DIY LCR questions

[BDixon]

There is so much info here it's crazy.

I've been toying with the idea of changing my Tumult sub to a PR setup but honestly I really like it and most likely will end up going with an LT circuit and bigger amp. Anyway, onto my questions.

I've always wanted to build some mains and a center. The woodworking isn't the issue, it's all the info.

For one thing they'll be in my living room so there will be a TV between the L&R. The CC will have to set in font of or below the TV. My current L&R speakers(M&K S-125's) are about 21 inches from the wall(measuered to the front baffle) with about 6" between them and the side of the TV. The TV is pushed back as far as I can so the speakers actually stick in front of the TV about 6". The center sits on the same shelf as the TV and simply sets in front of it. I sit about 7.5' from the CC. The room is 12' x 15' and is open to a small dining area behind the sofa.

I see talk about needing the speakers out in the room, or more room behind them than between them and you etc. Also, the crossover talk is beyond me at this point but it's clear some of the crossovers are designed for the speakers to be setup a certain way in the rooms.

Am I worrying to much? For a first shot at this should I go with something like the NatalieP or the Modula MT? Honestly I really like the looks of the --
Dayton RS WMTW Center & TMWW Mains
or
Dayton RS 3-way towers(not sure what to do for a center here though) and I think I saw something about them costing about 1K each, which is more than I'd like to spend. Also since I've alreeady got a Tumult subwoofer this setup is probably way overkill in our little room.

Thanks for any thoughts,
Brad

[wrz0170]

Build them and they will come

Hi Brad!

Welcome to speaker madness. I am a lot like you. Woodworking is not really an issue. It was trying to mine through all the good information in here and figure out what I wanted to do.

Crossovers: To be honest, I leave the actual understanding to the Gurus who design them ;x( It really is an art and science it itself. Heck, I barely understand how to look at a SPL response and interepet all the pretty colors and lines.

However, with that said above, building the actual crossover isn't that bad or complicated. It's basically connecting the dots. Get a good 40w soldering iron. I bought a Rat Shack station model with the sponge, etc. $21. It's the one with the smaller tip. Those fat tipped ones didn't work too well. Get some .8mm WBT solder or Wonder solder. I found 3ft strands of WBT for $2.25 a piece on Ebay and got 30ft and an extra 9ft bonus for bying 10 strands. Buy a roll of 16g wire. You can use better if you choose. Grab your schematic and do a dry lay out on some paper. Then, it's a matter of getting them on a 1/4" board and hot gluing the parts and then soldering the lines. If you look on the stickys, most of the time, the good folks here do much of the legwork for you as far as figuring out the crossover components. Sometimes you can find a parts list and it's a matter of going shopping with list in hand.

I really don't think you can go wrong with the RS WTMW center (next project for me) and the RS TMWW mains (next one after that for me). The BOM for the mains can be found I think on the last page. If you want, just PM me and I would be happy to send you the schematic, BOM and cabinet layout for the mains.

Hope this helps a little

William

[BobEllis]

Building a proven design is a good way to get your feet wet in this hobby/obsession. You picked up on some of the key design considerations. One advantage of a DIY design is you can make it work for your exact situation.

Your speaker to rear wall distance is good for the designs you'll find here, but you ought to try to get a bit more space between the speakers and TV for better performance. As close as you are, the TV acts as an extension of the baffle, causing the system to have too much baffle step compensation (they will be bottom heavy)

For the center, use one of the low/no baffle step crossover designs, for the same reason. Most of the designs you find here have baffle step compensation built into the filter in such a way that you can't just change a part or two to suit your requirements.

Personally, I don't see a need for expensive solder in speakers (or the electronics I build to drive them. No disrespect to those who use it, I'd rather use the money on some film and foil caps in the tweeter circuit (Jon's favorite tweak) or something interesting to hear/watch instead.

[cjd]

The RS 3-ways run ~$1k for the pair. I could probably work up a reasonable center from the data I have, but I don't think these are right for your situation anyhow - my cabinets are deeper than the space from baffle to wall in your current setup.

The "other" 3-way RS series here (which started with the center) is a better match, but it may still be ab it much if you need to keep your spacing and such where you have it. Excellent option if it'll fit well.

Next step down in a 3-way probably does not exist here. Yet. I have other furniture to build before I get to redoing my HT. However, the Modula series (with which I would include the Natalie P's) may be a good option for a 2-way. I have a smaller MTM as well based on the RS150.

The advantage of smaller speakers is you'll be able to give them more room to breathe. But you'll get better performance (IMHO) out of a 3-way.

C

[BDixon]

Thanks guys.
I didn't mean to imply I wanted to roll my own design. I don't know alot but I know I'd be in well over my head lol. There's just so much info that I really wasn't sure what designs would do a better job in our room.

So spacing the speakers away from the TV is suggested. About how far?

Here's a pic of the room I'm working with.



If needed I can always build a new stand for the TV. It won't add that much to the cost when building an LCR setup.

We had the TV on the left wall(going by the picture) before but that meant the surrounds were mounted directly above us with a wall right behind the couch. I really didn't care for it. This setup has the surrounds to the side of us and it's also opened up(dining area) behind us. Seems to sound much better to my ears, especially for movies.

Thanks,
Brad

[BobEllis]

You've got plenty of room to the sides. Move the speakers a couple feet out from the TV and you can use any of the standard designs - Modula MTM, NatP, etc. You should find your current speakers sound better out a bit, too.

While I agree with Chris that better performance can be had with a three way, you'll get good performance out of any of these designs. Using parts from PE and Zalytron NatPs ought to run around $375 or so.

RS180 based designs could be build into a tower configuration - keep the baffle width the same and either partition the tower to the correct volume or try a MLTL as discussed in the NatP thread for "leave the sub off except for movies" extension.

[cjd]

In that space, I would do:

Natalie P's or Modula MTM's across the front, Modula MT's in the back. Tower mains.

My RS150 based MTM's (a TM for surrounds would be no trouble to work up as I think I have it mostly done already).

The 3-way RS projects already published here are going to be big and IMHO will be oversized in that room. Mine would dwarf your couch. Some time in the future I *am* going to be doing some 3-ways with the RS180 as the woofer(s) (I am 99% sure on this still) which would probably be a more suitable for the size of your space.

Try moving your current speakers out so the right one is snug against the armrest (but to the left of the couch, just barely) and the left one is moved over to balance that out. See what that does for you.

C

[BDixon]

I moved them away from the TV this afternoon. It does change the way they sound. I didn't think it would make that much difference actually.

You guys are probably right, the big 3-ways are most likely to big and overkill for my room. I've just always liked the look of the bigger floor standing towers.

Thanks,
Brad

[Brian Bunge]

Chris,

Seeing as I will have a table saw set up again soon, I'd like to see a TM version with the RS28A and the 150! (nudge, nudge; hint, hint)

[BobEllis]

There's no such thing as overkill in my book - in a 14 x 22 room open to the dining area I have a pair of 18" subs in 8 cubic foot cabinets. The only thing keeping me from going with towers is that I use the subs as stands for my mains. I plan to run them up to 2-300Hz once I get my active XO breadboard put together.