 specific EQ, -12dB as compared to nominal

What this complex behavior does is the following. No matter if you attach 1, 2, or 4 B1s, you will get pretty much the same balance between all combined B1s and the L1s. It’s a little off for 3, 5, 6, 7 & 8 B1s, but still reasonably close.

3) Frequency content of an acoustic guitar
Oldghm, you did some really interesting experiments there. However, you have to be really careful when using an RTA. You can feed these things a pure sine wave at 80 Hz and by turning it up make the 63 Hz and even the 40Hz LED light up. They will be lower than the 80 Hz LED, but still come on. That does NOT mean, that the sine wave contains any other frequency than 80 Hz (it certainly doesn’t). It only means that the RTA has a pretty limited frequency resolution. The 63 Hz LED will respond best to 63 Hz signal but it’s in no way “blind” to 80 Hz signal.
Thus being said, the actual frequency content is not easy to determine. All sounds that have a pitch are certainly constraint to 80 Hz and up (in standard tuning) and there isn’t actually too much energy at the fundamental. However, the “non-pitched” sounds like a hard string attack or whacking the top with your hand can very well have lower frequencies. Unfortunately, I don’t have any hard data on that, but we will measure that at some point.

4) Equal loudness curves
Here is the bunch
http://hyperphysics.phy-astr.gsu.edu/hbase/sound/eqloud.html
These curves tell us two things:
First, the same physical sound energy produces different perceived loudness depending on frequency. You can turn that around into “The physical sound energy required to produce the same perceived loudness varies with frequency”.
Second, this frequency dependency is a function of overall level.

The first statement is not particularly bothersome. Your auditory system is well calibrated to that. A voice sounds normal because it sounds like what you are used to, not because it has “constant sound energy” or “constant perceived loudness” with frequency.

The second statement is much more trouble. It basically says that if you amplify an acoustic source (even if you do it perfectly), the perceived spectral balance will change. This is a well known effect, and most of our home entertainment systems have actually and “automatic loudness compensation” that changes the system voicing with overall level. We actually contemplated adding this to the Personalized Amplification System™ but after some soul searching we thought it would be too intrusive on the musician.
The main corrections are at very low levels, and in most practical live music settings, the effect is pretty minor.
As a rule-of-thumb guideline, turn the bass up a notch as you turn the volume down.


Comments/suggestion/questions welcome. More to come later.

Hilmar
quote:
Originally posted by ST:
Hi Noel,

"My question is! Is there a way to hook up two of theses to the PS1 {and if so, how would you do that} and would it be twice as bass-y or am I just wasting my money?"

You can daisy-chain as many units as you want.

You run the PS1 Bass Line-Out to the first one. Then you there is a line out from that that can go to a second, and you can just keep going from there. There probably is a practical limit, but I'm sure you're good for at least 4-6 additional B1s this way.


As to whether or not you need more than one A1 Extended Bass Package, I think this depends on how large your audiences and venues are as well as the kind of music you are playing.

If you've got the cash, just get two and send one back if you find you don't need both. That's probably the fastest way to really know.

But, you can work the other way. Get one (package), and if it's enough - you're done.


Hilmar's useless fact of the day.
The INPUT and THRU are actually interchangable. Either one will work as input or thru feed, which is handy if you have to make a connection in a hurry on a dark stage. If it goes in, you are in the right jack Smile
Part 2: More technical stuff:

5) L1 versus B1 fall-off with distance
As many have observed, only the L1 qualifies as a Cylindrical Radiator™ loudspeaker, the B1 certainly doesn’t as it looks a lot more like “cubical” radiator. Only a cylindrical source will display 3 dB per distance-doubling falloff. The B1 is a conventional speaker and falls off with 6 dB per distance-doubling. Does that mean that the spectrum gets unbalanced with distance, i.e. not enough bass as we move away from the source?

Not really, and here is why: The observation of so-and-so dB per distance doubling is only true in “free field”, i.e. in some imaginary space that doesn’t have any reflective surfaces. Such a thing doesn’t exist. Most places where you play generate lots and lots of reflections. At any point in the room, the sound field consists of two components: 1) The sound that comes directly from the source aptly called “direct sound” and 2) all the sound that comes bouncing back from the walls, called “reverberant field”.

The level of the reverberant field tends to be roughly the same everywhere in the room. When you are close to the source, the “direct sound” dominates. As you move away from the source, the direct sound drops in level and at some point called “critical distance” the direct sound has the same level as the reverberant field. From this point on the reverberant field dominates and the sound level remains pretty much constant no matter how much further you move away.

The level of the “reverberant field”, the “critical distance”, and the “reverb time” are all close room acoustical cousins and basically determined by the geometry and amount of absorption of the room. In nearly all rooms, there is more absorption at high frequencies and less absorption at low frequencies. Less absorption makes the reverb time longer, the reverberant field level higher, and the critical distance shorter.

Another factor that influences the critical distance is the directivity of the sound source. Let’s make a thought experiment: Imagine a sound source that radiates “normally” to the front but nothing to the back. The direct sound level doesn’t change, but the reverberant level drops by 3 dB since the total energy radiated into the room has dropped by half. That means the critical distance has increased. Of course, that’s only true if you stand in front of the source. In the rear, there is no direct sound any more and the critical distance has become zero. We see that the directionality of the sound source increases the critical distance within it’s beam, cone, pie slice (or whatever shape it radiates), but decreases the critical distance outside.

Now what has all that to do with our initial L1/B1 problem? As it turns out the L1 has a much higher critical distance than the B1. That has two reasons: First, there is more absorption at higher frequencies. Second, the L1 is highly directional: it doesn’t radiate up or down.

Taking all this together we see roughly the following picture: The L1 has a fairly large critical distance, i.e. it’s mostly direct sound and that falls off with ca. 3 dB per distance doubling. The B1 has a short critical distance (not directional, low room absorption) so the behavior becomes quickly a mix of reverberant field and direct sound which tends to also look fairly similar to a 3 dB per distance-doubling fall-off over a good stretch.

To add insult to injury, this is all grossly simplified. In actual rooms, the reverberant field is never really constant, room modes get in the way, the L1 behaves not quite cylindrical in the lower mids, bass levels increase in the vicinity of wall, etc.

If it’s any consolation, we have actually measured the fall off versus distance for our combined system (L1 & B1) in a couple of different rooms and the 3dB per distance- doubling describes the measured data remarkably well.

If anyone is still awake after this lengthy lecture (apologies), I’ll try to tackle the “philosophical” stuff next.

Hilmar
Even though I do not need more bass, I have given this much thought. From my understanding, the added B1's are not really designed to provide more low end. It's designed to provide more sound. (Please correct me if I am wrong) In the tests I did, (I connected a 8 ohm sub to the back of a B1) I got more boom. I got an undisirable (for me) amount of boom. I also got some strange sounds at certain freqs, but this was with two subs that did not belong together. The B1 cable has the resistor installed to tell the PS1 how many B1's there are. Why not run the second B1 with a normal (non resistored) cable if you want more boom? the same thing could be done with the second B1 attached to an A1?
This is a question really... What would the results be with this setup??
Hi Hilmar,

Lots of food for thought here.

Just wanted to thank you for taking the time to explain these things for us.

I will be adding a new section in the Unofficial Users' Guide for the A1 and these notes will be included.

Thank you!
Hilmar,

Thanks a lot for the insight, you have a way of making things easier to understand for those of us who are not as technically astute as we wished we were.

I will be looking forward to your "philosophical" renderings.

Below is a quote from you, from a while back, if you don't mind would you talk a little about what you meant when you said it?

quote:

"oops I forgot ... Crossover is actually 180hz, but it is an intelligent crossover, i.e. it changes frequency and gain depending on how many B1s are attached."


Thanks,
Oldghm
What I meant by "intelligent" crossover is the following:

A) When there are no bass source attached, lower the crossover and try to get as much bass out of the L1 as is reasonably feasible (110 Hz) in this case

B) If there bass sources bring the crossover up to 180 Hz (where the L1 starts to get really efficient) AND adjust the bass gain so that the overall spectral balance is maintained no matter how many bass sources are attached.

These are two guiding principles and the exact that how it is implement is listed in my first post.

I'm sorry if I gave the impression, that the crossover frequency is varied continously. The lower edge of the L1 is either 110Hz or 180Hz but never anything in between.

I hope that clears things up a little, if not, please let me know.

Hilmar
Hilmar, well done mate. I am hanging in there and understand everything you have explained so far.
I just want to let you know how much of a buzz it is to have you do this, it`s like having a class in audio design. Keep up the great work. Best wishes from New Zealand.
quote:
the L1 behaves not quite cylindrical in the lower mids, bass levels increase in the vicinity of wall, etc.


So does setting up the B1s closer to back & side walls, i.e. a corner, and aiming the subs a bit toward the wall increase the perceived bass?

-the village simpleton
Hey guys … If you can add as my packlites as you would like to your PAS isn’t there a point where the lows would drown out the highs? Unless there is also highs coming through the B1s! and if the PAS senses how many B1s are connected, then what does it do to compensate if it doesn’t lower the volume of the B1s? and if it did this, what would be the point of have more, since it doesn’t make it more bass-y, it just makes it louder? And who’s on second? #%&*!@#+*% Confused Eek Confused Eek Confused Big Grin
I think we should come up with a "Packlite Analogy contest"...hehehehe

I think not everyone can relate to the same analogies given...

So I'll try to come up with one of my own...

For you car enthusiasts out there, you might be familiar with Mercedes Benz's power-on-demand system for their V8 and V12 engines. (I think Cadillac has a similar system) What happens is that, driving normally, with the V12 S600, half the engine shuts down.. effectively giving you the power and fuel consuption of a 3.0L V6... as you floor the gas, more cylinders kick in... until all 12 are up and running.

But this is all transparent to the driver... from a stoplight, accelerating normally...you would have the same power and acceleration as an S300... until a certain point where the 3.0L V6 is maxxed out... then you have more headroom.

This is similar to the B1 solution... although the B1's don't shut down, the volume is distributed among the number of B1s you have connected to the system.

For example... (not accurate, but only done to illustrate the concept) volume is set at 5... bass-heavy music:

1 B1 = volume at each B1 100% (only providing 50% of needed bass)
2 B1 = volume at each B1 100%
4 B1 = volume at each B1 25%

Now crank up to volume 10

1 B1 = volume at each B1 100% (only providing 25% of needed bass)
2 B1 = volume at each B1 100% (only giving 50% of needed bass)
4 B1 = volume at each B1 100%

So essentially, with 8 B1s connected, at low volumes, it should should identical to having just 1 B1... but beyond a certain level, to keep up with the L1, more B1 units will be up to the task.

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