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Tarheel_
07-20-2005, 04:13 AM
a few years ago, i sold my Polk fronts and center and spent all my budget on a used pair of F30s. That was the good part, bad part is no money for a center. So, after much research I decided to buy a pair of matching bookshelfs and use one as a center -vs- a dedicated center.

my problem is space, am i losing something by placing a bookshelf on its side? I could move it upright, but the tweeter would be much higher than my ears and move than a foot above the L/R front tweeters?

Sir Terrence the Terrible
07-20-2005, 04:55 AM
a few years ago, i sold my Polk fronts and center and spent all my budget on a used pair of F30s. That was the good part, bad part is no money for a center. So, after much research I decided to buy a pair of matching bookshelfs and use one as a center -vs- a dedicated center.

my problem is space, am i losing something by placing a bookshelf on its side? I could move it upright, but the tweeter would be much higher than my ears and move than a foot above the L/R front tweeters?

The only problem I see is the person that sits on the left side of the couch will here more treble from the center than a person sitting on the right side. The person on the right side will here more bass from the center than the person on the left. Aside from that, I cannot see a problem with what you did. Be careful of any cabinet induced reflections or you will hear first hand the sound of boudary reinforcement.

Nice system Tar type dude!

Tarheel_
07-20-2005, 05:14 AM
thanks for the complement Sir TT....actually, it was mainly your advise that steered me toward a matching bookshelf -vs- a dedicated center. Plus, i'm able to sell the other speaker and come out way ahead.

I did angle the center downward and must say the front array is now seamless . The phantom center worked well...at least in the sweet spot, but now i hear more detail from a true center.

Swerd
07-20-2005, 05:56 AM
am i losing something by placing a bookshelf on its side? I could move it upright, but the tweeter would be much higher than my ears and move than a foot above the L/R front tweeters?Using a 2-way bookshelf on its side is actually less of a problem than using an MTM on its side. The MTM design was intended to solve some dispersion problems in the vertical dimension introduced by 2 drivers working at the same frequencies. It is meant to be stood vertically. The picture shows the interference pattern you can get when there are 2 similar drivers mounted side by side. For simplicity the tweeter is not shown. You can really see the lobing effect. So with a center channel MTM, where you sit becomes very important.



http://members.aol.com/pjay99/tank-mtm.jpg



I found this picture and others at http://members.aol.com/_ht_a/pjay99site/speakerhome.html and click on the link for Sound Wave Renderings on the list on the left side. It uses a series of these sound wave diagrams to simply describe some of the problems of sound dispersion with various speakers. It is worth a quick read.

poneal
07-20-2005, 06:36 AM
Nice graphical representation of lobes. Kinda makes the eyes go buggy but gets the point across.

kexodusc
07-20-2005, 06:45 AM
Yep, that's a very simple picture that shows what's bad about Horizontal MTM speakers as center channels...unless of course you're sitting in the sweet spot all the time, then I guess it doesn't matter.

Sir Terrence the Terrible
07-20-2005, 08:41 AM
Now you guys see why I went to all the trouble of elevating my RPTV so I can setup my center speaker vertically.

I understand manufacturer doing this kind of setup for WAF, but it is not the best design for the duty it is ask to do. I think this is why so many people have dialog intelligibility issues on soundtracks.

SlumpBuster
07-20-2005, 12:22 PM
When I was still in school I couldn't afford a dedicated center, but I had two cheap B&W bookshelf speakers. I used them both as a center wiring them in series. I could place them vertically or horizontally. I got good results, at least to my ear. But that was with a prologic receiver, not DD or DTS. So you may not want to be so quick to sell that extra speaker. Plus, you could always use the extra for 6.1 surround if your not already running extra surround channels.

StanleyMuso
07-20-2005, 06:11 PM
I hate acronymes.

Sir Terrence the Terrible
07-21-2005, 03:49 AM
I hate acronymes.

Actually WTW would be more accurate. That would be woofer/tweeter/woofer, two woofers side by side with a tweeter sandwiched in between. MTM would be midrange/tweeter/midrange but that midrange handles the bass frequencies also, that is why woofer/tweeter/woofer might be better than MTM. I know you hate acronymes, but its not good to be a hater(sorry I couldn't help myself.)

Tarheel_
07-21-2005, 04:25 AM
Plus, you could always use the extra for 6.1 surround if your not already running extra surround channels.

You make a great point....i currently use monopolar rears and if i purchased another pair (to replace them) then i would have matching 6 speakers....man that would sound nice.

Although, i sold the idea to the other half with the intent on selling the other...but my plans may have just changed. Hey, my doghouse is the HT room...not a bad place to crash.

Sir Terrence the Terrible
07-21-2005, 04:49 AM
Yo Tarheel,
How do you run your left and right mains? Large? Small? In know these speakers have a pretty good bass response, just curious.

Tarheel_
07-21-2005, 06:56 AM
Yo Tarheel,
How do you run your left and right mains? Large? Small? In know these speakers have a pretty good bass response, just curious.

i run them Large and switch the cutoff between 40 and 80....the bass really misses something on 60.

my HK AVR allows bass management for each input and surround format...so i've experimented and found overall 40 is best.

The fronts do produce some great clean bass, but for DVDs i had to add a sub. So i bought a used 15" Def Tech TL+ and it really slams.

I doubt my setup is optimal (sp?) but the Feedback Destoyer seems too complicated. I've used the S&V calibration disc as best i could.

nick4433
07-21-2005, 08:33 AM
Tar, hate to be funny dude but the only thing wrong with the pic is the damn picture quality. Did you take that on your cell phone camera or something?

Tarheel_
07-21-2005, 08:50 AM
Tar, hate to be funny dude but the only thing wrong with the pic is the damn picture quality. Did you take that on your cell phone camera or something?


nick, that's funny, but the pic is high quality, but the site doesn't allow anything over 700x700....so i had to reduce the image and the quality went with it.

don't know much about cameras so not sure of a another way

StanleyMuso
07-21-2005, 08:56 PM
Thanks for the explanation. I "hate" to be un-enlightened.:p