HF driver comparison 23744 vs 34647

I finally landed some nice 802-8G HF compression drivers with the "lite" diaphragms part # 23744, so I thought I would do some measurements and see if there is a quantifiable difference between the lite frams and the replacement frams that came along shortly after (part # 34647).

To conduct the tests, I wanted to control as much variability as possible, so I used the same 802-8G driver for all measurements, and swapped out the frams only. I took measurements from exactly the same positions, using the same amp, same levels, etc. I measured using three different horns that I have on hand: the MR931-12, 811, and 511.

Here's the 802-8G I used. Great condition, very clean:
http://imageshack.us/a/img94/2340/img0449hd.jpg

http://imageshack.us/a/img195/6338/img0450jm.jpg

And the two frams used for all the tests. The 23744 lite:
http://imageshack.us/a/img692/3216/img0451fw.jpg

And the 34647 (slightly dimpled):
http://imageshack.us/a/img442/1529/img0452gf.jpg

Here are the measurements for the 34647 fram on all three horns:
http://imageshack.us/a/img593/5812/8028g34647.png

And here are the measurements for the 23744 on all three horns:
http://imageshack.us/a/img688/5825/8028g23744.png

Here is the fram side x side compare on the 511 horn:
http://imageshack.us/a/img577/8572/8028gframcompare.png

Now, put one of each diaphragm in a separate driver and horn combo and play some mono music though them at the same time and see if you can hear a difference.

Good info, thanks. The light fram is essentially better everywhere.

So Volvo, what is your point?
Just curious.

Ron

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...................see if there is a quantifiable difference

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Pretty difficult to do since used diaphragms don't have odometers or hour meters.

Certainly a difference is shown in your measurements(and that's not unexpected). But, there are no baseline or control samples to conclusively prove that the measured differences are the result of and limited to their manufacturing or material differences.

For the data to be considered empirical, you would need to start with multiple NEW diaphragms of each type under strict control, not diaphragms with unknown hours and magnitudes of use.

Just my .02 y'all understand.....................

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Originally Posted by RonSSS

Good info, thanks. The light fram is essentially better everywhere.

Ron

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If "better" is interchangeable with "more efficient" then yes. To me everywhere would include high volume tests, where the light fram will likely distort first. I does seem to have slightly better 9-12kHz response. I would also expect better transients, as a lighter mass accelerates quicker.

I suspect in an A/B on delicate tracks, like acoustic stuff, the light fram would be readily identifiable.

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Originally Posted by bowtie427ss

For the data to be considered empirical, you would need to start with multiple NEW diaphragms of each type under strict control, not diaphragms with unknown hours and magnitudes of use.

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no arguments, sir. I make no claims, simply wanted to get some data out there that was collected in a reasonably controlled manner. I also measured the same frams in a 908-8A driver, and also used a new, modern driver/fram in all three horns as a comparison point. I can post some of that data if there is any interest.

Another thing that I can do is try the same tests with the other two frams of the same part#, to see if there is any meaningful variations from fram-to-fram. But yes, it would be great to get new frams to use in this testing - maybe John would mail me his :D

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Originally Posted by Alien_Shore

no arguments, sir. I make no claims, simply wanted to get some data out there that was collected in a reasonably controlled manner. I also measured the same frams in a 908-8A driver, and also used a new, modern driver/fram in all three horns as a comparison point. I can post some of that data if there is any interest.

Another thing that I can do is try the same tests with the other two frams of the same part#, to see if there is any meaningful variations from fram-to-fram. But yes, it would be great to get new frams to use in this testing - maybe John would mail me his :D

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Don't get me wrong. I've heard enough of both that your measurements pretty closely show what i believe i hear, and i think there will be a consensus among those who have also had the opportunity to listen to multiples of both. Now if we could just get the fellas to pony up and break the seal on a couple of their NOS 23744's and send them to you for evaluation..................... ;)

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Originally Posted by RonSSS

So Volvo, what is your point?
Just curious.Ron

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I just meant that it all looks great on graph paper, but how do they sound side by side. Throw in a symbiotic and a pascalite for a total comparison. :)

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Originally Posted by VolvoHeretic

I just meant that it all looks great on graph paper, but how do they sound side by side. Throw in a symbiotic and a pascalite for a total comparison. :)

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Interesting that you bring this up. I am reminded everytime a measurement thread pops up, that frequency response measurements while useful and informative, don't tell the whole acoustic story of how something "sounds". You cannot measure "timbre" for instance.

Volvo, thanks.

When I said better, look at the graphs, it is better. Also smoother. The interesting thing is the bump at approx 12khz. They will sound extended.

I've done similar measurements, but it's been a long time ago. I saw similar things.

As far as swaping frams out and listening, I never had enough drivers to do that quickly. I know my brain will forgrt in the hour or so it takes to carefully swap the fram.....so not real sure I'd immediately go "WOW"...that one is better.

Again, good info.

Ron