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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
holmz's avatar
holmz
2,328 posts
 

 

Now time domain should relate to a wide band response. If for rxemple you have a two ways, the two point of emissions should arrive at the ears at the same time, so they are in phase and time correct. But it’s important to consider the behavior of the cross-over (inductive and capacitive parts. 6db slopes allowing for a better time domain behavior (less phase rotations) than 12 or 18 db slopes.

The position of the tweeter and woofer have to be such that cross-over frequency and behavior are taken in account. Introducing a square wave and measuring it through a microphone (able to reproduce it) can help to finalize the position of the tweeter. The ear is very sensible to time domain by the way

@armagedon36 ^agree^
We could break it down into before and after…

  • With “before” being the launching of the acoustic field off of the transducer, which you are mentioning is best when it is faithful to the input signal (e.g. square wave).
  • and the “after” being any resonance or ringing after the signal should have ended.

But… the OP at one point was talking more about cabinet ringing after the fact, and having a death grip on the driver with aa QTS=0 and did not seem to care about the “before” part.

At least in chronological order, worrying about what happens later, is a bit
“after the fact”… as you implicitly pointed out.

It is probably best to start off right, and not have it go all down the sewer with cabinet ringing and resonances later. (IMO)

 

But we do not know what the OP was thinking as they went silent pretty quickly.

jerryg123's avatar
jerryg123
3,429 posts
 

Nothing from @kenjit is a must read. 

perkri
908 posts
 

@erik_squires 

 

Thanks for that! So happy to hear Fritz is a nice as I have imagined from everything I’ve read. I’ve considered reaching out to him, but never been comfortable asking technical advice from a manufacturer/anyone in the industry  I don’t know. 
 

As far as caps in his circuit, I was going by the links and what he wrote about his crossovers. I’d be curious what purpose a cap would serve in a crossover beyond protecting the tweeter. Unless it’s being used in a Zobel network on the woofer?

@timlub 

While it works like a series crossover, don’t know I would refer t9 it as simply a series crossover. If it were, the designer would not have been able to get a patent on it. I’m a big fan of the approach. Have a way to go with getting a better understanding of its implementation (which is why I have wanted to reach out to Fritz), but seeing as how there is a commercial product I’m working on at the end of this, didn’t feel it was appropriate. 
 

Too bad this conversation has to happen in between the kenidjits ridiculous self aggrandizing rhetoric…

 

erik_squires
16,144 posts
 

I was going by the links and what he wrote about his crossovers. I’d be curious what purpose a cap would serve in a crossover beyond protecting the tweeter. Unless it’s being used in a Zobel network on the woofer?

@perkri 

Caps and coils are fundamental to creating high and low pass filters. Here’s a post I wrote a long time ago that may help you, though it covers the more common parallel crossovers:

 

I know nothing about Fritz, and any patents or licensing involved, but patent reviewers are not omniscient or even domain experts. It is not that hard to patent BS or to create a patent which is a duplicate of another patent just reworded.

erik_squires
16,144 posts
 

Also here:

 

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