How much power PAS has ?

What problem are you trying to solve? I can tell you that the system has a total of 750W but that won't mean much if you understand how this speaker is very different from a conventional speaker.

Please keep in mind that Watts are a measure of electrical power, "How many Watts is that light bulb?" for example, so keep in mind, not all sound reproduction Watts are the same -- "How loud is that lightbulb in the kitchen?" sounds silly doesn't it?

Can I try to help with a problem you're trying to solve?

Steve
Hi , I'm not trying to solve any problem other then I asked. Thank you - you just answered my question :-) I'm a small town entertainer - I've got Roland E-70 and Yamaha PSR 2100. Maybe in the future I would go for something like this... At this moment conventional sound system makes me looking better because I am on the stage just by my self :-) And I already have it.... What would I do with a system that I paid once ( about 10 years ago ) close to $ 2000 . PAS is way to expensive!!! The other think I wonder how does it sound combined with vocal, as you may know playing PSR 2100 vocal goes right trough keyboard.
It sounds like your set up is not the typical "pro" rig (if such a thing exists). I believe you are using an auto-arranging keyboard and using its processing for vocals.

I can tell you that the PAS does a great job of handling keyboards and vocals... if you like transparent sound. What comes out is pretty much what you put in. I've been amazed at the amount of sound that the unit can generate and the flexibility that it has given its intended purpose: "personal amplification system".

It is expensive, but it sounds better than my Mackie 808S and JBL 3-way system. There is more low end, more volume and much less harshness. The cost, by the way, was about the same as my L1/2B1 system.

So I guess, if you want to step up in performance, it costs about $2,000. Only you can decide if the investment is worth it for what you are doing. However, it is unfair to criticize the system based on cost. For the gigs I play, your system wouldn't work for a monitor for me. It's all relative.

Good luck and keep your mind and ears open.
Matt
ziggy,
As a keyboard player myself, I could not imagine not using this product. Period.

Keyboards are very unique instruments. They have the capability of covering the entire audible spectrum. Most keyboard players spend all of their hard-earned money purchasing a good keyboard rig and then are left wondering how to get all of those great sounds out on stage and into the audience. Sound familiar?

Ever listen to your keyboard over headphones and wonder why you couldn't get that sort of fidelity on stage? It's my experience with this new product, the Personalized Amplification System, that you can. I saw that you mention in your post that this product is too expensive for you. I really think that after you try it, you'll probably wonder why you waited so long to improve your sound to the degree that I and so many other owners have come to experience. I just had to add my opinion here since I think that this product is a HUGE sigh of relief for keyboard owners out there who have never been satisfied with getting their sound out of their keyboard and into the air.

To dig further into your original question, I'd like to do a comparison for you. There are many reasons why we don't casually publish specifications on our products. This is a great example of why.

You asked about power. Steve did a great job relaying the discontinuity between electrical power and sound pressure level.

The real "magic" in the Personalized Amplification System is the L1 Cylindrical Radiator loudspeaker. The L1 projects sound much differently than conventional loudspeakers. The L1 radiates a cylindrical wave front. Check out the image below.


It projects sound out over the stage and into the audience in a wedge-shape pattern with little sound being radiated above or below the L1 loudspeaker. This means that all of the acoustic power is for the most part restricted into this two-dimensional area. It happens to be that this SAME area is where you the musician is and also where your audience is.

Let’s look at the wave front of a conventional loudspeaker.

Spherical in shape and three-dimensional, a conventional loudspeaker is very wasteful in projecting energy into a listening space. It sends sound out in a shape that projects the sound energy to the ceiling, floor, and upper walls where there are no listeners. Because of the shape of this wave front, it’s characteristically very, very loud and harsh directly in front of it and, with distance, dramatically drops in volume and tone. In other words, as you move away the sound changes quickly.

Let’s do a general comparison of sound levels with the L1 verses a conventional loudspeaker (please stick with me, I’m getting to your question). I’m going to start with the assumption that both loudspeakers are powered from a 500W power amplifier and are set so at 5 feet in front of each of them, the sound you hear is 100dB SPL.

Keep in mind that a change of about 3dB is when most human ears hear a slightest change in sound level. Try this sometime: While listening to your home stereo or car radio, slowly turn down the stereo enough so you just hear that the volume has been reduced. This is around a 3dB change. Also, human perception of half the loudness intensity is around 10dB. So, with those being said, check out this comparison:



So, at 80 feet it looks like a conventional loudspeaker will be 12dB softer than the Cylindrical Radiator loudspeaker!

The answer to your question of power in electrical watts is not that easy. Wherein the past with a conventional system you were somewhat used to a 500 Watt amplifier providing a familiar sound level. All is changed now. It is not a direct comparison. See?

The short to your answer is that the PS1 power stand has 3 250W True RMS amplifiers. The real question here is: WHAT SIZE AMPLIFIER is required to drive the conventional loudspeaker to match the sound level of L1 Cylindrical Radiator at 80 feet (using the above example)? Want to take a guess?

The answer will surprise you.

edit-repaired image links
Okay Steve,
(all quotes are from Kyle's posting)
If the original question was...
quote:
The short to your answer is that the PS1 power stand has 3 250W True RMS amplifiers. The real question here is: WHAT SIZE AMPLIFER is required to drive the conventional loudspeaker to match the sound level of L1 Cylindrical Radiator at 80 feet (using the above example)? Want to take a guess?


and the
conventional system is delivering 76 db vs the
L1 delivering 88

and if
quote:
human perception of half the loudness intensity is around 10dB.


and
quote:
Keep in mind that a change of about 3dB is when most human ears hear a slightest change in sound level.


then at 80 feet the L1 "sounds" about twice as loud (plus nearly a little bit that would be barely perceptible). (88 = 76 + a-teeny-weeny-bit)

Sometime - a long time ago someone told me that to achieve double the perceived volume, (assuming all other factors are equal), requires an order of magnitude (ten times as much) more input power.

Wild Screamin' Guess

Are we talking 500 x 10 = 5000 watts to get to a 88 db level at 80 feet?

And while we are considering this, would we achieve the same result with 10 conventional 500 watt amps & speakers?
For Steve-at-Bose

quote:
The real question here is: WHAT SIZE AMPLIFER is required to drive the conventional loudspeaker to match the sound level of L1 Cylindrical Radiator at 80 feet (using the above example)? Want to take a guess?



You sound too despondent. My guess is 8000 watts. Start with 500 watts and double the power for each 3db, right?

Thanks from Ivan
Okay were just gussing, no penalty for wrong answers I'll say 5500 watts. But what I really want to know is what is the db of that conventional system at 5 feet when you have achieved 88db at 80 feet? My ears hurt thinking about it. Probably not a good time to have front row seats.

Oldghm
BINGO

Ivan's got it right. You need 12 dB more at 80 feet. 12 dB corresponds to 16 times the power and if we assume 500 Watt for the L1 you would need 16*500 Watt = 8000 Watt for a conventional speaker.

To answer Oldghm's questions: That system would produce 112 dB at 5 feet.

I'd like to inject a little caution here: Our Cylindrical Radiator(tm) loudspeaker is a very good approximation to a theoretically perfect line source but it is just an approximation (since the real thing is physically not feasible). Above a certain distance it will actually behave like a conventional speaker and at 80 feet it is certainly not fully cylindrical anymore. The exact behavior is very complicated and depends on the frequency and the environment. We typically found that when you adjust to equal levels on stage, you easily get about 10 dB or more volume from the Cylindrical Radiator(tm) loudspeaker in most audience locations.

It's at least equally important to consider what's going on on the stage, i.e. very close up to the speaker. Say you adjust the level at 12 feet (where your band mates are) to 95 db. At 2 feet (where you are) the level of the Cylindrical Radiator(tm) loudspeaker will be a comfortable 102 dB. A conventional system would produce more then a 110 dB at 2 feet.

Hilmar

[changed "real" to "theoretically perfect"
Congrats Ivan,

Corollary (theoretical) Question:
Is 2 (sound sources) x 250 watts going to produce the same sound pressure level as 1 (sound source) x 500 watts ?

or

Is 16 (sound sources) x 500 watts going to produce the same sound pressure level as 1 (sound source) x 8,000 watts ?
ST
Unfortunately that's close to impossible to answer because that is a really complex phenomenon. If you have two sound source that are
a) relatively small
b) not driven very hard
c) you look only at relatively low frequencies
then you get 6dB more sound pressure level (SPL) from 2 as compared to one.
Our B1 is a good example for that: 2 B1s give 6 dB more than one. You gain 3 dB by simple doubling the electrical power (250 Watt for two, 125 Watt for one). The other 3 dB are gained by doubling of acoustic volume, cone area and close coupling between the speakers.
To get the same SPL (as 2 B1s) from a single B1 you would actually have to hit it with four times the power (500 Watt).
Other cases get really complicated and depend heavily on the specifics and physical arrangement of the speakers in question. Consider the L1: using more sources actually reduces the SPL dramatically at some locations (above and below) and increases it at others (at some distance from the L1 but inside the wedge).

Hope that helps

Hilmar
quote:
Originally posted by Hilmar-at-Bose:
ST
Unfortunately that's close to impossible to answer because that is a really complex phenomenon. 8< --- snip --- >8

Hope that helps

Hilmar


Thanks Hilmar. I was afraid it was one of those ... the answer depends on a myriad of inter-related and seemingly unrelated factors ... types of things.

I think my ears understand all of this better than my head does.
Oldghm
quote:
So if we have 5 bandmates on stage with PASs (5 X 750 = 3750 watts) each at 95db at 12 ft. What happens to the db spl of the group as a whole?



at a spot where you 12 feet away from all 5 players and they are all playing different things you would get about 102 dB.
The rule-of-thumb here is that you get 3 dB for every doubling, i.e. 3 dB for 2 players, 6 dB for four players and about 7 dB for 5 players.
Please note, that in a typical band setting the players rarely play at the same level at any one point in time and that usually the overall level is determined by the loudest player (singer or soloist).

ST
quote:
Thanks Hilmar. I was afraid it was one of those ... the answer depends on a myriad of inter-related and seemingly unrelated factors ... types of things.

I think my ears understand all of this better than my head does.

You're not alone. I have a Ph. D. in acoustics and EE, tought at college, worked in commercial and academic research for 15+ years and it sometimes still confuses the heck out of me. It's a good thing we have those ears Big Grin

Hilmar
[QUOTE]Originally posted by Steve-at-Bose:
What problem are you trying to solve? I can tell you that the system has a total of 750W but that won't mean much if you understand how this speaker is very different from a conventional speaker. /QUOTE]

Hello,

finally registered to the forum after a long time of just reading. What is said here, is also said in the FAQ, but one thing is still a bit unclear to me..

"Each of the two sections of the Cylindrical Radiator™ loudspeaker handle 250 Watts and another 250 Watts are delivered into up to two B1 bass modules."

I am assuming that this means channel 1 and 2 gets 250 watts from one poweramp, and channel 3 and 4 getts 250W from another poweramp. Is this correct, or is it really (this would be ideal) that channel 1 and 3 share an amp, and channel 2 and 4 share an amp? I'm sure this is not the case, but I have to ask anyways, since I most probably would never use channel 3 and 4.

Btw, I know that watts is not a way to measure sound pressure, which I truly experienced with my 6 watt Cornford Harlequin (which I am thinking of replacing with a PAS. Maybe?)
quote:
Originally posted by Flaat:
...I am assuming that this means channel 1 and 2 gets 250 watts from one poweramp, and channel 3 and 4 getts 250W from another poweramp. Is this correct, or is it really (this would be ideal) that channel 1 and 3 share an amp, and channel 2 and 4 share an amp? I'm sure this is not the case, but I have to ask anyways, since I most probably would never use channel 3 and 4...


Hey Flaat -

Actually the four input channels are like a mini-mixer, with the output of the 4-channel input stage feeding all three power amps. The cross-over section will split the high frequencies to feed the L1 sections, with 1-250W amp per section, and the lows go to the B1 amp, with output of 125W with 1-B1 connected, and 250W with two B1s connected. Hope that helps!
Hi there,
wonderful reading in this thread.
Just wondering, the figures given for the PAS, is that without any gear or musicians in front of it?
With a conventional PA, the speakers are out front with no physical obsticles that a PAS system might have in front of it, like a band member or drumkit.
Tom
Hi Tom,

Great question. Here is something from the Bose L1® Frequently Asked Questions.

quote:

What happens if a musician is blocking the view of an L1® system? Doesn't that block the sound?

Sound can diffract (bend) around objects. As long as a musician isn't standing directly against the L1® loudspeaker, the sound diffracts around the musician and other objects like a keyboard or instrument.




I understand that this is not an answer to your specific question but it does explain what I hear when I use the L1®. That is: musicians and gear have little or no noticeable impact on the sound of the L1® in normal stage situations where the L1®s are behind the performers.

Does that help?

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