From time domain data from European tests on a DD66000
From time domain data from European tests on a DD66000
Hey Rob,
Given the interest and intrigue on the Urei monitors it would be interesting to examine the time domain measurements of your Urei centre channel and compare to the M2 as a baseline. It would also be interesting to compare the impulse of the woofer and the horn to see if in fact they are time aligned at the crossover point?
I would love to see the impulse response of a UREI coax... I'll bet it is not truly time aligned. I would expect that it is improved over the original Altec/JBL, but I doubt they were able to nail the impulse response with simple passive components.
Widget
Hey WidgetOriginally Posted by Mr. Widget
Hope you are high and dry! I have the driver and crossover but no cabinet and don't have one that would accommodate and E-145 with a 2425S hanging off the back. So lets hope someone else can post it. Curious as well !!
Rob
"I could be arguing in my spare time"
I've got a spare 811C you guys can test, you just have to pay & arrange for shipping or come to Michigan.
I've got a spare 811C you guys can test, you just have to pay & arrange for shipping or come to Michigan.
If you have a Laptop you can do with some assistance.
Well, it's not likely to be good by today's standards but I'd be curious to see how different the UREI is from the Altec 604-8g, which I think is the model UREI used when they started. I know eso has some 811b(?) but don't know if he has measurement tools, and may have 604-8g? Toddalin has Big Reds (604-8g?) but they likely have the Soundlabs(?) crossovers which might have time alignment(?) not Altec crossovers.
And I'd really like to see a waterfall of the 2425h with an original aluminum diaphragm and the later titanium replacement. Have to believe the ringing in the titanium diaphragms is wicked.
Maybe. But it’s probably appropriate to keep opinions out of this thread. It’s about the facts.
Last edited by Ian Mackenzie; 02-05-2024 at 06:18 PM. Reason: Changed meaning of post
Hello Rusty
I have been going back to look at older measurements. I have darn near all of them saved since I first started using Clio. So I looked around and found a couple of 2425/26 measurements on the 2344 and 2370 Biradial. They look reasonably clean last octave compared to what some of the drivers in the presentation look like.
These are Ti never had a pair of the original aluminum ones.
Take a look
Rob
"I could be arguing in my spare time"
:-D Hey, thanks Rob. You are the keeper of the technical files. I'm surprised both are so clean at high frequency as you mentioned, but that first one (2344?) looks pretty rough in the 1khz-2khz range. I should have added a quote to that last post as my curiosity about the 2425 is time alignment and waterfall mounted as the 801. Now I wonder if it's not high frequency ringing but rather closer to the crossover point?Hello Rusty
I have been going back to look at older measurements. I have darn near all of them saved since I first started using Clio. So I looked around and found a couple of 2425/26 measurements on the 2344 and 2370 Biradial. They look reasonably clean last octave compared to what some of the drivers in the presentation look like.
These are Ti never had a pair of the original aluminum ones.
Take a look
Rob
I have a pair of 2425 here and Dhar has a 3d printed Joseph Crowe 1" exit horn we should try getting some measurements on. Might be surprised. If anybody in the DMV has an 811 to measure I'm sure he'd be happy to do it.
Hi Rob,
Under what conditions did you test those drivers ?
Were those measurements gated and what distance?
Looks like you smoothed them 1/12 octave.
I have been trying to obtain some detailed information from the presentation. Attached are some files comparing the titanium and beryllium diaphragms. (18Sound)
* Most of the B&C HF compression drivers are for OEM customers using line arrays.
* B&C HF drivers are designed for maximum efficiency and output in pro applications
* Specific B&C HF drivers are designed for studio monitors
* ln some instances in the B&C drivers the hf resonance is designed into the driver at the request of the OEM client @ 15 khertz ( see the presentation).
* While not scientifically validated it’s the longer time domain resonances that can be detected by the ear/ brain above 10,000 hertz. For example a 15000 hertz frequency has a time domain duration of 0.15 of a ms per wavelength. If this takes 4 ms to decay then there are 26 cycles during that time period. That’s what’s detected as a spatial information. Four ms is the equivalent of a 576 hertz wave length.
18Sound are a premium brand now owned by B&C loudspeakers
* aluminium, titanium and beryllium diaphragms are available across the range
A few general trends
* An HF compression driver that has an extended non normalised above 10,000 hertz on a snap shot FR curve will have resonances with longer time domain.
* An HF driver (including beryllium) that doesn’t have resonances will require greater EQ to obtain a normalised response. (Annular diaphragm drivers are a different case)
*Beryllium diaphragms are very costly.
Attached below is a screenshot of the 18Sound HF driver range.
Hello Ian
The gate times are right on the graphs. Smoothed as little as possible in Clio 7 and also what makes sense. Distances?? Not sure those are at least 12-15 years old.
Rob
"I could be arguing in my spare time"
If you want that as a reference for comparison then it needs to be validated. Otherwise it’s misleading.
On the basis of you’ve posted if it was true then why bother with beryllium??
I think there needs standard for the rise time and the other settings
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