[JLM]

alpha 03,

The heavy metal crowd (and such) are typically into high spls, not high fidelity and need only PA speakers with boomy bass to recreate the concert experience.  Some have argued that instaneous peaks can reach 120 dB or more but most agree with 110 dB or less.  120 dB is over 1000 times the energy level needed to cause permanent hearing loss!  You start losing me after your references to 120 dB.

I agree that many speaker designers have certain musical genres in mind, but for his business Frank needs accuracy and a wide frequency range.  And I agree that ideally a good speaker should sound good in most any room.  I agree that all audio products should be designed for the "real world", but what is that?  What is the average room?  IMO the range of "real world" or "average" is so wide as to be meaningless.  

I disagree that larger speakers should be able to sound better than smaller ones.  Yes, they should be able to reproduce more/deeper bass if both are properly designed, but smaller speakers can be superior to larger ones in lots of ways.  Brute force is not always the answer.  

I agree that deep bass if foundational to any audiophile system, but deep bass is what cabinet design is primarily about.  Driver size is certainly a factor, but you only have to look that the SPTech waveguide to find a 1 inch driver rated down to 600 Hz to realize that even that simple of a "cabinet" affects lower frequency response.  

It's also my opinion that most folks spend way too much on equipment considering the lousy, compromised  rooms they have to listen in.

[alpha_03]

Bill, I believe you to be in error with concern to how room size effects a given frequency.

The room will either amplify or mute a given freq., nothing more.  The sonic wave of a 15" sub can be easily felt at 20Hz in any typical listening room. As I previously stated, high spl requires high wpc. So if one is going to purchase a hi power amplifier, why then use small drivers? The answer is simple, SPL. Larger drivers get this same SPL using far less power, given that the drivers are of equal efficientcy, however, larger divers (using the previous premise) can also reproduce lower registers of sonics with much greater ease and finese.

Why incorporate another "box" into the mix (your usage of a "sub"), why not simply incorporate the driver where it belongs- in the Speaker cab along with the mid and hi-freq. drivers. Unless of course you belive that bass is not sterophonic, or that time alignment means nothing- I wonder?

The key to any good speaker IMHO is much the same as your thinking, however, if the speaker is really good- one doesnt need a sub do they?

Unless of course were speaking in terms of electrostatics, and that is a whole new ballgame.

There are many companies that make very good ful range BIG speakers, however, only a few do it correctly. Wilson, Martin Logan, Legacy, older B&W, older JBL, Magnepan, just to name a few.

No offence, but size does matter in this case.

[alpha_03]

JLM,

I used the 120dB as a point of reference. I was refering to the ability of a large woofer's ability to produce high spl levels and remain coherient, if correcly designed, over that of an equally designed small woofer type.

The heavy metal crowd (and such) are typically into high spls, not high fidelity and need only PA speakers with boomy bass to recreate the concert experience. Some have argued that instaneous peaks can reach 120 dB or more but most agree with 110 dB or less. 120 dB is over 1000 times the energy level needed to cause permanent hearing loss! You start losing me after your references to 120 dB.

As for car audio (if that is what the above quote is refering to), I have personally seen SPL levels over 135dB. Granted, no sane person would listen to such "noise" for a sustained period, my point was, and remains, and as you previously pointed out, subsonics are the foundation of music in a good audio system- this requires typically large drivers.

edit: Since you made the point that High SPL is somehow not indicitive of Hi-fidelity. Are you stating that HiFi requires lesser SPL to be such? Also, are you stating that high SPL means the music lacks this same Hi-fidelity when compared to a lesser SPL system?

If so, I would have disagree, High fidelity can have high SPL and remain truthful, that is, if the audio chain is designed correctly.

[avahifi]

Regarding how a speaker should be designed to work well in the user's listening room, my ideas are:

Since the "perfect" room should be dead, stiff, and non reflective, the speaker should be designed for this perfect room.  Then it is simply up to the end user to make his listening room as close to the perfect room as possible.

It is imposible for the speaker manufacturer to design a speaker to work at its best in one of the endless varieties of home listening rooms.  All he can do is design for that perfect room standard and let the user spend his accessory money on really good room sound treatmens instead of on Ming Shue Dots and frozen solid CDs.

By the way, all AVA electonic equipment has been given the frozen solid treatment at no extra charge.  The parts before assembly are stored in an unheated building and the temp often hits twenty below or worse.  So you are getting the beautiful sound of frozen equipment for free right here from Minnesota.  That means of course you should avoid Florida and California builders.  

Merry Christmas

Frank Van Alstine

P.S.  I am listening to a pair of ACI Sapphire speakers right now, and my first impressions are VERY favorable.  They don't have the deep bass reach I need for my reference speakers, but what they do, they do very very well and they are very musical. I will report more on them later.

[avahifi]

By the way, I don't mean that the ACI Sapphire speakers do not have good bass performance, their bass extension is very impressive too, especially for a small speaker.  I could live with them personally with the bass reach they do have, which is very good.

Frank Van Alstine

[alpha_03]

I want loudspeakers with the resolution to allow us to hear even minor changes in the electronic designs. When we come up with sometime that we know is technically an improvement, we want to hear it.
 
Our listening arrangement for new electronic design ideas is as follows. We put the two loudspeaker we are using side by side far away from the walls. We make the electronic changes to one channel only of the device we are testing. We set the preamp to mono. One of us makes the hookup of speakers, amplifier, preamp, and so on, randomly scrambling the cables as he goes, so nobody knows which channel is which when we start the playback. Then we play back the familiar source material in mono, and use the balance control to switch from channel to channel.

Considering the above, I believe a good High quality set of headphones would suite the above purpose far better then a pair of monitor speakers ever could. Never the less, left to right side hearing for most humans is not equal, just as left to right vision is never equal, ect. ect. There is a human conditon at play with such a way of determining any possible "flaw" that may exist. I believe here is where a designers expierence takes over, and Science goes out the window. If I may suggest, follow the same principles that an Auditory test center follows when testing human hearing abilty- head phones!!!! (And for good reason, I might add)

However,

I am curious, if it is the principles of room design, and hence speaker performance derived from such, that speaker designers manufacture from, would not all speakers in effect be the same?

Obviously not.

I feel that personal preference plays the major factor in the choice of a speaker system and it's components.

Might I ask what type of music do you "test" your equipment with?

Would it not be fair to state that certain types of music sound best with a given type of speaker at a given SPL?

I really enjoy elctrostatic types, but they lack the low end I prefer, however, to my ears they image better then any cone driver system I have ever heard.

I guess what I am getting at is I seem to prefer a large sound stage, maybe others do not.

If I may, consider testing a pair of Spendor S5's, the Spendor's image quite well IMHO or Legacy Audio's Classic's, I have had the Classics and they are very good sounding, with good low end responce. While I do not own Thiels my friend Bill has a pair of 3.6's and they are very nice also.

[Bill Baker]

Since the "perfect" room should be dead, stiff, and non reflective, the speaker should be designed for this perfect room. Then it is simply up to the end user to make his listening room as close to the perfect room as possible.

 While I do agree here, I think we will all agree that very few consumers are even close to havng a perfect room. Good for evaluation but at the same time, we must consider consumers' enviroments and how our gear will interact with less than perfectapplications.

By the way, all AVA electonic equipment has been given the frozen solid treatment at no extra charge.

 I know what you mean, I have the same thing here with what I call NY Cryogenics. Just put your part out in the back yard for a spell.

[JLM]

IMO the ideal room would be:

1. Isolated from the outside (power abberations, ventilation noise, R/F interferences, and of course outside sounds).

2. Of the proper proportions (retangular rooms) or otherwise properly shaped to avoid the compounding of standing waves.

3. All surfaces to be inert.

4. Larger the better

5. Nearfield setup (improves imaging and helps to minimize room affects).

6. Treated with absorption/diffusion to taste (RT60 between 0.4 and 0.7 milliseconds).  This is NOT a dead room, I've been in anechoic chambers and they are far from ideal listening environments.


Alpha 03, I do not believe that high spl and high fideliy to be mutually exclusive, but simply that 120 dB is a needlessly high standard.

[Watson]

I used the 120dB as a point of reference. I was refering to the ability of a large woofer's ability to produce high spl levels and remain coherient, if correcly designed, over that of an equally designed small woofer type.

As for car audio (if that is what the above quote is refering to), I have personally seen SPL levels over 135dB.

120dB is largely fantasy or marketing.  That's the equivalent of three 15 inch Adire Tempests run to full excursion (sealed).  Not practical for most homes.  Not to mention, it also happens to be the noise level of a jet engine idling on the tarmac.

[avahifi]

I really wonder what a speaker builder can do effectively to design in non-linearities into his speaker system to compensate for room non-linearities?

It sounds like a really impossible premise to me.

"Buy my speaker because the built in 5000 Hz resonant peak will make up for your room's dip in the region"  sure, maybe, duhhh, not a chance.

By the way, some of you are just not reading my original statement.  Pray tell how I am supposed to evaluate power amplifiers on headphones?

For your info, I recent was able to evalute the highly regarded B&W 800D speakers on my electronics.  Great sound stage, rock solid image, great transparency and detail, no rough edges, great balance, but deep bass did not have the reach and power and linearity of my 20 year old B&W 801s which have a bigger woofer and a bigger woofer cabinet very well tuned (and a crossover I redesigned and damped midrange and tweeter mechanical structures).

The B&W 800D made the cover of The Absolute Sound with an excellent review.  In my book they are a "tilt - reject" because for $20,000 a pair they should have a much better bottom end.  A $20,000 a pair loudspeaker system should do everything near perfectly, not just part of the range.  They would not meet my needs at all.

Keep your observations coming, but keep them polite and kind please.

Further listening to the ACI Sappire speakers -- they are a pleasure to listen to, maybe with an overall very slightly warm cast, but certainly very nice to hear all day long.  They come with port plugs that I have not tried yet, not have I downloaded and read the owners manual from the web site, so the jury is still deliberating.  I like them and wish ACI made that big floor standing speaker I am searching for.

Frank Van Alstine

[zybar]

Frank,

Why not contact Jim Salk and see if you can hear his HT3's?

They will meet your full range requirements while being very revealing and musically enjoyable.

George

[zybar]

I really wonder what a speaker builder can do effectively to design in non-linearities into his speaker system to compensate for room non-linearities?

It sounds like a really impossible premise to me.

"Buy my speaker because the built in 5000 Hz resonant peak will make up for your room's dip in the region"  sure, maybe, duhhh, not a chance.

By the way, some of you are just not reading my original statement.  Pray tell how I am supposed to evaluate power amplifiers on headphones?

For your info, I ...

The way to handle in room issues is to employ a device such as the TacT 2.2x.

George

[avahifi]

What is a Tact TAC2?  Can you provide me with a web link?

Thanks

Frank

[avahifi]

TACT 2.2X I mean.

[zybar]

What is a Tact TAC2?  Can you provide me with a web link?

Thanks

Frank

Here are the appropriate links:

TacT:

http://www.tactlabs.com/Products/RCS22X/index.html

Salk Sound:

http://www.salksound.com/ht3.html

Enjoy.

George

[avahifi]

Oh goody!!  Tact 2.2!!!  Pay $4000 extra to get some wonderful digital processors and amplifiers in you system.

Duhhh, how about spending that money on some Sonex. acoustic wallpaper, and heavy carpeting instead?  No way that Tact machine is going to get rid of high and mid range nasty reflections and echos from your room.  What a waste.

I have contacted Mr Salk and a set of his demos are promised to me eventually.  Looking forward to that.

Frank Van Alstine

[zybar]

Oh goody!!  Tact 2.2!!!  Pay $4000 extra to get some wonderful digital processors and amplifiers in you system.

Duhhh, how about spending that money on some Sonex. acoustic wallpaper, and heavy carpeting instead?  No way that Tact machine is going to get rid of high and mid range nasty reflections and echos from your room.  What a waste.

I have contacted Mr Salk and a set of his demos are promised to me eventually.  Looking forward to that.

Frank Van Alstine

Frank,

I was hoping you wouldn't have such a closed mind, but to each their own.

My room IS treated and the TacT does the things you think can't be done and more.  It certainly isn't a waste and it certainly isn't magic or vodoo.

Hope you find your speakers.

George

[ctviggen]

The TACT 2.2x is more expensive than that.  I think that digital room correction (DRC) is not a cure-all (it will not correct modal ringing, for instance, though it could reduce the effects of such), but can be beneficial.  If you have the time, here's a free version:

http://drc-fir.sourceforge.net/

You just have to supply the time.  This is what I'm doing this year -- I've already ordered Linux and will use the above-referenced program to see what digital room correction is about.  The nice thing is you can operate on a single CD and just test the "before DRC" and "after DRC".  If I like the effects of DRC, I'm going to set up a Linux-based, fanless PC to do the correction real-time (i.e., instead of correcting my entire library).

[Bill Baker]

I think Frank is in a touch situation here. We all know there is no such thing as the perfect loudspeaker and even if there was, the perfect loudspeaker would only meet it's potential in the perfect room which also does not exist.

 Today I had a recording engineer (and studio designer) in my showroom auditioning every speaker I had available. All his comments were very open minded as he kept in mind the room itself. He was able to realize what issues were a result of the speaker being in a room not best suited to optimize thier performance. He was also able to give me a lot of good pointers on configuring my room for a better showroom enviroment. Now that I am starting to get more audition appointments, I think the time has come.

 All my designs and modifications are based on the fact that [most] consumers will be placing a given product in a real world enviroment. This could be a living room, dining room, etc. As we all know, niether myself or any other dealer/manufacturer can predict how any given product, especially speakers, will integrate into ones personal enviroment.

 I think Frank's best bet is to see what manufacturers are willing send him a pair of thier speakers to evaluate in HIS enviroment. We can only suggest options to consider which in the end, will only make things even more difficult for frank to make a decission.

[Brian Cheney]

What can a speaker designer do to compensate for nonlinearities of the listening environment?

It's up to the audiophile to make his room a good listening environment.  I have some advice on my website to that effect, in the Designer's Corner under How To Tips.  Damp surfaces behind, beside and above the speakers as best you can.  Add bass traps in corners.  Find an optimum speaker position in the room which least excites room modes.  Same for the listening position.

What did I do to address the matter of the listening environment?  
1. I make the speaker as linear as possible on axis.
2. I optimize listening quality on axis with first-order filters adjusted to fine tolerances (around 1/100% of one percent) plus extensive driver matching.
3. I make or modify all my own drivers so I have control over their design parameters and don't have to pay high prices for European off-the-shelf stuff which does not perform as well as I can make it.
4. I include level controls which will tame a bright room or deemphasize a forward midrange due to same.
5. I permit user adjustable system Q to compensate for placement and series R of the speaker wire and source impedance of the power amp.
6. I add a Constant Directivity Wave Guide over the speaker so that on-axis and off-axis horizontal dispersion is the same 20Hz-20kHz over a 180 degree angle.  This compensates for the poor off-axis response typical of first order networks due to lobing/wave interference.

There are other ways to accomplish the above, all of which are very important to sound quality. I am satisfied that my methods work, however.