Just my own testing, sorry I didn't save it. 3rd order was below 65dB and 5th order below 75dB throughout the midrange. This was at 95dB and 1' mic distance.
In principle, the front part is removable as it joins to the rear part with four screws, the heads of which are visible from the back. Such a design solution makes it easy to provide the speaker with any waveguide of your own design instead of the original flange. A useful option, as it helps to expand the applicability of the midrange, however, there is one "but" that I was strictly warned about - due to the assembly process and construction features, any attempt to remove the front part of the flange in the series model will cause a misalignment of the moving system. Therefore, to be on the safe side, you must contact a manufacturer and order this option in advance.
So, guys, before turning any screws, I advise you to think three times and propose to consider this option as undocumented, but potentially possible.
I can't add more than that.
I think from the video I watched in Chinese it was about the dome oscillating and not wobbling out of control which happens with domes -so it maintains its form better. I will see if I can find the video again -not easy because I was ploughing through obscure Chinese forums.
Take mind that at 2.83V M74B makes 98db. For a 90db it needs just little over 1V. HD is not high in any kind of way. 5khz 3rd HD peak can be removed with right kind of analog crossover implementation. And most important, waterfall is very clean and IMD is low. Bliesma M74B is true state-of-art driver.
Very good points. For my purposes (midrange between Purifi PTT6.5 and T25B) it would require a good bit of padding - so even lower distortion. Still the H5 peak at 3k, replicated in the H3 peak at 5k and the H2 peak at 4k strike me as indicative of some breakup that I, personally, wouldn't associate with a state-of-the-art driver. But, I could very well be wrong in that regard. I'm curious how one would remove these in the crossover (without impacting the FR)?
You're absolutely right about the waterfall and IMD. It seems I over-reacted. It's moot anyway as I can't afford the M74B and even the others are probably considerably outside my budget.
You're absolutely right about the waterfall and IMD. It seems I over-reacted. It's moot anyway as I can't afford the M74B and even the others are probably considerably outside my budget.
Please realize the CSD plots are only minimum-phase , they do not show the stored energy of the filter network ... once we had DAAS 32 / DAAS 4 USB and the ATB PC Pro by Kirchner Electronic in germany ... those real CSD plots show a complex image what's really going on but it's hard to judge them visually so they went out of favour ... the magic buzz was "dynamic measurement" around 10years ago ... so if your CSD looks nice it is not the full story!
Nice and long awaited measurements! Thank you!
Taking a M74B and a T25B crossed at 2k5, this could result in a max. 96dB SPL combo from 750Hz to >10kHz, if you put a constraint that THD must not exceed 0.3%. So then, this high quality 750Hz ... >10kHz passband system costs about $1000 and comes with potentially highly toxic Beryllium. I guess that a well designed ESL (or eventually a high quality horn system also?) might be capable of even lower THD figures at slightly higher SPL levels. At a lower price tag, and without problematic waste within 20 years. So I am very reluctant to follow this Beryllium hype.
Taking a M74B and a T25B crossed at 2k5, this could result in a max. 96dB SPL combo from 750Hz to >10kHz, if you put a constraint that THD must not exceed 0.3%. So then, this high quality 750Hz ... >10kHz passband system costs about $1000 and comes with potentially highly toxic Beryllium. I guess that a well designed ESL (or eventually a high quality horn system also?) might be capable of even lower THD figures at slightly higher SPL levels. At a lower price tag, and without problematic waste within 20 years. So I am very reluctant to follow this Beryllium hype.
You better check fact sheets about Beryllium toxicity. Beryllium is highly toxic when you breath it in, e.g. as a form of dust or vapor. Licking / ingestion is a secondary problem, such as diffusion intake through the skin.
I have. Explain to me how you get dust or vapour from the Be domes in speakers in normal use.
Note, not in their construction because the manufacturer should be following local OH&S procedures.
I know that designs using 6.5" mid-woofers and 1" tweeters are common, but I've typically (not always) found them to be compromised in regards to directivity and power response. I could put the T25B in a waveguide, but I would only do so if I could have a protective mesh over it and I'd be sweating bullets while doing so.
3 way speakers "always" have lower IMD than 2 way. And overall that makes cleaner sound.
I think you might be missing the point of what b_force said
The point (for me) is not that a 3 way has no benefit over a 2-way... Instead the point is that once a person has decided that they are building a 3 way, why use a single 6.5 inch driver for the woofer? There are a lot of very nice 8 inch woofers that can be had for less than $400.