We can not hear group-delay under 100Hz?

Group delay Problems

Phase Distortion Vs frequency interferes with the requirement that all the signals of different frequencies are required to arrive at the end of the pipe together in time.

Consider these items:

(1) Low frequency speakers are the most corrupted element in the loop. You can research this in the Free Wikipedia Dictionary.

(2) I am not Pushing Audio Cables, but history speaks well on this item.

"Interconnect cables and speaker cable phase corruption"__ according Mr. Bruce Bresson, CEO of MIT / Musical Interface Technology inc, owner of all the important Patents on cables in the world__ states in his first patent: "From 20,000 Hz all the way down to the lowest audio frequency of interest aka, 20 Hz, the magnetic field attending the audio current in the cable conductor Sinks toward the interior of the conductor" which by definition is:increasing inductance inversely proportional to frequency or increasing Group Delay with decreasing frequency.

MIT's first solution was to use a "hollow thin wall flexible pipe" which was executed by wrapping thin wire side by side around a Teflon rope some ten feet long, which he licensed to "Monster Cables inc.

This approach worked quite well down to some 300 Hz, His next patents extended the low frequency group delay with various networks.

Legend has it That "Transparent Audio Inc" added a chunk of Ferrite Magnetic Inductance Properties at the end of the Monster Cable with considerable success.

(3) Vacuum tubes are superior to solid state because there is no impediment to the Emission in the Vacuum, especially tubes with heavy filaments like a Type RCA 26 tube & the type 845 or the Western Electric 300-A & 300-B which have filaments of 11 layers of lamination construction good for 10,000 hours.

(4) Every component in the audio chain damages Group Delay including hook-up tiny conductors in amplifiers. I have a 1989 Sony TV with a tiny 2 inch square Chip 10 watt amplifier in which the chip components are inter-connected with 1/8 inch gold ribbons__ this amplifier offers superb audio sound and measures quite well for phase linearity and phase distortion__ impeccable Group Delay despite the solid state active devices
 
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Guys ,Just found a link pls read this, Do read it from first page. I am putting link for 4 th page which is conclusion page.

group_delay_4

Thanks for posting the link to this article. Interesting simulation based optimization based on the extrapolation of certain listening tests from 500Hz and scaling with wavelength period. I have played with similar optimizations and wondered how much bass I should give away and how much group delay at 20 Hz is audible in a system with and F3 10 or 20 Hz above that anyway. Good point about the implied THD tradeoff with cone excursion.
However - it would be nice if the following statements (pg 4) were linked to more specifics on the listening tests done: "
In researching this dissertation, I was unable to ascertain a finite limit for acceptable group delay in speaker
design. It appears to be relatively indiscernible, especially when listening to musical content (as opposed to
test tones), and some studies indicate its effects to be partially masked by the reverberant field of the room." Any more info on this?
thx

 

jim1961

Member
2012-04-16 4:59 pm
Texas
If low frequencies are dominated by the room response, and the delays associated with it, then when we are talking about GD or EGD, we are in great measure talking about the room at least as much as the speaker, right?

So if we are trying to determine what the good, the bad, and the ugly are in terms of measurement data, we are talking about those measurements taken at the listening position, right?


10 06 14 gd r 2.jpg

Here is what I am measuring. My question is how big an issue the 35-40hz region is in regards to GD and/or EGD. This measurement is taken at the listening position, the right channel driven and measured only with 1/24th oct smoothing.
 
For yus guys who ascribe 'fast' or 'slow' bass to ported or sealed boxes etc, may I suggest you check this using Blind Listening Tests. Just my $0.02 :)

Where can I find these "tests"?
In 20+ years of audiophilizm I've never once saw a double blind test.

Just heard: this takes the veils off, that takes the veils off, here's graphs with lines on them. If you don't believe me you're crazy just like me and most audiophiles, so welcome to the club :grouphug:

Why are we talking about the room and roll-off?
There's always rooms and roll-off?

It's like some one saying something is genetic when you have a medical problem.
D00d! I know it's genetic, everything is genetic, stop confusing the issue.

Also this thread should be like 1 page long, instead of 1000 theories.
Either it flies with experimentation or it doesn't.
Doesn't matter what your theory is.
 
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For example, some one asks: how does this tire compound preform vs this other one?

You don't answer with:
Well depends on the size of the tire, the weight of the wheel, the weight of the car, the type of road, the weather, the temperature, who made the tire, was jim working that day or did sally make it.

Same everything:
Does 10 ms group delay at 33 Hz sound different than 20ms group delay?
Is it possible for everything else to be the same and only group delay and maybe phase to differ?

I don't care about the room. I'm going to be listening to the speakers in a ball of gas in outer space, if you want.
 
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