I also tried a crossover variation using the technique Joe Rassmussen employs in the Elsinore, a very low order blend, steepening up an octave below the crossover point with tweeter inverted so that as the tweeters impulse rises back up it meets the woofer. The M74P's twin resonant peaks might make this difficult in real life, or maybe not. I am interested in testing differences in vertical directivity in the next few designs I make. The six pack image also has the Horizontal ERDI, to show that it is the vertical response that causes the DI to vary.
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Did you ever do a good comparison? So you don't know which speaker is playing (at least as good as possible - we are pretty good at hearing horizontal differences)?
This is also what I hear with hard dome tweeters. And some overdo this in my opinion.
Hi @fluid , it's been a while since you have the M74P. I would like to hear you opinion on this mid driver as compare to the other version of the M74 series. I am currently using the Satori Textreme MW16TX woofer with the TW29TX tweeter, personally I find this combination sounds a bit too clean and clear to my liking, hoping to find a mid driver that can sound more "organic". I am hoping one of the M74 series can help with that.
I don't yet have an opinion on the M74P and I have never heard or used the other versions so I doubt that I will ever be in a position to help decide between them based on personal experience. I do have a pair of T25B on their way to me now. Ever so slowly moving towards making an actual speaker with them
The M74S doesn't sound "soft"! There are a lot of details still with this midrange!
I had the direct half blind comparison to M74A, both corrected to 0,5dB and in their dedicated frequency range. The difference is not like night and day, with some songs you barely notice it. But over all the S version is more "friendly" and takes the edge from the source material. Good when you want to just listen to music. The A version is very honest and this gives a feeling of "truth" and a very natural reproduction. I have the feeling I can "trust" what I hear and that's important in an professoinal environment.
(be aware - I don't listen to these drivers in fullrange cause that makes no sense. When doing so you will come to totally different conclusions!)
The membrane of the S is really thin and light and not too stable - it's designed for a sound goal. ATC dome is more rigid. But the suspension probably has more losses? I would GUESS it will sit in between soundwise but also could be similar to the S.
I will try and do a comparison of the M74B and A in the next 2-3 weeks - when somebody sends me a M74P ...
I had the direct half blind comparison to M74A, both corrected to 0,5dB and in their dedicated frequency range. The difference is not like night and day, with some songs you barely notice it. But over all the S version is more "friendly" and takes the edge from the source material. Good when you want to just listen to music. The A version is very honest and this gives a feeling of "truth" and a very natural reproduction. I have the feeling I can "trust" what I hear and that's important in an professoinal environment.
(be aware - I don't listen to these drivers in fullrange cause that makes no sense. When doing so you will come to totally different conclusions!)
The membrane of the S is really thin and light and not too stable - it's designed for a sound goal. ATC dome is more rigid. But the suspension probably has more losses? I would GUESS it will sit in between soundwise but also could be similar to the S.
I will try and do a comparison of the M74B and A in the next 2-3 weeks - when somebody sends me a M74P ...
Whenever you get to measure it, so you mind taking diagonal polars?
ie. Horizontal polars 0-90, then rotate driver 45 degrees, and take horizontal polars again.
It would be interesting to see the anisotropic behaviour of weaves like Textreme.
I can contribute and measure anisotropic behaviour of Kevlar and fibreglass based weaves.
Reference:
https://www.klippel.de/fileadmin/_migrated/content_uploads/KLIPPEL_Cone_Vibration_Poster_01.pdf
ie. Horizontal polars 0-90, then rotate driver 45 degrees, and take horizontal polars again.
It would be interesting to see the anisotropic behaviour of weaves like Textreme.
I can contribute and measure anisotropic behaviour of Kevlar and fibreglass based weaves.
Reference:
https://www.klippel.de/fileadmin/_migrated/content_uploads/KLIPPEL_Cone_Vibration_Poster_01.pdf
TL;DR: it’s probably not measurable by spinorama techniques, which is by design. One of the advantages of flat tow composites is that the engineers can push the nasty frequencies much, much higher, typically higher than we can hear.
Long version: I suspect “macroscopic” measurements wouldn’t be able to resolve anisotropic effects of flat tow composites. The modal analysis of Textreme diaphragms typically show the node spacing to be on the order of the unidirectional tape widths, which can range from 6.35 mm (0.25 in) to over 50 mm. Typically, you would aim for using wider tapes in order to minimize the number of tape edges, where the composite would be weaker, but narrower widths to have more degrees of freedom to control the mode shapes and frequencies. It looks like Satori is using 25-30 mm tapes, and if the same is true for this driver, there would be roughly ~3-ish +/- 1,000,000 nodes across the width of a 74 mm dome, meaning the modal frequencies are potentially/likely/roughly/handwavingly (apologies, I can’t to Fourier analysis in my head) much, much higher than the pistonic resonance frequency, ~12.5-13kHz, and the corresponding interactions between the primary signal and modal resonances are on the order of sub-millimeter wavelengths, which is why they use optical methods (e.g., sharks with freakin’ lasers) to make measurements.
Sorry for the run on sentence.
Long version: I suspect “macroscopic” measurements wouldn’t be able to resolve anisotropic effects of flat tow composites. The modal analysis of Textreme diaphragms typically show the node spacing to be on the order of the unidirectional tape widths, which can range from 6.35 mm (0.25 in) to over 50 mm. Typically, you would aim for using wider tapes in order to minimize the number of tape edges, where the composite would be weaker, but narrower widths to have more degrees of freedom to control the mode shapes and frequencies. It looks like Satori is using 25-30 mm tapes, and if the same is true for this driver, there would be roughly ~3-ish +/- 1,000,000 nodes across the width of a 74 mm dome, meaning the modal frequencies are potentially/likely/roughly/handwavingly (apologies, I can’t to Fourier analysis in my head) much, much higher than the pistonic resonance frequency, ~12.5-13kHz, and the corresponding interactions between the primary signal and modal resonances are on the order of sub-millimeter wavelengths, which is why they use optical methods (e.g., sharks with freakin’ lasers) to make measurements.
Sorry for the run on sentence.