HT Project: New in-walls + surrounds

[---k---]

Progress! Good for you! You going to have any time in the near future for my center project?

[cjd]

Of course... er... yeah. um. loads of time.

I have to make time, otherwise I get lost in idle time-wasters and lose it. So, yes. In fact, if I have all my stuff out and hooked up again for doing measurements it's kinda easier to just add another project.

C

[dlneubec]

If you post an impedance curve, we could probably see if they are in fact the RS90. The RS90 had almost no inductive impedance rise. Very low distortion too.

Hi John,

Here is what I got when I took some very, very rough measurements. The driver was in a cardboard box when this was taken. Does that look like the RS90 Z?

[---k---]

Of course... er... yeah. um. loads of time.

I have to make time, otherwise I get lost in idle time-wasters and lose it. So, yes. In fact, if I have all my stuff out and hooked up again for doing measurements it's kinda easier to just add another project.

C

I know you're not going to be willing to let your measurement gear take over your basement for very long. If you give me a date of when you're going to have your it up and running, that might inspire me to get out into the garage and put a box together.

Though, with the TV above, I wonder how close I'll be to inwall... Maybe after you get your measurements, I'll have to see if I can get some taken in my room. I think I got everything needed.

[jkrutke]

Hi John,

Here is what I got when I took some very, very rough mesurements. The driver was in a cardboard box when this was taken. Does that look like the RS90 Z?

Yup, that's the RS90 or at least a version similar to it. There is copper in the motor. The regular B3S/N has a much more rounded impedance, and at 20 kHz it's around 28-30 ohms. PE likely chose not to carry the RS90 due to poor low end performance with high Qts. The copper sleeve required a bigger gap, lowering BL and all the effects that go with it. Great midrange though as long as it wasn't pushed below 150Hz or so.

[cjd]

Pity about the RS90. Superb looking driver.

My remaining quandary is RS180 vs RS225. And if 225, should I be going with 2 RS150's. Obviously, F3 is lower by about 10Hz with the 225 (70 vs 60Hz). I have an IB sub that is mounted center of the front wall. So I'm pretty sure the 180 will do everything I need, and then some - smaller box size will be a boon.

The other quandary is whether to go TM with RS180 or RS150 for surrounds. Or if I should be pondering something else entirely - in my HT they have to be mounted overhead. Maybe a bottom-mounted woofer and side mounted tweeter for side surround, more basic TM for rear surround.

So many possibilities.

C

[Hdale85]

Yeah Ruben doesn't sell the screen material anymore...kind of ticks me off because thats how he started out and now he's selling his screens for a crazy amount of money and not catering to the DIY members that formed his little company. Oh well I guess. The curved 92" screen is like 2200 dollars shipped just seems like way to much money.

[mmoeller]

Yeah Ruben doesn't sell the screen material anymore...kind of ticks me off because thats how he started out and now he's selling his screens for a crazy amount of money and not catering to the DIY members that formed his little company. Oh well I guess. The curved 92" screen is like 2200 dollars shipped just seems like way to much money.

Try and find one cheeper. I think you might have a hard time.

[Hdale85]

Well I don't want to purchase one is the point I want to build one. And I can build one for way less then that. And the point really was that he started out with DIY community and doesn't cater to it anymore which kind of sucks.

[cjd]

Check out Seymore AV. Seriously. I should have my screen whenever FedEx delivers it (their tracking system doesn't know its head from its tail). ~$200 for material to cover my 41" tall 96.5" wide 2.35:1 screen at a 12 degree angle. Response has been exemplary from the company (or rather, from Chris over there...) - very similar (not quite exactly the same I guess, but damn close) as SMX. I'll be designing these speakers for use behind this so will have measurements with the screen in place - I'll also do measurements without the screen, as I believe the design I'm doing will work as a more general in-wall concept for people desiring such.

C

[Brian Bunge]

Chris, sorry if I missed this, but are you doing a WTMW vertical arrangement for the in walls?

[cjd]

Yes. WTMW or WMTW - these're probably going to have the tweeter a bit above listening axis regardless - putting tweeter under mid will lower the T but also tilt lobing slightly also.

Though I believe a horizontal alignment would be reasonable also. Crossover is low enough on the W's it should avoid comb issues (and that's something I could not say as surely were I going RS52)

C

[cjd]

Parts ordered. Now to wait for them to show up and probably knock some boxes together. Plus some wall surgery, of course.

Dayton RS180-4 - for mains, 2 will be used, wired in series. For surround, a single will be used.
Dayton RS150S-8 - for mains, 1 will be used as a midrange
Seas 27TDFC - for all, 1 will be used. Chosen for its rising response on the top end which will help behind the screen as well as the probable off-axis listening on surround channels.

I pondered at length whether to use the RS28A (would have cost me less than $28 more for 7 channels worth with current sale pricing) but in the end, the rising response of the Seas won the day compared to the drooping response on the RS28A. I believe it will work better this way all around.

C

[cjd]

So I guess the first thing is going to be an updated IB sub!

Currently a pair of Dayton 15" IB subs driven by the PE 2400W plate amp. This can cause the wall to flex (the back wall, the sub is manifold mounted on the front wall) so of course, it's not sufficient.

Enter 4 Tempest-X (double XMAX per driver, twice as many drivers... ) and 1800W of power (bridged into 4ohm). :B

We'll see when it gets here.

I have to hurry up and finish my H@lf too!

Other drivers for mains/surrounds should be here over the next few days.

C

[ThomasW]

So I guess the first thing is going to be an updated IB sub!

Add to that a good pair of headphones and you're ready to go.... :B

[dlneubec]

So I guess the first thing is going to be an updated IB sub!

Currently a pair of Dayton 15" IB subs driven by the PE 2400W plate amp. This can cause the wall to flex (the back wall, the sub is manifold mounted on the front wall) so of course, it's not sufficient.

Enter 4 Tempest-X (double XMAX per driver, twice as many drivers... ) and 1800W of power (bridged into 4ohm). :B

We'll see when it gets here.

I have to hurry up and finish my H@lf too!

Other drivers for mains/surrounds should be here over the next few days.

C

Wouldn't it have been easier to buy 6-12 of those PE DOTD Aura Pro Bass Shakers and add them to your seats, walls, etc. at $25each? :W

[cjd]

Bass shakers don't cut it. Nowhere near the same. Maybe if I wired 'em up like I was on one of those hospital machines... I mean, maybe if I wired up charges, but they can only blow the room to bits once...

Actually I have to partially rebuild the wall first to work with the in-walls as I'm planning them. Then pull the current screen off the frame, move the brace from the center to two, install the new AT screen material. Then build the new boxes, install, measure, design crossovers... And all the while, I need the HT to be usable.

New receiver will be required, new projector (1080p) and HD source. I'm doing this in the order of things least likely to have drastic changes in price first, with the projector and source last on that list.

C

[cjd]

I'd better salt my walkway tonight! 200 pounds of equipment to be delivered tomorrow! Those poor shipping folks get hammered with all sorts of unreasonable work like this every year... this should be the last of what I need for this phase, except for the H@lf parts I do not yet have.

Weather has prevented me from acquiring plywood yet. Maybe the weather will be clear this weekend. I can hope.

I had some vague hope of getting this done before the holidays but... I don't think that's realistic.

C

[Brian Bunge]

So you are going to build the back boxes for the front 3 from BB as well? I don' know why I was thinking MDF.

BTW, have you played with any midbass drivers that you like more than the RS150? Or does anything peak your interest?

[cjd]

I don't work with MDF at all if I can help it. I might use the cheap 13 ply though.

Midbass drivers, I don't play much you know? This is more about working with drivers I know I like, are priced well, etc. I'd love to mess with some of the 4" T-B drivers, some of the Peerless line. Heck, I'd love to mess with some of the Scans. Not to mention pro stuff. And the Neos. And... realistically, I only have so much room in my house. And other projects, many in various states of incomplete-ness.

C

[---k---]

What are H@lf parts?

You're going to be a little disappointed in my center box. I used some cheep ply for it. And, if I don't get my butt in gear, it isn't going to be nearly as well braced as my previous attempts. Ahhhh, it will be fine. Everything else is overkill.

[cjd]

The H@lf is a project Thomas and chasw98 have worked up for sub integration. Nifty little box. I have a PCB, need the various resistors and transistors and such. They're on the way. Among other things it will output balanced signal, which'll be good. Wish it had a shelving function built in.

I should have 150lbs of foundation-shaking house-destruction sitting on my doorstep at the moment. Er... I mean, well... I hope it's there still when I get home! I might try tossing two into my existing manifold if the bolt holes line up. But I think tonight is movie night, so probably not. Will get ply to build the new manifold this weekend, and hopefully the front wall boxes too. Maybe the surround boxes. Well, at least the parts cut. I doubt I'll get it all assembled this weekend. That's a lot of work! Plus I have to mount the AT screen to my frame when it won't mean we have to skip a movie night.

C

[---k---]

H@lf - Ohhh. Didn't realize that is had progressed to the point where it had a name.

Edit: Just found Thomas's page on the H@lf. Those PCBs look nice! I wouldn't mind getting my hands on one.

http://home.comcast.net/~thomasw-2/Chasw98HALF-SUBproject.html

[---k---]

I should have 150lbs of foundation-shaking house-destruction sitting on my doorstep at the moment.

Is that the 2-pack or 4-pack?

[cjd]

um... it's a two pack. of, uh, two. Yeah.

Uh oh. I hear big truck and bangs just now! Probly just a snow plow though.

[Hdale85]

Hmm... so does that H@lf box convert single ended to balanced output as well? Or is it just RCA in XLR out?

[cjd]

I need to get some pictures going!

The wall is mostly re-framed. I have to put the vertical supports in for the speakers, but the "window" framing for it is in. Because I have access to the back I left the drywall hung and trimmed down studs, capped, installed new... Cramped space for the work though.

The new IB is installed. Man it's big. And heavy! Looks good though - I did a better job on this manifold. 1.5" birch ply (cabinet grade). I even gave the backside the 3/4" roundover treatment, since it's in a "crawl" space and I do have to walk back there now and again (the main water shutoff valve is behind it). I've not got the Face amp installed yet, but to allow movie nights I've wired up one VC on two of the 4 drivers and plugged 'em into the old 240W amp.

This weekend I should finish the framing and install a more official (and secure) way of hanging the screen. It fell the other day, put a hole through the screen off to one side (fortunately, I've not installed the new AT fabric yet so this screen material is already slated for removal!) It also dinged the velvet wrap, but I think it's minor enough I'll be able to live with it.

I don't know if I'll find time to put together boxes for the main speakers this weekend. I'd sure like to, but at most I could get the parts cut - need to focus on cleaning everything up so it's company-ready for the holidays, and having boxes out being glued together probably doesn't count as "clean" - plus I have a shelving unit partially completed that is to go in the HT as well, and those parts are in the family room right now...

the H@lf can convert single ended input to true balanced output. Though the chip on the parts list I got is the surface-mount version - not sure how that gets wired up to this PCB!

C

[ThomasW]

No pics = no project....

the H@lf can convert single ended input to true balanced output. Though the chip on the parts list I got is the surface-mount version - not sure how that gets wired up to this PCB!

That's a mistake, fire off a PM to Chasw98 about this since he created the list.

[---k---]

Sounds like I might get put to work on Saturday??

[ThomasW]

Chris,

I just checked Chas' H@LF project file. The op-amp package in the parts list is PDIP-8. If you received surface mount devices problem is with who ever pulled your order at Mouser. Give them a call..

[cjd]

oops!

Well, I was going to see if I could just solder in pin extensions but maybe I'll give them a ring. I'll verify what was ordered, what was on the packing slip. I've hand-soldered these little guys in the past. Fun stuff. I hadn't gotten to checking that - time is always short, but the holidays make it moreso (and we're hosting this year so it's even *more* short)

edit: Thomas: I just checked and it's definitely the SOIC not the PDIP in the parts list. 1646S08-U is the SOIC 8, 1646P08-U is the DIP 8. Did I look at the wrong project file?

C

[ThomasW]

Replied via PM

[cjd]

Screen properly mounted to the wall now! Not going anywhere. Easy to remove, so I can stretch the new screen any time. So now to build boxes, assemble, and get to speaker designing!

Subs sound superb, even with just one coil working on a pair.

C

[Ale]

While not an in-wall specific question, why WMTW vs. MTM for the LR speakers (I understand for the center). I've been reading posts here for quite some time and I see a pattern of many who have built MTMs and in very short order move to some sort of 3 way. I would prefer to build something that I would can enjoy and not regret (and hopefully avoid upgrade-itis for several years (at least).

So, what would I gain sound wise from 3-way vs 2-way for HT (mainly) LR speakers?

[ThomasW]

Ale,

We typically see people starting off with a very low budget and opting for a low cost small driver MTM or MT. Then they realize they want/need more output so it's upgrade time.

The other scenario is they find out how good a DIY design can sound and want more..

[chasw98]

edit: Thomas: I just checked and it's definitely the SOIC not the PDIP in the parts list. 1646S08-U is the SOIC 8, 1646P08-U is the DIP 8. Did I look at the wrong project file?

C

I have changed the BOM at Mouser. Chris, did you get the package I sent you?

Chuck

[cjd]

Yup. I have to straighten all the pins though, it got squished pretty bad. Holidays aren't a good time to disappear into the black hole I call my basement workshop.

A 3-way tends to be twice (or more) the cost in crossover, plus added driver cost. However, IMHO it produces cleaner midrange since the mid isn't being asked to also handle bass, where excursion comes into play.

The real question people will have is why RS150 for mid.

C

[---k---]

The real question people will have is why RS150 for mid.

C

Yeah, I'm still asking myself that.

Nah, I like mine. I think the RS150 is a slightly maligned driver. The bigger question is that SEAS tweeter over the RS28a.

[Ale]

The real question people will have is why RS150 for mid.

C

That is kind of my question. Not so much the driver it's self, but how do you select the type/size of the 3-way. For example, is it better to take the midrange off the RS-180 by adding a mid or take the low off a say an RS-150 MTM by adding woofer(s).

I do want to build a 3-way for LRC. I fully understand the additional costs and complexity of the crossover. I guess I'm trying to select the proper 3-way for me.

I do have a sub I built a few years back. Sorry, it's small by HTGuide standards (AV-12 PR'd sub). My current electronics only allow a higher crossover point than I would like. So, if I want a 60-70 Hz crossover point would sealed be the best option? If sealed, should I could build towers or build another sub to use as a stands? I will build my own cabinets.

The D.A. Khanspires look really nice but a tad large for the room and probably my sub would not keep up. So, back to my original ramblings, where's the sweet spot? Jed's maxxL16 look really nice but they are over double the driver cost of the neoD CC. I also, have poor placement options for the rear speakers so could not build the same speakers for the rear. I would need something like a TM for that. But what would integrate well with the either the maxxL16 or neoD CC? I see many of the same design choices being discussed in this thread that's why I started here. While I have no exact budget, I would like to do this as smartly as possible.

For reference, my room is approximately 13'x24'. I still have a big ol' glass tube on the 13' wall. The back of the room is open to other rooms. I sit about 10' from the front of the TV.

BTW, thanks for the responses!

Al

[Jed]

But what would integrate well with the either the maxxL16 or neoD CC? . . .
Al

The Lineup D4 works great as a surround.

With enough convincing I'll work on a MaxxL16 WWMT to match the MaxxL16CC. That should cut the costs down a lot and sound just about as good as the MaxxL16 WWMTM.

Edit: For more info post over in the Lineup threads....

Jed

[cjd]

Of course, I must answer questions I ask.

I started out with a few knowns here:

* A vague budget
* in-wall with no real box depth limitations - they're 7" internal depth, 12" wide internally, and 34.5" tall.
* Placement behind an acoustically transparent screen
* Seas 27TDFC has a rising response that lends itself to use behind a screen and is known to integrate well with a very broad range of midranges
* RS180 is tough to beat for SQ on the low end, displacement, etc. I could have gone with a single RS225 or RS270 but I wanted to manage vertical lobing a little more carefully.
* Integration across a family of drivers is easier than if I introduced a new mid - I could have gone Seas Excel but wanted to stay away from introducing something like the Peerless

For the mid the question became, dome mid or cone mid. I wanted to run a shallower slope and the mid far deeper than a dome would allow, so that meant cone. Which led me to the RS150. This also means I could use either RS180 or RS150 based 2-way designs for surround and maintain near perfect voice-matching. Doubly good.

Because these are in-wall they're not really going to be suitable for others - however, Ryan's center may become an interesting option for folks wanting to downsize a little from the Khanspires.

C

[Hdale85]

Because these are in-wall they're not really going to be suitable for others

Who says we dont' have people lurking here looking to put inwalls into their theater? If I were building a theater good chance its the way I would go.

[cjd]

I should have said, they're not going to be *as* suitable for others. They'll be absolutely perfect for some folks - crossing 60-70Hz to a sub should be no problem, good power handling, ideal for AT screen use 'cause I'll be measuring with the screen in place...

[cjd]

Big holes in wall cut. Boxes trial-fit. This is going to work! I think...

More family over this weekend so I have to have everything clean and shiny again, so yet more waiting.

C

[chasw98]

What? No pictures!