Center channel speaker separation?

[Deleted]

Mar 21, 2016 8:10:20 GMT -5 smarties said:

Q75/Q95
Ref 2.2/200 (model the 1990's)

It was blindlily obvious of the poor SQ of the Q95C. All speakers set to small.

Sorry, all these are quite old models.  Still slightly confused.  Back in the 1990's the center channels tended to be undersized.  The Q95C is the correct match for the Q75 but it is 4 ohms (what amp were you driving it with).  It does have the same tweeter.  The 200C is a much larger Ref center.  Not sure what the Ref 2.2 is for?

Anyway, my comments about center speakers matching timbre wise,power handling and driver for driver is most relevant to more current models in most brands.  Even Klipsch in the 90's didn't have very close matches in some of their centers.

[KeithL]

Double Advents - now that's going back quite a ways.

Personally, I seem to recall the original Advents as having plenty of bass - and going pretty low pretty flat with their funny woofer. What they lacked was in the tweeter. The woofer was quite heavy, and so didn't extend very high, and the "orange peel" ring-plus-dome tweeter/midrange both didn't extend very high, and was a little weak in the lower midrange. This actually left them sounding quite neutral - except for a lack of very high end and a bit of a hole in the midrange. The Advents were sealed air suspension speakers, 8 ohms, and not especially efficient. So, by paralleling a pair of them, you ended up with 4 ohms, which coaxed more power from most solid state amplifiers, got more cone area for the bass (they were actually quite flat well into the low bass - but didn't have enough cone area to make huge amounts of low bass), and increased the efficiency a few dB. (Remember that, in order to double them, the top pair had to be placed upside down - so the tweeters were close together.)

Advents and Klipsch speakers are about as far apart in sound as two speakers can get - and which you like is a matter of personal preference (I personally prefer the Advents).

The main argument AGAINST using a pair of speakers for a center channel speaker is the comb filter effect. If you place two identical speakers side by side, and play the same signal through both, you get an interference pattern (called a comb filter effect). As you move your head from side to side the signal gets louder and quieter - in a pattern like the teeth of a comb. (The pattern varies with frequency, and with the distance between the speakers, but the "teeth" are between a few inches and about a foot apart - and can be quite noticeable if you move your head from side to side.) If you stack them vertically, then the pattern is vertical, so each frequency gets louder and softer as you move your head up and down. Most properly designed center speakers that use two midranges with a tweeter between them ("m-t-m pattern") actually don't feed the same signal to both midranges - rather they frequency-limit the signal to one midrange to reduce this effect.The real point is that any well-designed center speaker is going to take all of this into account, and simply putting two speakers side by side does not.

It is almost always a good idea to have a center channel speaker that is matched to the front left and front right speakers. A different center channel speaker that has more midrange will make dialog that comes from the center more easily intelligible, but isn't going to work well for anything that's supposed to pan smoothly from side to side, or that's supposed to be located somewhere off-center in the front. Likewise, some speakers have similar vertical and horizontal dispersion patterns, and so can be placed either vertically or horizontally, some are designed specifically to be mounted one way or the other - and don't work well if you use them the other way. Another thing to keep in mind is that the horizontal and vertical dispersion you WANT from a speaker will depend on the room itself, and your speaker layout. For example, a center channel speaker with a wide horizontal dispersion will tend to give you a wider sweet spot, but, if your room is live, will tend to give you a less precise center location for dialog (more sound bouncing off the side walls). A center speaker with a narrow horizontal dispersion will give you a narrower sweet spot, but will tend to lock the image in more tightly to the center.

[smarties]

Q75 was 6ohm. Using dedicated amps not AVR. Reference Model 2.2 are floorstnaders.

The 200 made the cinema sound better, I let two people borrow the 200 they had Q95 and they sold the Q95 within a week.

[Deleted]

Monku says,

Now I am using three Ascend Sierra 2's across the front, all vertically positioned and it sounds great. My feeling is the center does not necessarily have to be the same model as the sides or even the same brand as the sides and while ideally there should be a timbre match, if it sounds good to you then that's what counts. The main thing is to not overthink or try and be elaborate when simple is just as good or better.

So Monku why don't you go out and buy center speaker from a different brand install it and see what you think?  I'm sure the fact that all three identical Sierra 2's sound great is just a coincidence.   


Great, I've changed my mind.  I'm now going to sell my 5 timbre matching speakers (they all have the same exact tweeter and mid/woofer) and go out and find 5 speakers that really sound nice by themselves but not necessarily the same.  I'll place them where they look good and have a new idea for the industry.  I'm sure it will be all the rage and a very popular fad.  (joke, OK)

[smarties]

again just depends. I wouldn't like to use the same speakers I have for LR as I do for sides and rears. Also they wouldn't fit as center

[geebo]

Mar 21, 2016 10:07:44 GMT -5 @chuckienut said:

Monku says,

Now I am using three Ascend Sierra 2's across the front, all vertically positioned and it sounds great. My feeling is the center does not necessarily have to be the same model as the sides or even the same brand as the sides and while ideally there should be a timbre match, if it sounds good to you then that's what counts. The main thing is to not overthink or try and be elaborate when simple is just as good or better.

So Monku why don't you go out and buy center speaker from a different brand install it and see what you think?  I'm sure the fact that all three identical Sierra 2's sound great is just a coincidence.   


Great, I've changed my mind.  I'm now going to sell my 5 timbre matching speakers (they all have the same exact tweeter and mid/woofer) and go out and find 5 speakers that really sound nice by themselves but not necessarily the same.  I'll place them where they look good and have a new idea for the industry.  I'm sure it will be all the rage and a very popular fad.

For the best results get three matching speakers for front, center and left and put them all in the same place...

[monkumonku]

Mar 21, 2016 10:07:44 GMT -5 @chuckienut said:

Monku says,

Now I am using three Ascend Sierra 2's across the front, all vertically positioned and it sounds great. My feeling is the center does not necessarily have to be the same model as the sides or even the same brand as the sides and while ideally there should be a timbre match, if it sounds good to you then that's what counts. The main thing is to not overthink or try and be elaborate when simple is just as good or better.

So Monku why don't you go out and buy center speaker from a different brand install it and see what you think?  I'm sure the fact that all three identical Sierra 2's sound great is just a coincidence.   


Great, I've changed my mind.  I'm now going to sell my 5 timbre matching speakers (they all have the same exact tweeter and mid/woofer) and go out and find 5 speakers that really sound nice by themselves but not necessarily the same.  I'll place them where they look good and have a new idea for the industry.  I'm sure it will be all the rage and a very popular fad.

Don't forget to post your review/impressions of your new non-matching speaker system in the Lounge!

While I personally think you can't go wrong with making sure your speakers are all timbre matched (and the easiest way to do that is to just have them be all the same model), if someone else is happy with "mismatched" speakers then who am I to tell them otherwise? Whatever enables you to sleep peacefully at night is what I say.

[smarties]

Mar 21, 2016 10:23:23 GMT -5 monkumonku said:

Mar 21, 2016 10:07:44 GMT -5 @chuckienut said:

Monku says,

Now I am using three Ascend Sierra 2's across the front, all vertically positioned and it sounds great. My feeling is the center does not necessarily have to be the same model as the sides or even the same brand as the sides and while ideally there should be a timbre match, if it sounds good to you then that's what counts. The main thing is to not overthink or try and be elaborate when simple is just as good or better.

So Monku why don't you go out and buy center speaker from a different brand install it and see what you think?  I'm sure the fact that all three identical Sierra 2's sound great is just a coincidence.   


Great, I've changed my mind.  I'm now going to sell my 5 timbre matching speakers (they all have the same exact tweeter and mid/woofer) and go out and find 5 speakers that really sound nice by themselves but not necessarily the same.  I'll place them where they look good and have a new idea for the industry.  I'm sure it will be all the rage and a very popular fad.

Don't forget to post your review/impressions of your new non-matching speaker system in the Lounge!

While I personally think you can't go wrong with making sure your speakers are all timbre matched (and the easiest way to do that is to just have them be all the same model), if someone else is happy with "mismatched" speakers then who am I to tell them otherwise? Whatever enables you to sleep peacefully at night is what I say.

My rears/side are matching, but not matching to front/center. Sounds fine. Also no way on earth would matching speakers fit (and I like diffused surrounds anyway)

[KeithL]

The situation is a little more complicated than it may at first seem.

First, as I mentioned in another post, most horizontal m-t-m arrays do NOT feed the same range of frequencies to both midrange drivers. The comb filter effect varies with frequency, and with distance, and occurs between EVERY driver carrying the same frequency. Therefore, if you have a left front, a right front, and a center, you have THREE "speakers", and interference between each possible pair/combination. And, if you instead use a pair of speakers, separated from each other, as your center, then you have interference between each two of those four speakers. Again, note that certain interference patterns may not be problematic, and some may even cancel out with others, but, the more speakers you have, the less certain your results will be. (So, using a pair of separated speakers for your center channel may work well, but there are going to be a LOT more variables to figure out, and a lot more combinations and permutations to consider.)

One thing I've always though might work well in some situations, but which I've never tried, would be to use two speakers for your "center", located at the sides of the screen, and then position them to "crossfire" - with each angled in at 45 degrees towards the center. This should give you the equivalent of a single center, with wide but controlled dispersion, and should serve to "pull" the image towards the center for listeners on either side. However, I would also expect it to reduce the overall width of the front sound stage slightly. (But, again, all of that will depend on the particular speakers and room you try it with.)

Mar 20, 2016 20:39:59 GMT -5 Boomzilla said:

OK... More data - I can put the twin bookshelf speakers (Infinity somethings) on the equipment stand with their tweeters but a couple of inches apart. That leaves the woofers spaced a couple of feet apart, but isn't that what big center-channel speakers do anyway? If that amount of spacing causes lobeing issues, then EVERY center channel on the market is flawed (per @bmoney 's claim). Now keeping in mind that the center is intended pretty much for DIALOGUE only, it seems to me that it wouldn't much matter whether a center MTM or a pair of closely spaced bookshelves was used. But, hey, I could be wrong...

And if closely spaced speakers are OK, then I'm not understanding why a pair of speakers (run in mono) three or four feet apart wouldn't be equally OK. Yes, it would provide only a "phantom" center image, but being no wider than the width of the couch (where we get friendly to watch movies), I'm not seeing where any loss would occur. Now the "phantom center image" from the main speakers, which are 12 or more feet apart, is fine for two or so centrally located viewers, but anyone not on the couch pretty much misses out on the dialogue.

I'm thinking that with the two "centers" being no wider than the couch, and with the partial reinforcement of the right and left "effects" channels, that the dialogue would be pretty clear. Since I'd like to have more equipment stand real-estate for the standard stuff (plus the occasional visiting component), putting the "center" speakers on stands is an attractive option, from a "make it fit" standpoint.

Now this speaks naught to the acoustical effectiveness of the rig. I may just have to try it & see. There are theoretical advantages and disadvantages, but pretty is as pretty does. Further, having the little Emotiva Fusion amp on the rack allows me to dynamically adjust the center volume via the remote - an option not currently available with the Fusion tucked behind the speakers on the rack with no clear path for the IR remote.

And as to matching, I stand by my comments on the "The Myth of the Center Speaker" thread. Timbre matching is where you find it - and not necessarily only from the same manufacturer. The little Infinities are slightly brighter than my main Axioms, but a felt in front of the tweeters should make them blend right in (until I find something better at the next yard sale)! LOL

Boom

[Boomzilla]

The two right and left speakers NEED to create a phantom center image to work in stereo. Despite room effects, one gets closer to a good phantom image by having the two speakers matched. The center speaker, however, needs not create any phantom image at all. Yet it is definitely best if the timbre matches the R&L so that pans from side to side don't create awareness of any acoustic discontinuities.

So I agree with both Yves and with Chuckie - It IS best if the speakers sound as alike as possible. Absolutely no argument.

But my experience matches yours, monkumonku - buying a center channel speaker from the same maker as the R&L speakers is absolutely no guarantee of anything like an acoustic match. For most people, this can be an insurmountable barrier - How are they to GET the match that they seek if the (manufacturer recommended) center is the off voice in the choir?

Fortunately, I can experiment with a wide variety of center channels from cheap to mid-range by scouring CraigsList and garage sales. I've used B&W, Axiom, Martin Logan, and Jamo in addition to Yamaha, JBL, Klipsch, and HTIB models. Sometimes, the best match is neither the expensive option nor the "same manufacturer" option. Acoustic harmony is where you find it.

[Boomzilla]

Mar 21, 2016 9:52:49 GMT -5 KeithL said:

Double Advents - now that's going back quite a ways.

Personally, I seem to recall the original Advents as having plenty of bass - and going pretty low pretty flat with their funny woofer. What they lacked was in the tweeter. The woofer was quite heavy, and so didn't extend very high, and the "orange peel" ring-plus-dome tweeter/midrange both didn't extend very high, and was a little weak in the lower midrange. This actually left them sounding quite neutral - except for a lack of very high end and a bit of a hole in the midrange. The Advents were sealed air suspension speakers, 8 ohms, and not especially efficient. So, by paralleling a pair of them, you ended up with 4 ohms, which coaxed more power from most solid state amplifiers, got more cone area for the bass (they were actually quite flat well into the low bass - but didn't have enough cone area to make huge amounts of low bass), and increased the efficiency a few dB. (Remember that, in order to double them, the top pair had to be placed upside down - so the tweeters were close together.)

To get the best effect, the grilles were kept "upright," despite the fact that the speakers were inverted to each other. The sound was flatter that way. (TRUTH)

Mar 21, 2016 9:52:49 GMT -5 KeithL said:

Advents and Klipsch speakers are about as far apart in sound as two speakers can get - and which you like is a matter of personal preference (I personally prefer the Advents).

Depends on the Klipsch... Some of the newer ones actually aren't far away from the Advents in tone.

Mar 21, 2016 9:52:49 GMT -5 KeithL said:

The main argument AGAINST using a pair of speakers for a center channel speaker is the comb filter effect. If you place two identical speakers side by side, and play the same signal through both, you get an interference pattern (called a comb filter effect). As you move your head from side to side the signal gets louder and quieter - in a pattern like the teeth of a comb. (The pattern varies with frequency, and with the distance between the speakers, but the "teeth" are between a few inches and about a foot apart - and can be quite noticeable if you move your head from side to side.) If you stack them vertically, then the pattern is vertical, so each frequency gets louder and softer as you move your head up and down. Most properly designed center speakers that use two midranges with a tweeter between them ("m-t-m pattern") actually don't feed the same signal to both midranges - rather they frequency-limit the signal to one midrange to reduce this effect.The real point is that any well-designed center speaker is going to take all of this into account, and simply putting two speakers side by side does not.

You are technically right, Mr. L - but EVERY SINGLE ONE of the center makers uses either a MTM or a TMT arrangement, thus ensuring comb filtering:

Mar 21, 2016 9:52:49 GMT -5 KeithL said:

It is almost always a good idea to have a center channel speaker that is matched to the front left and front right speakers. A different center channel speaker that has more midrange will make dialog that comes from the center more easily intelligible, but isn't going to work well for anything that's supposed to pan smoothly from side to side, or that's supposed to be located somewhere off-center in the front. Likewise, some speakers have similar vertical and horizontal dispersion patterns, and so can be placed either vertically or horizontally, some are designed specifically to be mounted one way or the other - and don't work well if you use them the other way. Another thing to keep in mind is that the horizontal and vertical dispersion you WANT from a speaker will depend on the room itself, and your speaker layout. For example, a center channel speaker with a wide horizontal dispersion will tend to give you a wider sweet spot, but, if your room is live, will tend to give you a less precise center location for dialog (more sound bouncing off the side walls). A center speaker with a narrow horizontal dispersion will give you a narrower sweet spot, but will tend to lock the image in more tightly to the center.

Agreed completely, BUT - "a center speaker that is matched to the front left and right speakers" is NEVER a foregone conclusion - even if you buy the recommended center from the same manufacturer.

Boom

[Boomzilla]

And if we're going by theory, the "BEST" center channel in the world is a point-source radiator. So a set of front KEF LS-50s is going to be hard to beat!

[novisnick]

A note, Paradigm IMHO has really nailed matching centers to their towers.

Just my two cents. 

[Deleted]

Mar 21, 2016 12:12:09 GMT -5 Boomzilla said:

The two right and left speakers NEED to create a phantom center image to work in stereo. Despite room effects, one gets closer to a good phantom image by having the two speakers matched. The center speaker, however, needs not create any phantom image at all. Yet it is definitely best if the timbre matches the R&L so that pans from side to side don't create awareness of any acoustic discontinuities.

So I agree with both Yves and with Chuckie - It IS best if the speakers sound as alike as possible. Absolutely no argument.

But my experience matches yours, monkumonku - buying a center channel speaker from the same maker as the R&L speakers is absolutely no guarantee of anything like an acoustic match. For most people, this can be an insurmountable barrier - How are they to GET the match that they seek if the (manufacturer recommended) center is the off voice in the choir?

Fortunately, I can experiment with a wide variety of center channels from cheap to mid-range by scouring CraigsList and garage sales. I've used B&W, Axiom, Martin Logan, and Jamo in addition to Yamaha, JBL, Klipsch, and HTIB models. Sometimes, the best match is neither the expensive option nor the "same manufacturer" option. Acoustic harmony is where you find it.

Not true. A center most certainly needs to create a phantom image between itself and the right. and itself and the left.

[goozoo]

I had a similar issue when building out my home theater.  I ended up placing speakers above and below the screen.  This in turn will create a ghosted center coming directly from the middle of the screen.  You can try other alternatives, but you will most likely come back to this setup.  

[Boomzilla]

Hi goozoo -

What a NEAT idea! Do you invert the top speaker? Bottom is tweeter up, top is tweeter down?

The "phantom image in the middle of the screen" is absolutely what the doctor ordered!

And a PS - I tried to grab a pair of KEF LS50s from the local CraigsList, but someone's already beat me to them. Oh well - maybe next time...

[yves]

Mar 21, 2016 3:46:55 GMT -5 @chuckienut said:

Mar 21, 2016 1:53:05 GMT -5 yves said:

Even if I decide to get an acoustically transparent projection screen and then place a center speaker behind it that not just timbre matches my stereo pair of speakers, but is IDENTICAL to them (as in, the EXACT SAME), the acoustic interaction that goes on between the stereo pair and the room is still going to be completely different than the acoustic interaction that goes on between the center speaker and the room. So unless you want to live in an anechoic chamber, whether you like it or not, nonsense does not exist.

Extending your logic then if you like many folks have a stereo pair only for music and the left speaker is significantly closer to the side wall than the right speaker then there is no reason to get a matched stereo pair of speakers, due to being completely different than the acoustic interaction of the other speaker in the pair (unless the room was perfectly equal in relation to the placement of the speakers)?  Perhaps above you are talking about the center being behind the screen while the L&R are front of the screen?  That is not the best idea but I would have the front of the center as close to touching the screen as possible and the rear of the L&R as close to the screen as possible.  As you know in a normal size room it is best to have the center speaker slightly behind the L&R so they are all equal distance.  That of course varies from room to room.

Your stating  "completely different" is a big exaggeration IMO.  If possible in your example above, the very best situation would be to have the exact same speaker in the exact same orientation.  We actually had a member here several years ago (don't remember if he is still active) who did just that.  He used three Emotiva ERM-6.3's, all were behind the screen all in the vertical orientation.  My recollection was he reported the sound was excellent.  Yes, if the center was the same distance from the wall behind and from the ceiling above but was farther from the side walls than the left and right speakers then there would perhaps be a very slight difference in sound.  However, that would seem to be as perfect as one could possibly get.  You seem to be suggesting that since the center speaker will never be the same distance to the side walls as the L&R then forget about getting a matched center speaker (to me that is nonsense).  Having a mismatched center as you seem to suggest would always make the situation worse.  Living in an anechoic chamber would be ideal but of course not possible.  However, we do make the room acoustics as perfect as possible in our room.  Dismissing having a timbre matched center speaker due to room issues is no excuse for not having the best matched center speaker possible.       

It's not such a big exaggeration after you have seen the measurements in REW or ARTA. There can be differences of up to 10 dB, and that is if you are a lucky guy.

P.S. - If you have a stereo pair only for music and the left speaker is significantly closer to the side wall than the right speaker then perhaps you should use headphones or listen in mono. J/K... my point was that a stereo pair is supposed to be symmetrical because so is the room setup, obviously, but between a front left speaker and a center speaker (or between a front right speaker and a center speaker) there can be no such symmetry, also obviously.

[goodfellas27]

DefTech CD8080 great center speaker

[copperpipe]

Mar 21, 2016 12:24:44 GMT -5 Boomzilla said:

And if we're going by theory, the "BEST" center channel in the world is a point-source radiator. So a set of front KEF LS-50s is going to be hard to beat!

Jokes aside; a 5/7 channel surround system using these exact Kef LS50's has been done, apparently sounds stunning. I believe it too, though might not be the best in very large rooms. I'm tempted to try something similar only using R300's


Edit; if you've never heard these LS50's, you owe it to yourself. Just do the "knock test", sounds and feels like you're hitting concrete. Very impressive speakers for the price.

[Bonzo]

www.magnepan.com/tri-center