Mixing center and surrounds?

[icor1031]

I'm considering getting 4 of those Dayton bookshelf speakers for front L/R and rear L/R on my T.V.

However, I don't want to spend $60 for their center when the others are only $15/ea ($30/pair).

Is it a bad idea to build a center and use it with those 4 bookshelf speakers? i.e. will mixing make it sound bad in some way?

Thanks.

[dtkeith]

I don't think it would sound bad. The 'ideal' set up is to have your front stage all the same drivers, but until recently I was using a completely different center with my towers, and it was fine.

[icor1031]

:)

And I'm only changing the center. Voices are almost always in the center AFAIK, so shouldn't be a big deal I assume.

Why do most people use Two mids in their centers?

[Whitneyville1]

Just get 3 pairs of B652s and you have fronts, backs, center, and back center, or a "spare". At $27.80 a pair, I bought my three pair as "test beds" and when I get some accurate (better than my Audessey) measurements of my "improvements", I'll post them here and hopefully on the Projects Showcase. They really aren't "pigs", but like any "budget" speaker, they were "built to a price-point". For not much money, they can be greatly improved. In a MUCH larger ported enclosure, the woofer sims out pretty well, as long as it's XO'd about 5Khz where it gets kinda strange. Just don't wall mount them, or the lower mids get "muddy". I'll make you a heck-of-a-deal on a pair of Goldwood 4" shielded 8 ohm speakers, that with a Nuance TW5-073LR (279-060) tweeter and a single crossover capacitor and resistor would make a decent center channel speaker @ 4 Ohms.
The "reason" for two mids is most sound is in the "midrange" (voice or music) and twin mids "spread" the sound more evenly over the listening area (think sofa instead of single easy chair). It seems to work, like the "sound bars" with a dozen or more 2"-3" drivers under a 50-70" mega-screen TV.

[icor1031]

I considered using 5 of them, but my hesitancy is because it would look weird.

My receiver uses 8 ohm.

[Whitneyville1]

Just lay the center on it's side, and put one in the closet. Plan B would be to get a couple of the Aura 3" 4 ohm full-range speakers for $12.50 each from Madisound and build them into a 5-6 liter box for a center channel in series for an 8 ohm load. That would be as much as a pair of B652's, and if you buy 3 pairs of B652's, the S&H will be free. Cross them to your sub at about 80Hz, and you may be very pleasently surprised.

[lunchmoney]

:)

Why do most people use Two mids in their centers?

When in an MTM configuration (mid-tweeter-mid) it's only for visual symmetry. Serves no other function. In fact, it's typically a bad configuration for a speaker on its side unless the tweeter is crossed quite low (Tritrix for example).

Two woofers vs one does mean less distortion since each of the two woofers only has to work half as hard to achieve a given volume. But the relationship of the tweeter to the woofers causes issues that I won't dig into here... not disastrous, but certainly less than ideal.

When in a WTMW configuration (tweeter above the mid, woofers on either side), these issues are alleviated.

Anyways, typically there is nothing inherently wrong with tipping a TM on its side. It's not a bad idea to move the tweeter as close to the woofer as possible though, and tweaks to the crossover are usually beneficial.

Here's my TM center channel, visually asymmetrical (I really dig the look actually), but not even a hint of asymmetrical sound. I call it the Blackbird, it's a Zaph SR71 optimized for center channel use:

http://i249.photobucket.com/albums/gg210/djnelsen1/6fd7234a.jpg

I'd recommend that you simply get a 5th TM, tip it on its side, and see how you like it. For the price, it's low risk. If you don't like it, then let's revisit other options...

Hope this helps.

[fbov]

Just get 3 pairs of B652s and you have fronts, backs, center, and back center, or a "spare". ...

+1 but I'd keep the center vertical if you can; Lunch's sideways MT is neither a sideways SR71 nor a chance design. It's designers getting together to fill a new application niche properly.


The "reason" for two mids is most sound is in the "midrange" (voice or music) and twin mids "spread" the sound more evenly over the listening area ...
Quite the opposite, I'm afraid. Poorly designed sideways MTMs cause big gaps in the sound that vary by seat and frequency.

When in an MTM configuration (mid-tweeter-mid) it's only for visual symmetry. Serves no other function. ...

Sorry, but you're also way off.

Vertical MTMs, aka D'Appolito configurations, have several advantages over an MT
- 2x power handling
- 2x sensitivity per Watt
- 4x voltage sensitivity (what you'll see connected to your amp/AVR)
- reduced sonic energy directed toward floor and ceiling, reducing room interaction and improving imaging at the speaker
- increased sonic energy in a wide horizontal pattern at tweeter level, for a more uniform sound field and less variation in sound from one seat to another.

These last two are a result of MTM geometry, specifically wave interference from 2 point sources. These are advantages vertically, but disadvantages when the MTM is mounted horizontally, as with most CC applications.

Lunch's point about needing a low XO frequency (in addition to low driver C-C spacing), is so you cross over at a frequency below were the drivers interact to form the interference patterns that cause the last 2 features.

Sorry to digress, but the OP deserves a better answer.

HAve fun,
Frank

[Sydney]

Vertical MTMs, aka D'Appolito configurations, have several advantages over an MT. Well put Frank...
In the 70's I got tired of the usual practice of having to attenuate a tweeter with a single woofer/mid and tweeter implementation and instead began using 2 woofer/mids paralleled to match tweeter sensitivity.

[lunchmoney]

+1 but I'd keep the center vertical if you can; Lunch's sideways MT is neither a sideways SR71 nor a chance design. It's designers getting together to fill a new application niche properly.


Quite the opposite, I'm afraid. Poorly designed sideways MTMs cause big gaps in the sound that vary by seat and frequency.


Sorry, but you're also way off.

Vertical MTMs, aka D'Appolito configurations, have several advantages over an MT
- 2x power handling
- 2x sensitivity per Watt
- 4x voltage sensitivity (what you'll see connected to your amp/AVR)
- reduced sonic energy directed toward floor and ceiling, reducing room interaction and improving imaging at the speaker
- increased sonic energy in a wide horizontal pattern at tweeter level, for a more uniform sound field and less variation in sound from one seat to another.

These last two are a result of MTM geometry, specifically wave interference from 2 point sources. These are advantages vertically, but disadvantages when the MTM is mounted horizontally, as with most CC applications.

Lunch's point about needing a low XO frequency (in addition to low driver C-C spacing), is so you cross over at a frequency below were the drivers interact to form the interference patterns that cause the last 2 features.

Sorry to digress, but the OP deserves a better answer.

HAve fun,
Frank

Hold up... I was referring to issues with horizontal MTM's used as center channels, not vertical MTM's. I should have been more clear.

And I only suggested laying the TM on its side as a center because vertical space is very often a problem with center channels, I assumed he has the same issue.

[generic]

I don't want to try and talk you out of anything, but you might want to read some independent testing on those before you spend the money.

http://www.zaphaudio.com/Dayton-B652.html

IMO, they don't seem HT worthy. Perhaps garage,den, or portable music.

Pioneer,Yamaha, and Infinity have some good offerings at fair prices. Perhaps more then those Dayton's, but it would be better to buy the right thing the first time.

These might work as well, I bet they would sell you just one, if you asked.
http://www.madisoundspeakerstore.com/2-way-speaker-kits/aurasound-ns6-speaker-kit-8-ohm-woofer-parts-only/

As far as the center not matching. I think it could be rather noticeable if the speakers aren't even close. I lot of voices and sound effects pan from side to side and blending in to the center channel along the sound path. If the center doesn't match, it will sound different. The rears are the ones that aren't as important, but the front three should match.

[lunchmoney]

As far as the center not matching. I think it could be rather noticeable if the speakers aren't even close.

Absolutely.

Years ago my center was very different from my mains.

I always knew it wasn't great, but didn't realize how much it sucked until I had L/C/R that matched.

[icor1031]

It is, it needs to lay down.

Thanks, gents.


Hold up... I was referring to issues with horizontal MTM's used as center channels, not vertical MTM's. I should have been more clear.

And I only suggested laying the TM on its side as a center because vertical space is very often a problem with center channels, I assumed he has the same issue.