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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
kenjit OP
1,771 posts
 

@timlub feel free to correct me if you think I do not have a correct funamental understanding

timlub
2,039 posts
 

You stated that it tells us "how fast a speaker responds:.

The motor of a speaker directly affects the speed in which a driver reacts.

What you are call ing time domain response is in direct correlation to drivers alignment combined with each drivers natural rolloff and crossover components used.

On QTS, you did quote the textbook response that qts is a summed combination os qms and qes, but you still show no understanding of what that means. 

Mechanical q can be affected by mass, electrical q affected by electrical transfer in the motor and induction of the coil.  

The combination QTS is a direct correlation of how this Zdriver will work in a sealed box vs a ported or vented.  Any driver that has a qts below .4 ish will not go down in a sealed box and any driver with a qts below .25 or so will have a problem going down in any box.  As QTS rises..... .3 to .4 do a very good job of being used in a ported or vented box,  a QTS of .4 to .5  ride the line that can be used in ported or sealed and .5 and above will work well in a sealed box.  Combine this with VAS,  the drivers equivalent air pressure tells us what size of box this driver will work in.  

 

kenjit OP
1,771 posts
 

Why focus on the motor alone? it can be also due to the input signal current, the mass of the driver etc

What you are calling time domain response is in direct correlation to drivers alignment combined with each drivers natural rolloff and crossover components used.  

The cabinet also rings. yes crossover circuitry can also cause ringing. So how do you stop it? Do you have any answers?

timlub
2,039 posts
 

You know Kenji,  you are one person that I wish that i would have never responded to when contacted.  I tried to help you,  you tore me down,  I still tried to help,  you argued and now, you post that I don't know anything about your room or your boxes..... Ok,  I am done with you..... You know, I can post our conversations that you sent to my home.  I can tell others what drivers you use, that they are put in MDF with a flat front, that they are not countersunk that they are forward firing with no tow, that they are 7 to 8 ft apart, (you didn't want to measure) and are currently set up in a triangle..... No,  your right, I didn't ask you anything about your current speakers or set up.  Consider your email blocked from my home.  

jasonbourne52's avatar
jasonbourne52
2,863 posts
 

Peter Walker invented the first time-coherent speaker back in 1955! It is the Quad 57 - named for Peter's company and the year the first commercial ones appeared. Still a landmark product!

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