THE IMPORTANCE OF TIME DOMAIN RESPONSE MUST READ


Speaker designers ignore or downplay the importance of TIME. Why?

A high end speaker should be as accurate as possible and that means it should not only be optimized with regard to frequency response but time response.

Back in the 70’s and around that time, speaker engineers thought that a perfect speaker would be one that had a flat response. This idea has waxed and waned in popularity over the years and even now there is no consensus.

What the speaker engineers forgot to consider is Time response.

The time reponse of a speaker is how fast it starts and stops. A perfect speaker would have a perfect time response of 0. Since this is not possible, we must get as close to it as possible. The problem is speakers engineers have neglected this aspect of the design and so speakers over the last 40 years have not improved in this respect.

Time is such an important aspect of the sound we hear. We not only hear tone but also time. The brain can detect time differences of only a few microseconds. Experiments have shown that the start of each note is what we use to determine what instrument is producing that sound.

We must ensure that our crossovers do not smear the time response because it will be heard by our ears. Time inaccuracy is why high end speakers do not sound like real instruments.

Diffraction from the cabinet can also cause time smear. We need spherical cabinets not square boxes. Tweeters need to be time aligned in order to ensure that when the woofer stops so does the tweeter. When the woofer starts, so must the tweeter. The woofer itself has to have a Qts of ZERO to prevent time smear. Ports must not be used or else you will get ringing.

We need to make it mandatory for speaker companies to publish the time response of all their speakers so that consumers can easily compare and decide exactly what they want. Some may actually prefer a speaker that has a poorer time response and that is fine. The problem is, we cant decide unless we know what we are buying can we?

Unfortunately, 90% of speakers on the market, even high end speakers have ports. And they are also made of cheap wood, even though there must be better materials by now. Some materials ring more than others.

So dont be deceived folks. If you want better speakers, you will probably have to make them yourself because speaker manufacturers dont care about sound quality. They spend millions of dollars on anechoic chambers all so that they can get a flat response but they spend zero effort on better time domain response. We are being duped.

kenjit

@erik_squires 

Kenjit, who has never designed a speaker,

This is also a false accusation. I have designed speakers. But just as all speaker designers will not reveal their secrets, why should I? If you have spent years tuning a speaker why should you give away all your hardwork? Does Fritz tell us the values of the caps he uses in his designs so that others can copy his work? I dont think so. I have worked hard to be a champion and I will not help my competitors gain an advantage and put my status at risk. 

Of course they dont know what they’re doing. A speaker is supposed to reproduce the signal you give it. Yet all high end speakers sound and even measure differently. They can’t all be right can they?

@kenjit How wold you define “right”?
Are there some specific measurements that show when one is more right than another?

 

How wold you define “right”?
Are there some specific measurements that show when one is more right than another?

we need to look at the cumulative spectral decay to ensure that its 0ms at all frequencies from 20hz to 20khz. I've never seen any speaker come close to that. 

so you see @holmz 

the spectral decay ensure its oms at frequencies...... I dealt with this guy for a week everyday,  he did not absorb a thing..... complete aggravation 

Kenji,  you are confusing the X and Y axis with the L & V axis.   

we need to look at the cumulative spectral decay to ensure that its 0ms at all frequencies from 20hz to 20khz. I've

What is oms?
(Is that 0 milliseconds?)

I do not think that we can apply an impulse to a system and get it to decay instantaneously unless we have zero output impedance, which a passive crossover  sort of gets in the way of.

The spectral decay is amplitude based in frequency versus time.
So yes it is a time domain based description, but it is shown in a PSD tyle of frequency response.
Is there a phase or complex component lurking around somewhere?

 

Lets assume that we have two speaker, both with 0 msec of decay.

Are there other measurements that would inform us of whether one is better than the other?
Say ones that included some idea of phase or time domain response (without frequency response), or do we just use frequency response?