Cheap design for large room

[chrish]

Hello fellow DIYers. I am looking for a little advice on choosing my next speaker project.

Some background: I was at a friends house and noticed that she had a dusty old amplifier sitting under a table, so I asked her if there was something wrong with it. The answer was that it did not work... being a nice guy, I said I would have a look at it for her and see if I could get it going. It was an old Kenwood amp, probably 15 or more years old. With a little work I was able to get it going for her., and I am guessing around 30-40 watts per channel. Well after fixing it, she said that was great, now she needed some speakers, and asked me what she should buy. Well, before I knew it, I had volunteered to build her a pair of speakers. I said I would build them, but I would leave the finishing work up to her.

My friend is an interior designer, so I am looking for a speaker project that is not too ugly. The problem is, my friend's apartment is an old wharehouse conversion, with a living area of about 8 metres by 16 metres with high ceilings and wooden floorboards. She likes listening to chillout music, contemporary, and a little dance music. I warned her that she would probably not get away with bookshelf type speakers with that amp and living area volume.

I live in Australia, so a design using popular-easily obtainable parts would be a help. Also, I have a very well equipped woodworking workshop, so ease of construction is not a high priority. Big priority, however, is cost. Do not really want to spend more than a couple of hundred on these if I can.

Saw this design on another thread http://murphyblaster.com/content.php...ifa_Tower.html
it looked promising, but any further advice would be greatly appreciated.

Thanks,

Chris

[joensd]

Hi,
sounds like a big task that room.
Anyway you should be able to find some cheap floorstanders
that will give a nice sound.

The design you link to I do not find particularly cheap so it might be worth looking around a bit.

Can you get hold of Monacor speakers?
If so you could look at the mindstorm:
http://www.lautsprechershop.de/hifi/...hifi/ct213.htm
It´s a transmission line with a very simple crossover;1 coil, 1 capacitor.
The drivers are also quite cheap and in my opinion these are some nice speakers for chillout. The bass coming out of these is real amazing.
If the building plan is not available I´ve got it somewhere.

You´ll find speaker projects with Dayton speakers have a good price/quality ratio as well(haven´t heard them though):
http://www.wadsnet.com/~dtenney/

and many more...

greets

[bigwill]

How about some Beta 12lts (with a tweeter) or a beta 12cx in big vented cabinets, seeing as they're about 100dB efficient?

[AJinFLA]

Hi Chris,

No first hand experience with these kits, but, they are quite high in efficiency (30 watts should get fairly loud, even in the large room), relatively cheap and perhaps most importantly, the drivers should be available down under.
http://www.pispeakers.com/catalog/pr...products_id/36
Perhaps you could purchase just the plans online.
Should provide good value. Plently loud and probably quite civil with the nice Vifa tweeter involved. Good luck.

Cheers,

AJ

[mgoedeke]

That is a very large room indeed, especially for 40 wpc. How about one of the larger P.Audio co-ax units or simpler yet, the Selenium ones with the piggy-backed crossovers? Floorstander as wide as the speaker (12"/15"), and other dimetnions to suit a large-ish bass-reflex tuned 40-50Hzish. I'd forget about 8"/1" sepakers in a room that size for anything but quiet background listening.

[PeteMcK]

Chris,
check out the 8" & 10" poly cone drivers that Jaycar has
with tweeters & xover just over your budget;
(2x8" > MTM or 2.5 way)
However, if you have an ABN, you can get Peerless or Vifa from WES at around the same price

[chrish]

Thanks for taking the time to reply guys. I think I am happy to stretch the budget to consider Vifa or equivalent. They are reasonably easy to source here in Aus. Also should have mentioned that out of consideration for the neighbours in the appartment complex, loud listening levels are not required. Also, although the room is large, it is the entire living area, and any serious listening would be close to the speakers, anywhere else in apartment only background music would be the requirement.

Thanks again for your input,

Chris

[chrish]

Ah... PeteMcK, the friend I am making the speakers for owns her own homewares store and runs an interior design business and obviously has an ABN. Does the ABN have to be for an electronics or hifi business or will any ABN be OK? If it is OK it may help considerably...

Thanks,

Chris

[69stingray]

I had two thoughts come to mind, and that is what they are, only thoughts.

For a large room, maybe the approach of several small speakers would better. Possible 5-6 2-way high sensitivity monitors with a subwoofer in the corner. I am thinking of a 5-1/4" with an inexpensive tweeter.

Second idea, I recall reading somewhere that for large sound, you want to use as large drivers as possible. Also, an open baffle set-up gives an inherit "dipole" effect which may or maynot be better in a large space. Maybe doing a cheaper clone of the Legacy Whisper speaker. Instead of four (4) 15" woofers, just two (2) 15" woofers (or even 8") on and open baffle, with four (4) midrange with a sealed enclosure and a passive radiator.

May want to look at the Orion design also for some ideas. Lots of great info on the Linkwit Lab website!


Legacy Audio's Whisper Speakers


Linkwitz Lab's ORION Loudspeaker System

[Scottmoose]

I'll stick my neck out here. Martin -I beg your forgiveness! This is the one I'd go for, for big rooms on a tight budget: Terry Cain's Bigger Is Better TQWT. At 70" high, it's very tall, but it's also very slim, being only 7" wide, and can be made to look extremely elegent. This is the original: http://melhuish.org/audio/DIYTQ8.html

Predicted response is invariably ragged, but it smooths out in room, because it's one of the few speakers that is deliberately designed to activate as many room-modes as possible, which in a big space can be quite useful. Now, as a rule, I'm with Linkwitz -you should try not to activate room-modes at all if you can avoid it. Unfortunately, that's very expensive in terms of speaker drivers, active crossovers equalisers and amplifiers. Therefore, on a budget, you can't really avoid activating room modes, especially in a big room, so I'd go to the other extreme, and take as much advantage of room-gain as possible.

What can I say -the BIB is one of those designs which simply shouldn't work, but does, and sounds good, especially in large spaces, if pushed back against a wall, or better, in corners. (I've tried it). Use with either the Fostex FE167E, or, better, the FF165K with a rearward firing tweeter. Sings from a different song sheet, and has different priorities to most speakers, but it's none the worse for that. With either of those drivers, you're going down to 30Hz or lower in a large space. And being single drivers, they're going to work nicely in the nearfield too. And with 35 - 40w available, you can add some series resistance or BSC if needed without worrying about them becoming difficult to drive -they're about 95db sensitive.
Cheers
Scott