Subwoofer wiring issues...

[aceinc]

Sorry for the long post, but I wanted to put in enough info to make what I was doing somewhat clear.

I have a Yamaha HTR-5860 that I will be putting into a 26'x15.5'x9' room with a 3'x6' fireplace protruding into the room midway along one of the long walls, and a bay window in the middle of one of the short walls. The TV is on the opposite short wall from the Bay window. I have installed in wall 12 guage wire from the TV location to near the four corners of the room, two sets in each of the bay window wall outlets.

Due to a spousal edict this newly remodeled room WILL NOT be full of speakers. I have built a pair of North Creek Echo's and have the materials to build three more. This leaves the subwoofer(s). My wife & I agreed that I could have subwoofers, if they were disguised. To that end we bought a set of three trunks, the largest one can house up to about a 3 Cubic Feet internal volume sub which I intend to put a Rythmik Audio Direct Servo 12" or 15" kit. The smaller trunks will net out at about .68 cubic feet, and I intend to put in either a Dayton Titanic 10" or a Decware DHM108B driven by a 250 watt plate amplifier.

The part I haven't worked out yet is, What is the best wiring for the given setup.

For aesthetics I need to place the big sub down at the Bay window side of the room, and the smaller subs near the TV end of the room. Each of the subs will have a plate amplifier, and I could drive them off of the high level output, summing the two rear channel speakers into the large sub, and drive the smaller subs off of the front R & L. The problem with this approach is I couldn't easily do the BFD since I it wants low level input/output.

I can fairly easily move the two small subs so that I could attach them to the Yamaha's sub out, but that leaves some questions;

1) If I am using the sub out feature of the HTR-5680, does that sum all 5/7 channels, and send only high freq to the other speakers? or does it just sum the front channels? If the latter I can do the BFD on the smaller subs, and hope proper placement will take care of the big sub.

2) Can I run the low level signal through 30' of #12 wire with good results? The wires are all running side by side in an area between the subfloor and the wall (which is all sealed up and impossible to get to now). Would I have a problem with signal induction from the High level speaker wires? If this works then I can do one channel of the BFD for the small subs, and one channel for the big sub.

Any other ideas on how to wire the subs?

Also any ideas on a good 10" driver that cost $110 or less that will work well in a sealed .68 cubic foot enclosure? I like the Decware because of its High efficiency, but the Titanic has good buzz among DIYer's.


BTW the method I am going to try for setting up the subs is to; (unless everyone tells me what a bonehead idea this is)

1) Graph & move one sub at a time to get proper placemment (within WAF).

2) Introduce BFD and EQ each sub independently.

3) Graph, adjust phase & tweak placement with all subs firing.

4) Do final tweaking of BFD with all subs firing.

[Chrisbee]

I'm sorry, but I can never understand the logic of buying much larger furniture to disguise the presence of loudspeakers and subs.
The finish on most modern equipment is first class. Way above the standard povided by modestly-priced furniture.

Speakers and subwoofers are highly developed transducers as well as nice furniture.
Many manufacturers spend ages perfecting their wares before releasing them onto an eager public.

If She doesn't like even a small subwoofer (like the 14" cube SB12+) then just throw a cloth over it (or several of them) and add a table lamp (or lamps)!

[brucek]

Any other ideas

With respect, the entire concept is frought with problems. I won't comment on the trunk idea - I can see problems there though.

The real issue would be that multiple subs will 'dumb down' to the weakest sub. Many people who have a small sub eventually get a larger one and want to use them both. It sounds like a good idea, but it's not. The challenged sub effectively lowers the output of the better sub in the frequency range where it's challenged. Your net result is not the sought after extended lower range of the better sub, but rather only increased dymamic range where the two subs compliment each other within their common capabilities. If you want mutiple subs, you need to use those with very similar extension.

The answer is a single larger sub that you can disguise simply by throwing a cloth over its head as Chrisbee suggests. Now it's a table.

1) If I am using the sub out feature of the HTR-5680, does that sum all 5/7 channels, and send only high freq to the other speakers? or does it just sum the front channels? If the latter I can do the BFD on the smaller subs, and hope proper placement will take care of the big sub

If you set any speaker on 'small', its low frequencies will be sent out the sub jack. Not so on large..

2) Can I run the low level signal through 30' of #12 wire with good results?

No. You need coaxial type cable for line-level signals.

brucek

[Ayreonaut]

If you have an adjacent crawlspace or attic, the best disguised is an Infinate Baffle subwoofer. Could you do it?

[aceinc]

Ayreonaut: This is S Florida, dig a basement and you have a swimming pool. The room is on the first floor with no IB potential.

brucek: One thought was to use the smaller subs with no bass boost which will have a natural roll off at about 40-50 HZ, and on the larger sub set the xover for as low as it will go. This would seem to have the advantage of reducing the amount of power needed by the big sub by reducing the the range it needs to cover. If I choose to use the smaller subs with a bass boost, I can probably get usable signal out of them down to 25- 30 hz, and some power even lower. I just need to match the curves to optimise all of the drivers.

Chrisbee: If you want a sub that will match the "style" of furniture that you have, where do you go to buy it? If we were in college we could put the speakers on the shelves that we built with cinder blocks and 1"x12" pine, and I could stuff a 12" driver into the wood wire spool I picked up at the power company that I'm using as a cofee table as well. The "style" of most speakers currently produced would be considered contemporary/modern, the style of this living room is somewhat eclectic, but generally traditional. While my wife & I disagree on the quantity of speakers, I do not disagree with her on the theme/style of the room, and I like the challenge of putting Subs in trunks.

I have a 12" sub that I built that is a 16" cube done in natural maple that is in my family room system. It looks quite nice and sounds great too, but for the living room which is bigger and a different decor it needs a different look. The trunks (new but antique looking) we have chosen will be gutted, and a mdf cabinet will be fitted inside and glued. The amplifier will be mounted on the back, and the speaker will be downfiring.

Thanks for taking the time to respond.

[Chrisbee]

Shame you can't manage an IB. A screen (or two) to taste and that's all you have in the room with no phase problems. I do agree that speakers and subs are very much a matter of taste. Thankfully the available range of veneers and finishes can make them almost invisible in many domestic situations. I prefer to use black boxes throughout but of course this is not a universal choice. It would be interesting to see pictures of the results of your "truncated" sub projects.

[aceinc]

Well I ordered two 10" titanics, and a dsp1124p. If I get finished a network upgrade that I'm doing this weekend with daylight left, I may try to knock out the cabinets.

What I have decided to do is, build the 10" Titanics into the .68 cubic foot cabinets with no amplifiers, place them at the bay window (rear channel) end of the room where I have the extra speaker jacks for subs, or biamping, and drive them with a 100 watt per channel NAD I have laying around. Using a splitter from the sub out on my Yamaha, I will feed it into the two channels on the BFD. I will take one channel of the BFD and split it into the two inputs on the NAD and drive each Titanic. I will use the BFD to provide any bass boost and of course to tame the peaks.

100 watts per channel seems anemic due to the fact I'm driving a small sealed enclosure, but if you believe the NAD hype, the NAD is underrated. Worst case I can always add some other amp later, if the concept seems sound but the power seems lacking.

If I am still dissatisfied with the results I always have the 3 cubic foot Trunk I can build the 15" Direct Servo and run it on the second BFD channel.

I will try to post pictures, which should be fairly uninteresting because if I do it right all you'll see is a antique looking leather covered trunk with a couple of binding post on the back.

[aceinc]

I was thinking, the NAD is probably rated at 100 WPC at 8 ohms, and the Titanic is a 4 ohm driver, so I may get a bit more than 100 Watts into each sub.

Doesn't look like this network install is going to cut me any slack.... So I may not get any wood cutting done this weekend...

Paul

[F1 fan]

Hi Paul,How do you like your NC ECHO'S?To bad that they are no longer selling these kits as they appear to be great little speakers and you can put together a full 5 channel setup for a very reasonable price.

.68cu ft seems a bit small to get any reasonable bass extension out of a 10 incher so you will probably need to add some boost.

You can expect your NAD to deliver at least 150WPC into a 4ohm load.

[Brian Bunge]

For the larger sub you could always build something like this:



I used this for a couple of years as an end table. It housed a Adire Audio Tumult with an outboard Crown K2 for power, an LT circuit to boost the low end and a BFD to help flatten in-room response. It ended up being flat to 10Hz in room.

[F1 fan]

Nice looking WAF approved design Brian ,may I ask how you made the legs?

[Brian Bunge]

Thanks! The cabinet is an 18" cube, double walled, for a 15" internal cube. The legs are simply 2 pieces of 22" long MDF glued and nailed together. I then rounded the outside corner and the inner edges of the legs before veneering them with cherry veneer. The legs are attached with construction adhesive and screws going through from the inside of the cabinet. The top is 1.125" MDF shaped and finished with a faux marble painted on finish.

[F1 fan]

I admire your veneering skills. I don't think I could properly wrap it around the corners and edges like that.

[Brian Bunge]

Applying the veneer wasn't that bad. Trimming it, on the other hand, was a real PITA!