Modula MT & Hypex plate amp

[jquin]

Hi All
Ages since I was doing speaker DIY but a requirement for a new sound system was created when I purchased an intel NUC for a HTPC.
What with the only speakers being those in the TV I saw the need to improve on this situation.

I had a left over Modula MT minus the xover and decided to check out class D amps and bi-amp/active xover the thing as a mono monitor.
In my search I found out that there are a few companies offering plate amps with digital filters for just such a situation.

I'm going to buy a hypex AS2.1 plate amp and report back on how well it goes.
I will be interesting to see how well I am emulate the filter requirements with their software.

I'm not trying to push hypex products here but if mod think this post is too commercial then feel free to swing the axe.

[---k---]

Jeff B. did RS180 w/ RS28 MTM design using a 70W plate amp and a few passive crossover components. He posted really really liking the results. His design might give you some inspiration. He's posted the design somewhere at PE Tech Talk. I don't remember the name right now.

[jquin]

I've taken delivery of the plate amp. It looks like an ideal product for two way DIY.

I'll post pix and results soon

[Hdale85]

Are those the plate amps with the DSP built in? If so you could technically use any drivers you want as you could do the crossover work actively via the DSP.

[JonMarsh]

Will be interested to see how that works out for you! The Modula MT crossover as it currently exists would not be trivial to implement in DSP- I did a study of that for our company back when we were making and selling Class D amplifier chips with built in FIIR filters.

[5th element]

It's a lot easier to do with IIR filters though.

[jquin]

They use iir filters with 12 biquads available per driver. You can use an all pass to correct for phase using a FIR.

[jquin]

I just has a quick bash today at the eq/xover.
It sounds like crap at the moment but I'm blaming the RS28A. I might be crossing it a bit low but I loathe metal tweeters. I might throw my ss6600 in and have a listen

[jquin]

Again at the risk of spruiking a vendor let me say that the after sales support from hypex has been excellent.

[JonMarsh]

Be careful about blaming your RS28a... that's a very good metal tweeter, and does not have the sonic faults of most- and I would rate it a better bang for the buck than the 6600, having used both.

What you MUST do with the RS180, though, is deal effectively with it's upper break up modes, as I do in the Modula MT and the NatalieP, using elliptic filters. With a more conventional crossover approach, there will be a lot of output from the RS180 in the tweeter range, and believe me, you won't like it! :W I've run into a lot of people working with the RS180 in the old days that overlooked the HF hash from the woofer in their crossover design. Suggest you measure the RS180 with your DSP crossover filter by itself.

Model the Modula MT crossover for the woofer and try replicating that with your DSP electronics. That's probably going to put you in the best shape for then working on the tweeter section.

[jquin]

Oh when I blame the RS28 what I mean is that to date I haven't liked my experience with metal tweeters.
I have a built Modula MT which has the discrete analogue xover you designed running a RS28 but I have changed it over to the 6600. I like the 6600 better.
Now all that isn't to say that I haven't screwed something up or not tweaked it enough.

Additionally I tend to be more annoyed with metal drivers when I'm listening to crappy sources.
Something from chesky records sounds fine on all drivers but silk tweeters seem to do a better job at hiding the artifacts in mp3s and the like IMHO.

Seeing as how it will cost me $100 is dollars to get a RS28F I think I'll be persisting with the 28A this time for longer.

I still have no idea whether cascading multiple second order IIR filters will be able suppress the brake up modes sufficiently.
At the moment I'm still in the set to work stage.

I'll look forward to eating my words, hopefully.
Thanks for the advice

[jquin]

BTW does anyone have impulse response measurements for the RS180 and/or RS28A.

The hypex design software can make use of these and I haven't had the chance to measure mine yet.

Any help would be appreciated.