Author Topic: Anyone use Bose Acoustimass speakers? (Read 1206 times)

MrRiplEy[H] · « **Reply #30 on:** March 21, 2006, 01:03:59 PM »

Yes seraphim, as I said Bose design ideology is aimed towards producing pleasant background music for a large area instead of producing the highest fidelity possible.

Suitable applications would be home theaters for more than 2-3 persons and public address systems (concerts etc).

Skuzzy:

The low frequency behaviour of a room is dictated by the physical size and most importantly building materials. Wooden structures are especially good for bass reproduction as they absorb and pass the sound. Brick or cement walls then again create a very high field of low frequency reflections and phase cancellation.

Typically the cancellation time of sound increases directly with lowering of the frequency (high frequencies are easily absorbed by soft materials where low frequencies are not) the absorption is again tied directly to the wavelenght of the sound. The higher the wavelenght (lower frequency) the larger mass is needed to absorb the sound.

Skuzzy · « **Reply #31 on:** March 21, 2006, 01:06:52 PM »

Speakers aside, if you are on a budget. Spend more on the amplifier/receiver than the speakers. A good amp can make poor speakers sound ok, but no matter how good the speakers are, a bad amp will make them sound bad.

Also, try to match the wattage/output of the amp to the room you will be placing it. An under-powered amp for a room will sound terrible. Better to have a bit too much, than too little. I typically use the following equation.

square feet * 30W = total wattage

Seraphim · « **Reply #32 on:** March 21, 2006, 01:08:37 PM »

In any case, all the theory & money in the world goes out the window, because I use my ears to make my purchase decisions for speakers. In this case, to me, Bose sounded better than all the other speakers I tested. I guess a natural sound to me is different from what a speaker guru considers natural.

MrRiplEy[H] · « **Reply #33 on:** March 21, 2006, 01:21:55 PM »

Quote

Speakers aside, if you are on a budget. Spend more on the amplifier/receiver than the speakers. A good amp can make poor speakers sound ok, but no matter how good the speakers are, a bad amp will make them sound bad.

Rofl here I again disagree with you. The speaker is the most important link in the sound reproduction chain.

Given that the amplifier is suitable for its task (it has enough power to match the sensitivity of the speaker, flat frequency range and can handle impedance changes) the quality of the amplifier is the least dominating factor in the sound.

Only if the amp is broken or underpowered it becomes a real problem. Most modern amps have a perfectly flat frequency response with distortion levels under 1%. Speakers then again have gigantic differences in both linearity and distortion levels. On bass frequencies it's common to see 10+% harmonic distortion.

Remember that a speaker with a sensitivity of 87db / 2.83V @ 8ohms (1 watt) will need ten times the wattage to play at 90db (double amount of sound). The grid is logarythmic, for each doubling of the sound you need ten times higher amp power. So overall wattage required is tied to the sensitivity of the speaker and naturally the maximum sound pressure wanted.

A typical hi-fi listener listening to a typical hi-fi loudspeaker will consume an average of 15 watts of amplifier power.

Skuzzy · « **Reply #34 on:** March 21, 2006, 01:22:16 PM »

Quote

Originally posted by MrRiplEy[H]
The low frequency behaviour of a room is dictated by the physical size and most importantly building materials. Wooden structures are especially good for bass reproduction as they absorb and pass the sound. Brick or cement walls then again create a very high field of low frequency reflections and phase cancellation.

That is true, to a degee. You and I realize there are many factors involved here and I will assume you are skimming a bit. The base of the sub-woofer should not sit on a wooden floor, which is not isolated from the rest of the room, for example.

Quote

Typically the cancellation time of sound increases directly with lowering of the frequency (high frequencies are easily absorbed by soft materials where low frequencies are not) the absorption is again tied directly to the wavelenght of the sound. The higher the wavelenght (lower frequency) the larger mass is needed to absorb the sound.

Depends on the amplitude of the frequency.

As far as room materials go. Most rooms are a grab bag of surface and hardness materials. And because of that, every room has to be tuned differently.

Skuzzy · « **Reply #35 on:** March 21, 2006, 01:28:28 PM »

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Originally posted by MrRiplEy[H]
Rofl here I again disagree with you. The speaker is the most important link in the sound reproduction chain.
Remember that a speaker with a

So you think spending $20,000 on a set of B&W speakers and hooking them to a $100 receiver is better?

You make asumptions here. Let's quantify something here. There are about 10 amplifiers in the world I call really good *home* amplifiers. Sound reproduction is absolutely accurate. When I say *cheap* speakers, I am thinking of those who costs less than $800 each (U.S.).

Specs mean diddly if the acoustic reproduction is not accurate. It is too easy to fudge frequency response and noise levels.

You can laugh all you like. I have heard the results of people buying high end speakers and hooking them to an Onkyo amp. It sounds bad. Yes, hooking up cheap speakers to a good ampis also bad. But not as bad as a bad amp makes any speaker sound.

MrRiplEy[H] · « **Reply #36 on:** March 21, 2006, 01:33:30 PM »

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So you think spending $20,000 on a set of B&W speakers and hooking them to a $100 receiver is better?

A $100 amplifier will not be up to the task of playing $20k speakers obviously. But having a second hand Mark Levinson @ $2.5k driving those $20k speakers is the ratio I'd like to see in my own set.

Given that the amplifier is one of hi-fi quality to start with, it's suitable for speakers up to 5-10x the price range usually. If you put equal amount of money to both speakers and amp and invest tenfold amount of money to replace the amp, you will get _less_ improvement to overall sound than only doubling your speaker price.

And this I can vouch on my grave.

On home theater amps the situation is even worse because compared to a normal stereo amp they contain 5-8 power amps for the same price. So in order to get the same level of sound from a home theater amp you need to invest 5-8 times the money than you would compared to a stereo set. You won't get really hi-fi for $1000 on multichannel where that money will buy you a quality stereo amp.

Skuzzy · « **Reply #37 on:** March 21, 2006, 01:42:37 PM »

True if you start with a Mark Levison amp. But if you start with an Onkyo, or some other low end amp, it may not be true.

Certainly there is a breaking point in where the money should be spent. But, when talking low end systems (Acoustimass is low end) then the speakers are all pretty much the same.

For the most part, if you only have $500 to spend, then spending $300 on the amp and $200 os speakers will yeild a better combination than vice-versa. I work from the premise of, low-end speakers are not nearly as bad as low-end amps.

And because the home theater amp has to drive 5 or 6 speakers, it is even more important to get a decent amp.

MrRiplEy[H] · « **Reply #38 on:** March 21, 2006, 01:45:58 PM »

Quote

Originally posted by Skuzzy
True if you start with a Mark Levison amp. But if you start with an Onkyo, or some other low end amp, it may not be true.

Certainly there is a breaking point in where the money should be spent. But, when talking low end systems (Acoustimass is low end) then the speakers are all pretty much the same.

For the most part, if you only have $500 to spend, then spending $300 on the amp and $200 os speakers will yeild a better combination than vice-versa. I work from the premise of, low-end speakers are not nearly as bad as low-end amps.

On that I agree, a budget of $500 is not enough to begin with as it won't even buy you a decent multichannel amp. But when the price range goes to $1k+ (per item) it's advisable to invest more money to the speakers instead of the amp. IMO anyway.

Skuzzy · « **Reply #39 on:** March 21, 2006, 01:51:43 PM »

Like I said, there is a breaking or break over point. I agree once you have a good budget, you should spend more equally, and as the budget increases, more should be spent on speakers.

By the way, my home setup is comprised of B&W speakers (the THX-8 system; 4 surrounds, 3 mains, 2 subs) driven by a Yamaha DSP-A1, and two MacIntosh amps (7502 drives the subs, 7503 drives the mains, and the surrounds driven by the Yamaha).
To me, it represents a decent home theatre configuration.

MrRiplEy[H] · « **Reply #40 on:** March 21, 2006, 01:59:14 PM »

Your system sounds very nice Skuzzy even though the A-1 starts to age a bit already. I believe it only has support for 5.1 DD?

I have the AX-2 myself. Then again, I don't feel the slightest need for 7.1 audio.

I'm a DIY electrostatic speaker builder btw.

Skuzzy · « **Reply #41 on:** March 21, 2006, 02:08:11 PM »

Yeah, the A1 only has support for 5.1 (7.1 using the Yamaha proprietary DSP feature which is not Dolby). The speakers are getting old as well. I have not decided about them yet. I may order some replacement drivers from B&W.

I am looking for a new amp for Christmas. I may go all separates on this next go-around (decoder, amps..). I really love the sound of the A1 though.

I build speakers as well. Not electrostatics though.

phookat · « **Reply #42 on:** March 21, 2006, 03:21:46 PM »

Curval-- Horns are the plastic things sometimes on speakers that look like air intakes. Ports also can look like this, but horns are often at the top of speakers and centered. Anyway, I think they sound bad.

MrRipley-- I know you can only change direct radiation with an EQ, but I maintain that changing the direct radiation has an impact on overall sound. Using a parametric EQ it is definitely possible to eliminate painful resonances and solve other similar problems caused by room structure or speaker non-flatness. Again it is not the perfect solution...but in a HT environment where you *cannot* rely on direct sound only, this is a better solution than electrostats. You've heard stats off-axis, and I'm sure you'll agree they sound pretty muffled.

Skuzzy-- Below clipping and operating within their design parameters, all amps are gonna sound about the same. I'll have to agree with MrRipley on this one. If you can actually hear amp differences under those conditions, there's a guy in North Carolina that will give you $10,000 to prove it in a double-blind level-matched test. No kidding. Now, of course, some amps are more powerful than others and they'll get louder, and that part is important. But other than that, speakers are electromechanical, and they are going to have a bigger effect. The room may have an even bigger effect than the speakers.

Skuzzy · « **Reply #43 on:** March 21, 2006, 03:31:36 PM »

phookat, I would take him up on that one. If you ever get to this area, allow me to take you to my "toy" shop and let you listen to some amps. I have sold a fair number of high end amps and speakers due to the fact that people can hear the difference, quite easily. It can be very apparent.

Now, with that said, I will agree you would be hard pressed to hear the difference between a $2,000 amp and a $10,000 amp. Once you get to a certain level the differences become quite small. Same goes for speakers. The difference between a $10,000 speaker and a $2,000 speaker can be quite small.

But, it is quite easy to hear the differnce between an $1,000 amp and a $2,000 amp. And it is quite easy to hear the difference between a $1,000 speaker and a $10,000 speaker. The differences will depend on the material played through them, and the room acoustics. Some material just sucks no matter what. Some doesn't.

phookat · « **Reply #44 on:** March 21, 2006, 03:49:28 PM »

Seriously, Skuzzy, you can set up an appointment with this guy. His name is Richard Clark, and he is associated with Carsound magazine (as well as owning an audio engineering company of his own). If you go to the carsound.com forums, he has a forum there in which he posts...and you can contact him there and set it up. I should warn you though...he has had this challenge on for about 30 years or so, and he's been to audiophile conventions with his double-blind test rig. Literally thousands of audiophiles have tried, with all sorts of amps, and failed.

I do agree that speaker differences become marginal as you go up. There's a limit to how flat it can be, and if you are already +-2db 20-20K, then there's not really much room for improvement no matter how perfect the alternative.

Incidentally...if you are planning on building speakers soon, you should check out some of the stuff available in the car audio DIY market. Some of it is really very good, and relatively inexpensive. The Koda 6 driver from adireaudio.com is extremely smooth, and the 9kv2 from edesignaudio.com is an excellent 8" driver with a ton of xmax for an 8. For tweeters...I love my Raven ribbons.

Seraphim-- again, a speaker with an uneven FR will sound good with some things, and poor with others. This is the disadvantage of using only your ears and ignoring the graphs. Both ears and graphs should be used in selecting speakers.