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Multi-Way Conventional loudspeakers with crossovers

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Old 15th January 2020, 05:48 PM   #271
mark100 is offline mark100  United States
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Hi Peter,

That all makes sense, thx.
I had already started playing with lower sloped crossovers, given the dcx464's wider overlap. And may end up closer to 4kHz, it seems.

I know second harmonic is supposedly less offensive, and i see how it dominates the two CD's tests i made.
Yes, it would be nice to be able to make some distortion tests made off a signal more closely aligned with music than swept sine.

The THD measurements were more about curiosity than anything else, although i truly would like to know if THD can be heard.
Listening though Art's extensive test files now.

I may be just about done traveling this THD trail....
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Old 16th January 2020, 12:33 AM   #272
Peter Morris is offline Peter Morris  Australia
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Quote:
Originally Posted by mark100 View Post
Hi Peter,

That all makes sense, thx.
I had already started playing with lower sloped crossovers, given the dcx464's wider overlap. And may end up closer to 4kHz, it seems.

I know second harmonic is supposedly less offensive, and i see how it dominates the two CD's tests i made.
Yes, it would be nice to be able to make some distortion tests made off a signal more closely aligned with music than swept sine.

The THD measurements were more about curiosity than anything else, although i truly would like to know if THD can be heard.
Listening though Art's extensive test files now.

I may be just about done traveling this THD trail....
There is a masking effect in our hearing; they take advantage of it in data compression for MP3 etc. The tones that are masked don't need to reproduced and can be discarded - less data to record ... in terms of distortion it matters how close it is to the main signal and at what frequency the distortion occurs. i.e. second harmonics are more easily masked than others.
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Last edited by Peter Morris; 16th January 2020 at 12:42 AM.
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Old 16th January 2020, 06:13 AM   #273
manninen is offline manninen  Finland
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Quote:
Originally Posted by mark100 View Post
Yeah, 10% is kinda an industry standard huh?....
Industry standard for scattering birds from airport

Overview
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Old 16th January 2020, 09:35 AM   #274
jo bg is offline jo bg  Italy
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Very interesting comparison, thanks.
Maybe this has been already mentioned, What Is the exit angle of this drivers?
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Old 16th January 2020, 11:11 AM   #275
kipman725 is offline kipman725  United Kingdom
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Quote:
Originally Posted by manninen View Post
Industry standard for scattering birds from airport

Overview
The 4599ND has two most outstanding features:

It is the loudest audio transducer ever made
The frequency range is optimized for human voice

These capabilities make it best suited for:

Communication devices for long distance
Security systems
Emergency devices
Mass notification systems
Systems for scattering birds from airports
Marine applications
Military and police communication system
Noise cancelation systems
High End Audio Loudspeakers

If you compare it to the BMS4592ND-mid-8 on the same horn it has more output, ~-6dB harmonic distortion and a smoother frequency response. I guess the only disadvantage if you wanted a dedicated mid-range driver is the cost!

http://www.bmsspeakers.com/fileadmin...ta_2012-01.pdf
http://www.bmsspeakers.com/fileadmin...reliminary.pdf

I wonder how these drivers (coaxial and dedicated midrange 2" throat) compare to the midrange specific drivers from community that had a 4" throat?
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Old 17th January 2020, 03:55 AM   #276
Peter Morris is offline Peter Morris  Australia
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Quote:
Originally Posted by kipman725 View Post
The 4599ND has two most outstanding features:

It is the loudest audio transducer ever made
The frequency range is optimized for human voice

These capabilities make it best suited for:

Communication devices for long distance
Security systems
Emergency devices
Mass notification systems
Systems for scattering birds from airports
Marine applications
Military and police communication system
Noise cancelation systems
High End Audio Loudspeakers

If you compare it to the BMS4592ND-mid-8 on the same horn it has more output, ~-6dB harmonic distortion and a smoother frequency response. I guess the only disadvantage if you wanted a dedicated mid-range driver is the cost!

http://www.bmsspeakers.com/fileadmin...ta_2012-01.pdf
http://www.bmsspeakers.com/fileadmin...reliminary.pdf

I wonder how these drivers (coaxial and dedicated midrange 2" throat) compare to the midrange specific drivers from community that had a 4" throat?
The problem with 4599 is finding a VHF driver that will keep up - I was looking to build a super verion of my PM90/60 with the 4599 but I could not find a suitable VHF driver that could match its output.
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Old 17th January 2020, 08:50 PM   #277
mark100 is offline mark100  United States
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Quote:
Originally Posted by weltersys View Post
Pano's explanation of the tests in post #23 of the High Frequency Compression Driver Evaluation thread is helpful for "digestion" ;^).


Hi Art, yep, Pano did (always does) do a good job of explaining.
I understood the test quick enough...although it did take a little to figure out the filename code structure...but like you said, it was all there on the first page.

If I've heard any difference on the test tracks i've listened to, it's not any I'd be willing to bet i could hear in a double blind. Even pulled out the Stax phones to give a best listen...

So far, it's just been the music tracks for the two bms and the EV.
I went straight for the uh-oh 1Ap1763, figuring if that one didn't sound strained in comparison, none would

Very nice work
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Old 18th January 2020, 01:01 AM   #278
weltersys is offline weltersys  United States
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Quote:
Originally Posted by mark100 View Post
If I've heard any difference on the test tracks i've listened to, it's not any I'd be willing to bet i could hear in a double blind. Even pulled out the Stax phones to give a best listen...
Thanks for listening and commenting!

While conducting the HF driver tests, I thought that the distortion at high levels sounded quite horrible, though in retrospect, seems most of the discomfort was in my own hearing response- there is a fairly hard SPL limit in the upper range that sounds bad whether clean or distorted when my ears are “fresh”.

The “too bright” sensation at louder levels which seems contrary to the equal loudness contours that flatten out with increased SPL may be due to the manner in which hearing TTS (temporary threshold shift) occurs.
TTS is the reduced sensitivity to noise after exposure to loud noise, it’s temporary effect diminishes after time in a quiet environment.
Evidence of TTS is apparent when you get into your car the morning after coming home from a loud concert the night before, then must turn the stereo down to half the level that seemed “normal” the night before.

William Melnick has presented some evidence that indicates TTS is less when exposed to loud low frequency <125 Hz than higher frequencies.
With loud music played back with a low frequency “haystack” of +10 dB or more below 125Hz, the TTS threshold won’t “kick in” as hard, fast or with as deep of a reduction as it would from the same SPL at high frequencies. As SPL increases, TTS reduces sensitivity to the HF, but at some point your threshold of pain (or annoyance) is reached, and you will desire protection from the offensive “too bright” high frequencies.

Looking at Melnick’s charts, we see as much as 20dB shifts from 95 dB SPL of 1.4-2kHz noise, while increasing the level to 108 dB with 500-710Hz noise reduces TTS to about 10dB. The range at which TTS between subjects is also quite a lot, “too loud” is very subjective.

The decay time from TTS can be as much as 24 hours, it can be quite a while before your hearing normalizes after exposure to loud music or noise, what sounded good (or bad..) yesterday might be quite different after a break, and at a different level.

Art
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File Type: png Growth and decay of TTS.png (92.0 KB, 43 views)
File Type: png W Melnick,TTS & Noise.png (653.9 KB, 45 views)
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