Yes, the Hypex plate amps would be the most straightforward in terms of wires, clutter, etc. Working with their DSP seems to be a hassle to some, but could certainly be learned. I just wonder about the converters and that the amp sections are an older generation compared to what is available now. If Hypex were to update the amps or, even more so, if Purifi released plate amps with their amp modules it would be a no-brainer decision.
@witwald thank you for the sims. I agree that the Wom265_vKi-6 looks very capable in a vented enclosure. So good, that with the much better sensitivity than the PTT10 I almost went with them. In the end, though, I stuck with my plan for sealed. Partly, this is based on the idea of minimizing resonances as much as possible (including no ports), and also based on trying to make the build as "easy" (ha!) as possible, or at least avoiding things like tuning boxes, etc.
My thinking has been that the PTT10 is so linear above the 500Hz XO that the LP crossover shouldn't be too difficult (even for me!). I'm not even sure if notching the breakup will be required as the 5th harmonic of it (going downward) is above the XO frequency. If I get the level at crossover matched to the M74, then the wide baffle will have the baffle step at the Schroeder frequency of the room, 250Hz or so, then below that the room will dominate and I will manage it as part of my overall bass management strategy (the PTT10s and multiple subs, room treatment). My current speakers have ported 12"s tuned relatively high, so I actually anticipate more extension as I calculate that each PTT10 is capable of producing 95db at 20Hz in a sealed enclosure. So if I need a little boost at the very bottom I should be ok.
Thanks again for all the ideas,
Bill
Hypex will be releasing Fusion amps with nCoreX modules next year. That said, any improvements over the old nCore amps are likely inaudible. I am hoping remaining stock of the nCore fusion amps will go on clearance upon the release of the new version
And if Purifi ever make plate amps we will probably not be able to afford them anyway... 😁
The DSP software comes from thinking as a DSP programmer and not speaker controller. And it's not as stable as it should be. But when you have dialed your settings in everything is fine.
The plate amps get updated but not the D/A converters. And these are the limiting factor. Ideally you go digital into these (as any!) DSPs to avoid A/D conversion at pretty low levels and achieve the best dynamic range possible. Then you get about 115dB system dynamic range - that's hard to be topped with any other system and for sure better as every home cinema preamp + power amp.
I have recently heard a few newer and prototype class D amps. I am not sure which part of my varied listening experiences with these amps are derived from personal bias, expectations, mood, etc. Most seem to have great (amazing) command over the bass range. On the other hand, some seem to make the music be "alive" and "vibrant", while others seem sort-of clinical sounding. Nothing really wrong that I can describe. They probably all measure about the same.
Other folks seem to hear slight differences in DACs and such that I don't, but some amp/speaker combinations really seem to make the music more attractive to me than others. The few new/prototype amps I have heard were all played through the same speakers---some 12" ported Harbeths.
Last edited:
I would say a good class d amp does every range just about as well
My subjective experience has been that class d amps with pffb have all sounded pretty similar at lower volumes. I naturally preferred the more powerful amps as things got louder
There are some class d amps I would definitely describe as clinical. Icepower, Fosi ZA3, for example. It might be a coincidence that these amps lack pffb
The class d amps I've tried: Hypex Nilai, Hypex NC252MP, Douk A5, Icepower, Fosi ZA3, Wiim streaming amp, Aiyima A07, SMSL AL200 (meh), Crown XLS 2502 (good for subs..)
I am basically a class d convert at this point, but I had been using a pair of Classe DR8 monoblocks prior, which do definitely sound a bit more euphonic in comparison. I attribute this to the design philosophy of the designer of the classes, rather than anything inherent to class a/ab. Other class a/ab amps I've heard that were designed to be straight wire with gain, have sounded a lot like the best class d amps I've tried (usually minus the gargantuan power)
In my experience most of the best class d amps were designed to be straight wire with gain, which a lot of people don't vibe with, so the whole technology gets a bad rap
Last edited:
Finally got around to measuring the 55mm PMC dome.
I ran the sweet from 100hz-20khz near field. Picture of the setup is attached. Nearfield measurement
That dip from 850 to 1200 might be a little annoying.
No matter what I did there is a dead spot at 6500hz. Straight up dead. Almost like they built a notch filter into the unit somewhere in there. Kind of crazy. I even took a measurement from 6000-7000 just to be sure. Yup, dead spot. Strange
This response is not really what I expected. Now onto the REALLY crazy part. What you've all been waiting for....... the distortion.
You can interpret this graph however you want but I'm seeing no reason why you could use this from 250hz right on up to 5khz. This is a straight up mid range. Not an upper mid range. A full range mid range in a 55mm dome format.
Check out the distortion between 1k and 2k. Crazy low. I think this is why I like the sound of it so much. To me, that 1000-2500hz range is the most annoying place to have distortion. A lot of speakers I don't like because they cross cones right above that range. They let the cone mid play that while the cone of the mid is already starting to break up. This just sounds bad to my ears.
Are they worth the $380 I paid for the matched pair? To me, 100%.
I ran the sweet from 100hz-20khz near field. Picture of the setup is attached. Nearfield measurement
That dip from 850 to 1200 might be a little annoying.
No matter what I did there is a dead spot at 6500hz. Straight up dead. Almost like they built a notch filter into the unit somewhere in there. Kind of crazy. I even took a measurement from 6000-7000 just to be sure. Yup, dead spot. Strange
This response is not really what I expected. Now onto the REALLY crazy part. What you've all been waiting for....... the distortion.
You can interpret this graph however you want but I'm seeing no reason why you could use this from 250hz right on up to 5khz. This is a straight up mid range. Not an upper mid range. A full range mid range in a 55mm dome format.
Check out the distortion between 1k and 2k. Crazy low. I think this is why I like the sound of it so much. To me, that 1000-2500hz range is the most annoying place to have distortion. A lot of speakers I don't like because they cross cones right above that range. They let the cone mid play that while the cone of the mid is already starting to break up. This just sounds bad to my ears.
Are they worth the $380 I paid for the matched pair? To me, 100%.
Attachments
Maybe a nearfield cancellation effect. Try a slightly different distance, that may also change the 850-1200 dip.
Why nearfield? I only take nearfield of woofers because I can't get reflection free measurements below 250-300Hz. If you put the driver on a pillow on the floor and measure 1m directly above it, you will get a reasonable infinite baffle measurement.
Your mic is beyond "near field", it is within the horn/waveguide.
Interior boundary reflections from the horn walls could account for the cancellation null ~6500.
At any rate, if you want a representation of the mid dome waveguide's response, it should be measured in the far field, as the last two posts suggest.
If the driver's SPL level was 105dB at ~5mm, SPL at 1 meter would only be ~57dB.
Distortion of a fraction of 1% at such a low SPL could be expected from almost any driver.
Looking forward to seeing some far field measurements.
Last edited:
I didn't have time today to flush mount it inside of a board and take all the far field measurements. I do what I can
Yup, I definitely did mess that up lol. I should have remembered this after I did all that waveguide research on the planar mid this winter. This is what I get for trying to take a measurement quickly between meetings.
Eventually I will get it flush mounted in a board and try to take axial measurements. My summers are pretty busy so it might have to wait a little while
Last edited: