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alexperl
07-06-2005, 09:04 AM
Hi...
I built 2 ar.com's, i am thinking to build a home cinema.
Can i use a ar.com bookshelf speakers for a center?
Or it will be much better to build a speaker with a center crossover?
And what the difference betwen center and a bookshelf?
Thank you...

kexodusc
07-06-2005, 09:27 AM
alex, you have a few options:

If you have a large RPTV, Plasma, or DLP TV, you don't have to worry about shielding the speaker from the TV, so another Ar.com would work fine as a center channel. (the ar.com are not magnetically shielded and could screw up the picture while watching). If you have a normal CRT television then the speaker should be about 1.5 feet or more from the screen.

I used and AR.com lying on it's side for awhile and it worked fine. In my case, I have 3 seats across the room, and as you moved out of the center sweet spot, the sideways ar.com speaker didn't sound right IMO, but sounded perfect if I was sitting in front of the TV or just off 2 or 3 feet to either side/

If you want a timbre matching, typical center channel that has 2 woofers and a tweeter, you can contact Ed Frias and inquire about his extensively modified EFE BIC DV-62CLRS center channel. Drivers are tested and matched and a whole no crossover is made so that it matches the ar.com speaker. It's not very expensive and sounds much better than you'd think. I bought one for myself and a family member I built the ar.com's for, and I am quite happy, it tends to fill the room with more sound, though there can be off-axis lobing problems in some spots, it's a better trade-off to me than the sideways ar.com.

I also just recently tried standing an ar.com upright (not sideways) for a center channel and found it to be even better than being sideways, but it looked a bit funny. All in all I think this is the best way to do it if you don't mind a tall silly speaker on your tv, but if you need a shielded speaker, contact Ed Frias.

Most center channels you see have the woofer-tweeter-woofer alignment. This is actually not a very good way to make a speaker, they tend to have off axis lobing problems. Not a problem if you sit right in front, but move off axis and things can start to happen. The trade off is they benefit from increased sensitivity sometimes and can "fill" the room with more sound IMO. In a perfect world, you'd have 5 identical speakers for home cinema. Sometimes speakers are to big to fit nicely on a tv though, so shielded, center channels were made.

alexperl
07-06-2005, 09:31 AM
Thank you for your answer..

oddeoowphil38
07-06-2005, 07:57 PM
Thanks Kex you already ansered one of my questions I just asked a few minutes ago. Does Ed Frias have something todo with BIC speakers? His name gets tossed around a lot. Where did you get the BIC DV-62CLR's??? What does Ed actually do??? Just change the X-over and use the BIC drivers??? Also, if you put an AR.com on your tv vertically you could always angle it down with door stoppers. Wouldn't that help too???

kexodusc
07-07-2005, 06:23 AM
Thanks Kex you already ansered one of my questions I just asked a few minutes ago. Does Ed Frias have something todo with BIC speakers? His name gets tossed around a lot. Where did you get the BIC DV-62CLR's??? What does Ed actually do??? Just change the X-over and use the BIC drivers??? Also, if you put an AR.com on your tv vertically you could always angle it down with door stoppers. Wouldn't that help too???

Ed Frias is the owner of EFE Technology speakers, a smaller boutique speaker company. His EFE line is a good step up on $1000 or less speakers, though he has a few inexpensive models. For sub $600/pair speakers though, he's found it easier to buy a bunch of BIC America speakers from them and then basically rebuilds the whole speaker to voice match his other designs.
I'm not 100% sure, but the BIC drivers look an aweful lot like Vifa's to me (if not their damn good knock-offs). The drivers are all measured and matched to each other (something even Paradigm doesn't do), and the crossover is completely remade with higher quality parts. I think a better terminal is inserted too if I remember correctly.
The crossover is really the heart of the speaker system, I've heard speakers with excellent high-end drivers sound rather bland compared to inexpensive drivers with an excellent crossover. Crossovers change the entire frequency response curve, tonality of the speaker and presentation. Lots of speakers witht he same drivers sound incredibly different.

The EFE modified 62-CLRS is a good inexpensive speaker. I posted a review on mine you should be able to find under Bic. I wouldn't say it was as good as my Studio CC, but it was definitely better than the CC-370 I borrowed. It's definitely built better than the CC-370, 5/8" MDF, quality xo parts. But the charcoal black finish is kind of ugly so I stripped and veneered mine to match my ar.com's.

A veritcal ar.com angled works fine, in fact, it's probably best in most situations except it's not shielded. I just find that it's overall sound output is diminished when I sit on either of the two seats I have on the sides of my room. My room is quite big though, 20 X 24 and the side seats are quite a bit off axis, I'd say 8 feet or more each way.

PAT.P
07-07-2005, 08:28 AM
Kexodusc Is there any good book that shows how to built your own speakers,choosing drivers and crossover ect ect .Thanks Pat.P

kexodusc
07-07-2005, 09:27 AM
Kexodusc Is there any good book that shows how to built your own speakers,choosing drivers and crossover ect ect .Thanks Pat.P
For beginners, I recommend:

Loudspeaker Design Cookbook - Vance Dickason
Designing, Building, and Testing Your Own Speaker System - David Weems
Great Sound Stereo Speaker Manual - David Weems
Speaker Building 201 - Ray Alden

The last one is on sale right now at Parts Express for today only.
I'd start with SB201, and Designing/Building by David Weems.
Then the Loudspeaker Design Cookbook.

If you already have a good grasp on electronics and speaker mechanics, you could get the Vance Dickason book right away - it can be a tough read at times.

Tons of information available on the web if you do a google search, Parts Express's site and Web Forum are a good place to start.

PAT.P
07-07-2005, 06:57 PM
Kexodusc Thanks will look into these book and after will see if Im up for challenge.I got a radial arm saw and all blade to make groove for the box.Im a jack of all trade master of none.Pat.P :D

hmmmm
07-08-2005, 03:39 AM
alex, you have a few options:

If you have a large RPTV, Plasma, or DLP TV, you don't have to worry about shielding the speaker from the TV, so another Ar.com would work fine as a center channel. (the ar.com are not magnetically shielded and could screw up the picture while watching). If you have a normal CRT television then the speaker should be about 1.5 feet or more from the screen.

I used and AR.com lying on it's side for awhile and it worked fine. In my case, I have 3 seats across the room, and as you moved out of the center sweet spot, the sideways ar.com speaker didn't sound right IMO, but sounded perfect if I was sitting in front of the TV or just off 2 or 3 feet to either side/

If you want a timbre matching, typical center channel that has 2 woofers and a tweeter, you can contact Ed Frias and inquire about his extensively modified EFE BIC DV-62CLRS center channel. Drivers are tested and matched and a whole no crossover is made so that it matches the ar.com speaker. It's not very expensive and sounds much better than you'd think. I bought one for myself and a family member I built the ar.com's for, and I am quite happy, it tends to fill the room with more sound, though there can be off-axis lobing problems in some spots, it's a better trade-off to me than the sideways ar.com.

I also just recently tried standing an ar.com upright (not sideways) for a center channel and found it to be even better than being sideways, but it looked a bit funny. All in all I think this is the best way to do it if you don't mind a tall silly speaker on your tv, but if you need a shielded speaker, contact Ed Frias.

Most center channels you see have the woofer-tweeter-woofer alignment. This is actually not a very good way to make a speaker, they tend to have off axis lobing problems. Not a problem if you sit right in front, but move off axis and things can start to happen. The trade off is they benefit from increased sensitivity sometimes and can "fill" the room with more sound IMO. In a perfect world, you'd have 5 identical speakers for home cinema. Sometimes speakers are to big to fit nicely on a tv though, so shielded, center channels were made.
Kexo,
maybe this is a dumb question, but could you use two ar.com's for the center speaker spread them a small distance apart and bi-wire them?

kexodusc
07-08-2005, 04:27 AM
Kexo,
maybe this is a dumb question, but could you use two ar.com's for the center speaker spread them a small distance apart and bi-wire them?

Hey Hmm, long time no chat.

I know a few people that use 2 speakers for center channels, but IMO, why not just use the main speakers running in "phantom mode", and rely on the center image? You'd relying on the same thing.

If you "bi-wire", you're essentially cutting the impedance in half, not great for some receivers. You'd also get some serious horizontal lobing, especially with 2 tweeters, as you move off-axis. In the sweet-spot (or close) it probably wouldn't matter.

You could certainly do it, but the cost/benefit is pretty low IMO, as it wouldn't sound any better than 1 speaker, could possibly sound worse, possibly introduces some impedance issues, and costs double.

The two people I know who do it have reasons. One has projector for his HT, and instead of a floor mounted center channel, or having one behind the screen, decided to use two towers on either side - he againd relies on imaging, but his freakin' HT room is over 700 square feet and you're so far back that lobing isn't much of an issue.
The other guy has a plasma and got a good deal on some on-wall speakers so opted not to run 1 center channel.

Unless you've got environmental reasons though, I can't imagine it being worthwhile.

hmmmm
07-08-2005, 05:01 AM
[QUOTE=kexodusc]Hey Hmm, long time no chat.
Thanks Kexo,
I've been pretty busy lately and will be gone all of next week also. I did manage to finish a simple behind the sofa bar - I wanted to get it done before football season.
I was just curious about the center channel because I've seen it in a couple of high end audio shops, but they were specifically designed for that setup. I'm working on modifying my speaker stands and later this year will try to build another set of speakers. I'll probably try doing some wood bending...been reading up on it a bit.
Take care!