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Deleted member 375592
Yes,
The solid lines - non-linear products, RESiduals from linear filtering.
The dotted lines: the microphone signal
The dashed lines - the ratio of microphones to the non-linear products
The colors represent varying HPF from 50 to 300 Hz
foAX80 is a code helping me to recover what was going on there (FOcal, Audiotechika mic, X=measurent mic, 80 dB SPL @1m)
One line conclusion - IMHO, 2*Fs is indeed a good ROT.
That's why I tend to get the impedance linearised first, before the filter & any necessary padding, with the latter providing sufficient adjustability for fine-trimming without affecting the transfer functions.
Oh? I thought their claim to fame was perfect impulse response or something. If they aren't getting that, why bother stressing all the drivers?? 🤣
I wasn't a fan of the D28 at all. The D21 was good though. The D28 sounded dark and not nearly as clean as the D2904-9500 Scanspeak or even the cheaper Vifa D27TG35(45). It was disappointing the claimed perfect transient response wasn't so perfect and many people who bought Dynaudio speakers listened to test tracks and sine waves more than music.
Dunlavey had a better implementation of 1st order filters, but they also did some sketchy stuff. The tweeters were so stressed on these speakers that I bought a big tray of Vifa D27TG45s to have enough on hand for field repairs. They did sound very good though with the right amplification and source.
Dunlavey had a better implementation of 1st order filters, but they also did some sketchy stuff. The tweeters were so stressed on these speakers that I bought a big tray of Vifa D27TG45s to have enough on hand for field repairs. They did sound very good though with the right amplification and source.
@YSDR Thats correct. You can remove the FF and it becomes a 27TDC which also measures the same as in the specs. Seas still uses solid VC lead wires in the 27 series tweeters which is surprising, as even the cheap Chinese made Peerless have braided leads. The back chamber design on the Seas 27s resonates noticeably at 2k and this also shows up as a small bump in some spec sheets.its likely to minor to notice with a higher crossover but you can hear it with lower than 2.5k HP on some female vocals.
Apologies for the typo: use the correct H1211. The suffix should have read 'TDF'. Sorry for any confusion.
Not particularly surprising: those drivers are pushing 25 years+ old now, and the individual models have never been updated AFAIK. To their credit, I recently had a pair of H1189s through here: for practical purposes they measured identically to a pair I tested back in '07. No noticable issues at 2KHz from a chamber resonance from either of those from my measures; I can't see any in Yevegeniy or Zaph's either. It's not the best chamber design & that shows in the impedance but FR and (impressive) HD around there are well behaved for units of their type / age. Not a first choice for me (I prefer rigid dome designs) but in fairness, I'd say that unit still holds up well for what it is, ditto for its H1212 alloy dome stablemate, and I do like the relatively narrow surround rather than the recent fashion for oversized roll types.
Not particularly surprising: those drivers are pushing 25 years+ old now, and the individual models have never been updated AFAIK. To their credit, I recently had a pair of H1189s through here: for practical purposes they measured identically to a pair I tested back in '07. No noticable issues at 2KHz from a chamber resonance from either of those from my measures; I can't see any in Yevegeniy or Zaph's either. It's not the best chamber design & that shows in the impedance but FR and (impressive) HD around there are well behaved for units of their type / age. Not a first choice for me (I prefer rigid dome designs) but in fairness, I'd say that unit still holds up well for what it is, ditto for its H1212 alloy dome stablemate, and I do like the relatively narrow surround rather than the recent fashion for oversized roll types.
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Phase alignment. Dynaudio run 1st order filters with all-pass delay lines on the HF (& mids as relevant) to compensate for the acoustic centre offsets on a flat baffle & get the FR & phase lined up to the target slopes, rather than using mechanical offsets (stepped / slanted baffles etc.) for the same object. They've occasionally been known to use an offset on the vertical plane to help achieve that too, although that comes with the usual caveats. Lots of impedance compensation etc. as you'd expect. In fairness, acoustic LR2 requires the same in most similar cases assuming flat baffles & the usual Z-axis offsets. For regular cone & dome types, I tend to see it as a solution in search of a problem, but different strokes & all that. And you do feel very manly, knowing you have implemented all pass (ladder / trellis) delay networks in your design, which so many other plebs see as being far too advanced for their limited sensibilities. They may even start to call you 'Maestro' when you present designs in future.
That last bit is fiction. At least, I hope it is.
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