Flat Response

[DDF]

Re: Flat Response

All this posts and in my opinion one very big thing about flat response was missed.

We are all effected by noise induced hearing loss and age induced hearing loss. The problem with either one, they don't reduce our hearing evenly across the full 20-20K bandwidth. As a general rule high's always go first than midrange then lows.

This means that what a speaker sounds like to you in our teens is not the way it will sound to you in your 20's, 30's, 50's or 80's. It's common that hearing loss is not even from left to right ear.

Theoreticlly to build the perfect speaker we would need to take a full hearing loss exam and compensate for noise & age induced losses.

This would definately not lead to a speaker that measured flat, but would sound good to you.

Plus, were are all effected by what we have gotten used to in the past.

This is just a theory of mine. Just another thing to think about.


Ed

I think a central premise of the debate is that we want the reproduction to reflect an accurate reproduction of what we think the live event would sound like. EQing the speaker for hearing loss will make it sound "better" than real to the person with hearing loss, by turning the speaker into a hearing aid.

[DDF]

Re: Flat Response

I've got some designs of mine flat on-axis. I've got some with a 1-2db downward slope. I try to achieve the same sound as I perceive it. Variables such as dome tweeter diameter (my only work so far) seem to be an important factor as well as how much felt I've applied that alters the off-axis. Were I to listen to a system at higher volumes than I do now, I suspect that I'd have to roll off the highs a bit more. As it is, I don't crank it up often, so less rolloff tends to sound better. There's no way around Fletcher-Munson.

Were I to try to make a living rather than produce the "most accurate sound", I know I'd design closer to flat to get the most sales. :( I doubt that I would design for what sounds most accurate to me, I expect that I'd have to go for what sells or fail in the business. That's one reason I'd never consider trying to make a living selling speakers.

dlr

Dave, good points all, thanks for contributing your experiences to the debate. BTW, I think boom and sizzle always sold, it kept JBL home audio in business through the 70s and 80s. I find Paul Barton's voicing very natural and realistic and notice he has a tendency for some top end roll off too. The Paradigms always sold better, and in general they always sounded hotter than PSBs.

I still remember when Energy hit the market in the early 80s. I hated the damn things. They were designed using the NRC's early concepts and I found them brutally hot.

[DDF]

Re: Flat Response

My reply to Dave got me thinking more about the room variable.

We're entering an era where the NRC concepts have become gospel. No doubt they point in the right direction, but I've never seen so much weight being put on one set of data (Tooles 1985 AES papers on Listener Preference) as if it applied in all cases. It would be good to see other studies, using more and varied room acoustics as variables, building on Tooles preference tests.

What room did Toole use in his assessment? The IEC room! I have first hand knowledge with these as I designed, had built and put into service (with wall treatment) an IEC room for Nortel.

Problem #1:
The IEC room decidedly DID NOT in any way sound like my living room. It is also a poor representation for more modern open concept home designs (recall this room was built 30 years ago!)

Problem #2
The IEC room was also carpeted. Hardwood is much more common today than in 1985. Hardwood floor creates a more "lively" room. IME the more lively the room, the more high end reduction you want for accurate sound.

Problem#3
Toole only tested in an IEC room. The test did not factor in room variability and its effect and so their results apply specifically to the IEC average room. The more your room varies from this theoretical average, and the less their results may apply to your room. No one knows "objectively" since it wasn't tested. No where in the study did they address this variable and in fact they were correct and careful to mention that the intent was to NOT study this variable.

So why is it such a leap of faith that different rooms or even speaker set ups within one room affect the sound timbre differently (isn't this bloody obvious?), and that the NRC holy grail is fine tuned for an IEC room? Therefore, the more your room/set up veers from this, the more you need to fine tune in differences.

If the IEC room truly represents an average of living room acoustics, then it would be smart for companies to design to this NRC average, to maximize sales. I think Dave hit the nail on the head.

But guys, here's the crux: we are not selling to the mass market, we are rolling our own! Thats the beauty of this hobby that is being overlooked: we should be designing to optimize the experience in our own domestic setting! Build an IEC speaker if you live in an IEC house.

I'll say it again, I think designing your own speakers blindly for flat is lazy.

[Deward Hastings]

Re: Flat Response

I think a central premise of the debate is that we want the reproduction to reflect an accurate reproduction of what we think the live event would sound like.

Some of us do . . . but apparently not all of us. Which is fine . . . I don't force anyone to listen to Mozart or the blues, live or recorded, and I don't have to listen to whatever comes out of their horns (the neighbor's garage band reggae and their kid's hip-hop is bad enough :( ).

De gustibus non est disputandum . . .

Through all the fun (or not) of this thread one thing has become clear, though . . . while some of us still pursue "High Fidelity music reproduction", some of us do not. It should come as no surprise that such different goals would produce different "home" loudspeakers . . . just as those of us in the "Hi Fi" camp for home reproduction would design and build completely different speakers for backline cabs or PA reinforcement.

Non-participating readers of the thread will note the differences, and make their own choices accordingly . . .

[Guest]

Re: Flat Response

So now that we are clear that the average buyer of a flagship NHT, top of the line Paradigm or Revel, etc, etc. and other worldwide sale designs clearly desire accuracy, i.e., linear, undistorted amplitude response that does not satisfy the fringe, let's take a look at how modern music is produced, using SOTA studio monitoring. Are music producers/studio types as discerning as the avg flagship NHT, top of the line Paradigm or Revel, etc, etc, etc., desiring accurate on axis amplitude response (rather than distorted)???

JBL LSR


GENELEC (8260A)


TANNOY Precision


I guess they like "boom and sizzle" native resolution too

cheers,

AJ

[DDF]

Re: Flat Response

I think the reverberant field just gives the ear another chance to look at the information(I believe Dr. Toole mentions this in ch #9, but I may be crazy) and Dr. Geddes says the ear has an integration time of 10-20ms. More reverb, more looks.
Dan

I think this is true, that the integration time for timbre is pretty short for fusing reflections with the direct sound (Zilch summarized these earlier, and I would add Kates thought it was 5 ms).

One qualifier: integration time of the ear is actually as long as 250ms, to integrate the perceived power.

http://www.google.com/patents/about?id=atgFAAAAEBAJ&dq=6178162

However, reverb itself doesn't universally create more intelligibility or detail retrieval. If its too loud, it lessens it. If too quiet, it doesn't optimize it.

I used to design teleconference rooms and there is a reverberation "sweet spot" for voice intelligibility. The room acoustic behaviour targets had identifiable characteristics for RT60, RT30, vs frequency. So, the frequency variation of teh reverb signature and nature of the decay curve over time all effect intelligibility. It will therefore also effect detail perception.

How the speaker loads the room (ie its dispersion) affects these acoustic characteristics.

I think this concept blends well with my earlier points. Not only should the axial frequency response match the room due to the "power response", but the reverb decay curve vs frequency should attempt to reach a particular target, for optimum detail retrieval. For each different room, the dispersion requirements on the speaker could very well differ slightly!

[Zilch]

Re: Flat Response

We're entering an era where the NRC concepts have become gospel. No doubt they point in the right direction, but I've never seen so much weight being put on one set of data (Tooles 1985 AES papers on Listener Preference) as if it applied in all cases. It would be good to see other studies, using more and varied room acoustics as variables, building on Tooles preference tests.

Toole also studied different rooms, and found that the ranking remained the same; that's in part the basis for the adaption component of this. Harman and others use different rooms, as well.

See section 6, Adaption, here:

http://www.harman.com/EN-US/OurCompany/Technologyleadership/Documents/Scientific%20Publications/13686.pdf

Citation:

S. E. Olive, P. L. Schuck, S. L. Sally, and M. E.
Bonneville, “The Variability of Loudspeaker Sound Quality
among Four Domestic-Sized Rooms,” presented at the
99th Convention of the Audio Engineering Society, J. Audio
Eng. Soc. (Abstracts), vol. 43, pp. 1088, 1089 (1995
Dec.), preprint 4092.

[Deward Hastings]

Re: Flat Response

I guess they like "boom and sizzle" native resolution too

You don't say if you've actually *heard* those speakers (in other than a substantially damped and deadened control room) . . . but it's not pretty. Like the B2030A they're OK in a *dead* room . . . in a more "normal" home environment (and sometimes in the control room) anyone interested in "neutral" would down slope 2-4 dB . . .

[MSaturn]

Re: Flat Response

AJ has been preaching the benefits of EQ this whole time .. as he says, build a linear source and then EQ it for the space.

[DDF]

Re: Flat Response

AJ has been preaching the benefits of EQ this whole time .. as he says, build a linear source and then EQ it for the space.

Well, it was Deward, myself and others preaching EQ the whole time, where needed. The above view came late to the party. The earlier stated position was that the speaker should work in all rooms.

Personally, I prefer to change a few parts in my xover vs adding the expense and additional device in the signal chain (which could detract from the sound quality) but YMMV.

[DDF]

Re: Flat Response

Toole also studied different rooms, and found that the ranking remained the same; that's in part the basis for the adaption component of this. Harman and others use different rooms, as well.

See section 6, Adaption, here:

http://www.harman.com/EN-US/OurCompany/Technologyleadership/Documents/Scientific%20Publications/13686.pdf

Citation:

S. E. Olive, P. L. Schuck, S. L. Sally, and M. E.
Bonneville, “The Variability of Loudspeaker Sound Quality
among Four Domestic-Sized Rooms,” presented at the
99th Convention of the Audio Engineering Society, J. Audio
Eng. Soc. (Abstracts), vol. 43, pp. 1088, 1089 (1995
Dec.), preprint 4092.

Awesome! Thanks, I'll read it this weekend.

[Zilch]

Re: Flat Response

Through all the fun (or not) of this thread one thing has become clear, though . . . while some of us still pursue "High Fidelity music reproduction", some of us do not. It should come as no surprise that such different goals would produce different "home" loudspeakers . . . just as those of us in the "Hi Fi" camp for home reproduction would design and build completely different speakers for backline cabs or PA reinforcement.

By my thesis, elitist euphemism for a listening preference in decline.... ;)

Personally, I prefer to change a few parts in my xover vs adding the expense and additional device in the signal chain (which could detract from the sound quality) but YMMV.

In this instance, it's a mere 28 resistors and 12 caps, apparently.... :rolleyes:

[ligs]

Re: Flat Response

Attached are response curves of two well known speakers. Guess which one sounds shrill and you need to cover the tweeter with tissue paper, which one sounds natural?

[spasticteapot]

Re: Flat Response

I guess they like "boom and sizzle" native resolution too

Most people think that studio monitors sound awful.

I, on the other hand, think they sound fantastic.

On one hand, everyone else thinks that I'm mad. On the other hand, choosing audio equipment based on simple metrics ("Is it flat? Does it distort? What's the dynamic range?") is a whole lot easier.

[DDF]

Re: Flat Response

In this instance, it's a mere 28 resistors and 12 caps, apparently.... :rolleyes:

Lost ya on this one.