Suggestions for front LCR's

**Bear** · 09 August 2020, 13:20 Sunday

A quick response based upon what you are showing: try to go with an in-wall design. Don't build discrete speakers than then shove them into a small cave. If you put a normal speaker cabinet inside your existing cabinetry, then that will be about the worst case for sound reproduction (lots of constructive and destructive interference).

If you are going with DIYSG and Marty style gear, then that says you really care about SPL and movie effects most of all. I don't have an opinion on the DIYSG stuff in general beyond noting that it tends towards big SPL as an important design criteria. With a decent subwoofer and high-ish crossover, something like the in-wall Zaph 5.2 design series (from Madisound) should be "good enough" for most small to medium sized rooms (and fit within your budget given the need for additional cabinet work and shipping). If you are sitting 5m away from your speakers, and you want 105dB at your listening position, then those designs aren't for you.

I believe that there were some NatP in-walls, but I don't remember off the top of my head whether those exist or not. The NatP would arguably be a next-level design vs the ones from Zaph (certainly more SPL, depending upon XO to a subwoofer). I'm also not sure that all of the parts are available from the NatP design. If so, then it would be an easy recommendation. There are rumblings of a replacement, but I doubt that any such design would be ready by your first targeted movie night.

**Bazfletch3** · 09 August 2020, 21:23 Sunday

Thanks Bear

Of course you're reinforcing what I already knew (but was trying to ignore...) - you always pay more attention when someone else says it in my experience! The cabinetry is going to pose huge problems. What I do find interesting though - and confusing - is that when trawling through many of the high end dedicated theatre builds, that many of the front baffle walls (either around a screen or behind an AT screen) would appear to me to be beholden to very similar issues to those that Im facing... speakers simply sitting on top of one another in stacks against the wall, or within a framing structure of sorts - usually with plenty of damping material around them of course. I guess thats what possibly led me towards the Marty/DIY 88-Special combo as a solution, as the dimensions are such that I could effectively build those in to the cabinets, and have them take up the entire area (if not necessarily volume), which I guess effectively makes them "on-walls"?... (or a combo in/on-wall?..) and not just "in a cave"...

That and the fact that Ive always spent more time on AVS forum - and the flavour of discussions there is very much geared around reference level performance.

Im actually not at all wedded to the idea of high SPL's - and in all honesty things will probably only get cranked up a couple of times a year, so Im open to any suggestions - or more importantly, options with compromises - as Im kind of looking for the "least worst" option, rather than the "best" in this case.....

Ive certainly been looking at the NatP's (and various Modula's), as well as the KhanCentre and in-Khan-Neatos. Another that caught my eye was the HT mains that are shown on DiVine Audio webpage (which look to be TMWW)- but then I cant find any additional info on them other than the crossover detail; no mention of cabinets or what design they are a variation of.

And Ive also been looking at the Zaph 5.2 family, which look very interesting.

If it comes down to it then Im more than happy to buy in from overseas (which would be the case with the Zaph designs), whereas the NatP's, Modula's and Khan's appear to be constructed using parts I can buy locally (save for the components that are no longer made...)

More trawling and reading....my head hurts!

Baz

**Bear** · 10 August 2020, 09:21 Monday

Originally posted by Bazfletch3

Of course you're reinforcing what I already knew (but was trying to ignore...) - you always pay more attention when someone else says it in my experience! The cabinetry is going to pose huge problems. What I do find interesting though - and confusing - is that when trawling through many of the high end dedicated theatre builds, that many of the front baffle walls (either around a screen or behind an AT screen) would appear to me to be beholden to very similar issues to those that Im facing... speakers simply sitting on top of one another in stacks against the wall, or within a framing structure of sorts - usually with plenty of damping material around them of course. I guess thats what possibly led me towards the Marty/DIY 88-Special combo as a solution, as the dimensions are such that I could effectively build those in to the cabinets, and have them take up the entire area (if not necessarily volume), which I guess effectively makes them "on-walls"?... (or a combo in/on-wall?..) and not just "in a cave"...

A small-ish driver grouping on a large-ish baffle will give you most of the performance of a true infinite baffle. This is also easy to see for yourself. If you are and Excel user, then Jeff Bagby's Baffle Diffraction Simulator is really easy to use and understand. If you want a dedicated program that's a bit more powerful, but arcane, there's the Edge simulator program (plus a bunch of others). A 500mm wide cabinet will have baffle step up to about 700Hz (main effect in the ~350Hz range). If you can give at least 100mm of spacing between any edge, then the rest of the diffraction effects start to drop off. Since you're in Oz, grab a bit of the Strategic Wool Reserve and add a layer of proper wool felt on the front of the baffle (see some of JonMarsh's threads). That will help a lot as well, and all of that can be hidden behind your grill cloth. You can have the subwoofer built into the cabinet. Oh, yeah, you might want to simplify your subwoofer build down to a pair 10" or 12" subs (depending upon volume and baffle area). The Marty thing may be overkill (I was once told, "can't we turn the subwoofers off?").

That and the fact that Ive always spent more time on AVS forum - and the flavour of discussions there is very much geared around reference level performance.

I spent a ton of time over there in prior lives. I'm familiar.

Im actually not at all wedded to the idea of high SPL's - and in all honesty things will probably only get cranked up a couple of times a year, so Im open to any suggestions - or more importantly, options with compromises - as Im kind of looking for the "least worst" option, rather than the "best" in this case.....

Look at some of the Dayton RSS series or the CSS SDX10/12. In general, more smaller subwoofers are a LOT better than a single big one.

Ive certainly been looking at the NatP's (and various Modula's), as well as the KhanCentre and in-Khan-Neatos. Another that caught my eye was the HT mains that are shown on DiVine Audio webpage (which look to be TMWW)- but then I cant find any additional info on them other than the crossover detail; no mention of cabinets or what design they are a variation of.

And Ive also been looking at the Zaph 5.2 family, which look very interesting.

If it comes down to it then Im more than happy to buy in from overseas (which would be the case with the Zaph designs), whereas the NatP's, Modula's and Khan's appear to be constructed using parts I can buy locally (save for the components that are no longer made...)

More trawling and reading....my head hurts!

Baz

At some point, remember that the longer you are researching, the less you are enjoying the system. ALL speakers have inherent compromises before they ever land in a room. Focus on "good enough". For most people in most rooms, where HT is their realistic bias, having small-ish MTMs for left and right and TMs for the surrounds is Good Enough. Competent versions of these will play loudly enough to do damage with a crossover to a sub in the 100Hz - 120Hz range. The center channel is where the sideways MTM doesn't make sense if you can get away with either a TM or a WTMW. Yes, a single TM is better than a MTM for center channel purposes (smoother horizontal dispersion), but most designs don't have the form factor to fit. The Khan series starts from a better base on this, but driver availability is an issue there, I believe, but your cabinetry should lend itself to a vertical TM arrangement for a center channel. A single 7" (17cm/18cm) driver in a sealed cabinet can often do 110dB down to around 120Hz - 140Hz. If you sit 3m away, then subtract 10dB.

"Reference" is 85dB with +20dB of overhead. If you go with that same 3m seating distance, then you need a speaker than can produce 115dB at 1m. That's ridiculously loud. I find something down in the 75dB range is fairly loud in an otherwise quiet room. I'm targeting 105dB as a design standard these days. That's still aggressive for many designs, but it's can be achievable as a short-term spike for several designs with a high-ish crossover to a sub.

**Bazfletch3** · 11 August 2020, 07:44 Tuesday

Thanks Bear, brilliant advice.

I had almost purposefully avoided diving into real technical detail too much; I know my personality, which is typically to try and understand and quantify every little detail (i come from an engineering background....enough said) and I know in this instance I just dont have the time for that rabbit hole - which I would undoubtedly jump into anyway! But I will try to do a "shallow dive"

Its a little frustrating that so many of the archived designs now have component availability issues, with many of the original designers having moved on, so I think I would be better placed to just focus on some of the more current MTM builds. I'll try to throw together a modified design of sorts and get it out to the forums for some educated people like yourself to pick apart!

Cheers

Baz

Suggestions for front LCR's

Suggestions for front LCR's

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