Topic: using a pair of bookshelf as center speaker

[av_phile1]

.

Since you have done a short post, I guess I can respond with a short post as well.  

"Very long researched post."   That was actually a very short post. The article was long but I have had that in my mind for a long time because I thought that a lot of Pinoydvd members would appreciate it.

Frankly, I don't do that much research prior to posting here. I rely mainly on my personal experience because I will always hesitate to post based only on what I researched on the internet. I have tested 2 horizontally-oriented center speakers beside each other and on top of each other, as well as 2 vertically-oriented center speakers beside each other. I spent weeks listening to each set-up before trying another one. As @markcrenz has pointed out, the dialogue was not clear. Would you mind sharing with us your personal experiences?

I don't think it is a problem to disagree with anyone but I think that calling someone (like Chris Kyriakakis) a "joker" is impolite (and probably arrogant), especially if they are Ph.D.'s who have many years of dedicated professional work of experiments on acoustics and psychoacoustics. Would you mind telling us your own qualifications, both academically and professionally?

Now, with regard to Audyssey, would you mind talking to us about your personal experience with Audyssey? I suppose you have tried Audyssey MultEQ? Have you tried the different flavors of MultEQ (2EQ, MultEQ, MultEQ XT, Audyssey Pro, Sound Equalizer, the SVS AS-EQ1)? Have you tried Audyssey Dynamic EQ or Dynamic Volume? Can you please explain to us why you have a low opinion about these products, presumably after you actually listened to all these?

And may I suggest ... can we be civil in our posts? This is just a hobby.  

I am not swayed by mere credentials, When I see a statement like comb filtering as "about the worst possible thing you could do to mess up the sound." it doesn't speak well of their credentials.  It is very clear they're just trying to impress with things that don't matter just so they they can sound learned and impress people who are not.  If that doesn't make them jokers to you, you're free to defend them.

Impolite?  My goodness, It was you who impugned my statements as if you had the monopoly of the right answers just because you had some so called gurus on your side,  Like who am I to challenge a PhD holder and a foreigner at that.

I really couldn't care less if you take their statements hook line and stinker  That's your prerogative. I've already made my position clear.  You like THX and MultiEQ?  Good for you,  I don't.  Like you said this is just a hobby.,


  

[macdon]

@macdon,
i already bought the pylox but my impulse/urge to have it painted black slowly faded. it does not look an eye sore anymore after getting used to it. if only i live near diymaster, i will have it vinyled by him immediately.

Good for you brader Weng - if it aint broke, better not mess with it

As for the Pylox - its actually an inside joke among friends here in pdvd with regards to how we can maintain a match finish with our B&W speakers since the outgoing series3 were dwindling in numbers 

.......but i never thought somebody would take me seriously

Have you considered ordering your preferred vinyl color thru Anthony and just asking him for a tutorial on how to do it? I bet you can do it - nothing ventured, nothing gained

[Stagea]

I'd like to raise the point that most center speakers only have one tweeter (or one tweeter and one small midrange driver). Tweeters are fairly efficient, and a solitary one is usually still more sensitive and more efficient at its working frequency range versus two woofers working in tandem. Given this fact and granted that the tweet can play loud enough to keep up with the other drivers at full tilt, then this would be a win-win scenario.

This is because having no duplication of the high frequency drivers saves cost, and minimizes the phase issues in higher frequencies (thus lessening the comb filtering effect when listening from an off-axis position). This should effectively widen the usable dispersion of the speaker.

what would be the difference between the 2 electronically, sonically and etc.

1. a center speaker with 2-ea 6.5 drivers and 2 tweets in the middle

vs

2. 2 BS speakers with a single 6.5 driver and a tweet placed side by side horizontally with the tweets in the middle

[streetsmart]

When I see a statement like comb filtering as "about the worst possible thing you could do to mess up the sound." it doesn't speak well of their credentials.

I suggest you read posts more carefully because that's not what he said:

Running two center channel speakers is about the worst possible thing one can do to mess up the sound.

In other words, he seems to be saying that when you run 2 center channel speakers, the comb filtering is  severe and will seriously affect sound quality. He never said that comb filtering per se is the worst possible thing in audio.

[av_phile1]

The cause effect relationship is there.   I just did a short cut to my statement.  If you noticed the words comb filtering were not part of the quotation.  

[streetsmart]

The cause effect relationship is there.   I just did a short cut to my statement.  If you noticed the words comb filtering were not part of the quotation.  

I'm sorry but what you are saying is illogical. In Mathematics, this would be called "set theory."

The correct logic is as follows:
Comb filtering is a common phenomenon.
If you have 2 center speakers, it is aggravated.
Ergo, it is not advisable to have 2 center speakers.

[markcrenz]

I fully agree with this statement and I don't think it has been answered. My personal actual experience is exactly the same as yours -- a single upright center is much better than a pair that is horizontal or a pair that is vertical and side by side.

I've never tried 2 speakers, one on top of each other. My guess is that it will be okay.

Tukayong Mark, why don't we just ignore the results of our experiments and forget about what Prof. Chris Kyriakakis told you? Now you can use your other stratus tower and place it horizontally, side-by-side or beside both fronts. It doesn't matter after all! 

[streetsmart]

Tukayong Mark, why don't we just ignore the results of our experiments and forget about what Prof. Chris Kyriakakis told you? Now you can use your other stratus tower and place it horizontally, side-by-side or beside both fronts. It doesn't matter after all! 

Hehe.  I followed the advice of Chris to have just one center speaker and immediately noticed the improvement in intelligibility of the dialogue. So yes, I have verified that it does matter. 

When I said "one on top of the other," I meant vertically. E di more than 6 feet na yun kasi nga tower ang center ko, kaya nga impractical. Baka pwede kung bookshelves lang but I'm still concerned about the fact that there would be 2 tweeters and woofers outputting the same signal, with slightly different distances from your ears. My understanding is that's the condition for serious comb filtering.

[Weng!]

Hehe.  I followed the advice of Chris to have just one center speaker and immediately noticed the improvement in intelligibility of the dialogue. So yes, I have verified that it does matter. 

When I said "one on top of the other," I meant vertically. E di more than 6 feet na yun kasi nga tower ang center ko, kaya nga impractical. Baka pwede kung bookshelves lang but I'm still concerned about the fact that there would be 2 tweeters and woofers outputting the same signal, with slightly different distances from your ears. My understanding is that's the condition for serious comb filtering.

sir mark (streetsmart),

what would be the difference of the 2 woofers and tweets placed horizontally versus a center speaker with 2 woofers and 2 tweets (in the middle) if both are powered with the center channel?

i did several tests with one speaker and 2 speakers placed horizontally and i could not point out the difference. loudness is the same using 2 speakers and this could be due to only half the amp output powers the 2 speakers.

[dips15]

sir mark (streetsmart),

what would be the difference of the 2 woofers and tweets placed horizontally versus a center speaker with 2 woofers and 2 tweets (in the middle) if both are powered with the center channel?

i did several tests with one speaker and 2 speakers placed horizontally and i could not point out the difference. loudness is the same using 2 speakers and this could be due to only half the amp output powers the 2 speakers.

Just wondering though.  If the volume is still the same, why would it be better to have 2 speakers?

Am also contemplating using a pair of bookshelves but they are just huge.  Even without stands, they are around 22 inches with 8 inch woofers. 

Am I correct in saying that if the volume is good enough then you don't need to add the 2nd speaker?

[Weng!]

Just wondering though.  If the volume is still the same, why would it be better to have 2 speakers?

Am I correct in saying that if the volume is good enough then you don't need to add the 2nd speaker?

you are right but what will i do with the other speaker and stand if i only use one? both speakers sits comfortably already in front so i may just leave them as is.

[streetsmart]

sir mark (streetsmart),

what would be the difference of the 2 woofers and tweets placed horizontally versus a center speaker with 2 woofers and 2 tweets (in the middle) if both are powered with the center channel?

i did several tests with one speaker and 2 speakers placed horizontally and i could not point out the difference. loudness is the same using 2 speakers and this could be due to only half the amp output powers the 2 speakers.

I don’t espouse myself to be a guru but my personal opinion is as follows:

Center speakers with 2 tweeters have the tweeters typically vertically-aligned and quite close to each other. The smaller the distance between the tweeters, the higher the frequency (and therefore less audible) is the effect of comb filtering. My understanding is also that a vertical alignment of drivers is always superior to horizontal. In fact, you have speaker designs of more than 10 identical drivers, but they are all vertically aligned.

On the other hand, If you lay the speakers beside each other, the tweeters will be horizontally aligned and farther, therefore affecting lower and more audible frequencies + the horizontal design will definitely induce comb filtering. It is the combination of the small distance between the drivers and the horizontal configuration with the same signal that produces the comb filtering.

A center speaker with 2 woofers flanking a tweeter will always have comb filtering. My personal take is that the manufacturers produce these because they easily fit below the TV, even if they are inferior to a vertical design. Perhaps, the manufacturers have a trick to reduce comb filtering? I don’t know. But definitely, if you have 2 speakers, they will not be designed to act as 2 center speakers and will have no compensation for comb filtering.

The loudness can easily be adjusted. The difference should be in the uneven frequency response - certain frequencies in phase, others out of phase. You should hear it in unclear dialogue or a smearing of musical instruments in multi-channel concerts.

Again, this is my personal take on the reasoning behind this. If you don’t notice any difference, then don’t worry about it – honestly. 

[streetsmart]

you are right but what will i do with the other speaker and stand if i only use one? both speakers sits comfortably already in front so i may just leave them as is.

I have the same problem. I have an extra tower speaker. Suggestion - use the extra speaker as a single rear channel.

If one speaker can handle the center, just use one.

[markcrenz]

i did several tests with one speaker and 2 speakers placed horizontally and i could not point out the difference.

add ko lang if i may... try the test while you're seated at the extreme left or right of your listening area - these off-axis locations show most improvement. i did my listening tests both on- and off-axis. but...

If you don’t notice any difference, then don’t worry about it – honestly.  

Just wondering though.  If the volume is still the same, why would it be better to have 2 speakers?

i'm not saying that it would be better, but with the two speakers in series, your amp is working at only about half the power than if it were driving only one. that means your amp will run cooler, with less distortion and probably serve you longer; with some savings on electricity to boot! you will be able to achieve higher sound levels before your amp clips.

[Weng!]

I have the same problem. I have an extra tower speaker. Suggestion - use the extra speaker as a single rear channel.

If one speaker can handle the center, just use one.

i am using an evo8's for the rear and dfs sa surrounds, wala na talagang paglayan. 2 na ang maging out of use na speakers ko, ang evo center at ang evo10 kung isang center lang gamitin.

[dips15]

If it sounds at least the same to you and you don't have any other place to use them and it doesn't do any damage and maybe lessens the load of your AVR, then might as well keep using both.

[av_phile1]

I'm sorry but what you are saying is illogical. In Mathematics, this would be called "set theory."

The correct logic is as follows:
Comb filtering is a common phenomenon.
If you have 2 center speakers, it is aggravated.
Ergo, it is not advisable to have 2 center speakers.

You demonstrated my logic perfectly, If you have 2 center speakers, comb filtering is aggravated.
therefore, it is not advisable to have 2 center speakers. That's tantamount to saying that (aggravating) comb filtering is the worst possible thing to can do to mess up the sound.  Rather than saying putting two speakers together would.  Like I said I short cut the statement.  Admittedly. the word aggravating would have made the statement more accurate.

But again, it doesn't matter.  because you only aggravate the mathematics,  not a perceptible acoustic situation that matters in your sweet spot.  That's because your room is so full of acoustic phase shifts reaching your ears that putting two identical speakers in the same channel could not acoustically aggravate it even if you wanted to on the same preferred listening position.    People who insists that comb filtering matters a lot should try and relate their presumably profound technical intellection with the real world psychology of sound perception by the ears and its cognitive interpretation by the human brain.    Not all mathematics have that kind of real world significance to lose sleep over or be bothered about.  At least not in a typical room.  But anyone is free to consider the mathematics in his choices.  I am just saying it is not the worst thing anyone can do to mess the sound.

[av_phile1]

you are right but what will i do with the other speaker and stand if i only use one? both speakers sits comfortably already in front so i may just leave them as is.

Your two speakers sitting in front for center are just fine. If you can hear any difference with a single one, then just choose which one you like.  This is not the first time that two speakers are being used for center channel.  The halving of power requirement by doubling your impedance can be good to your amp.  The SPL levels would be the same anyway especially at close proximity.  

[TinkerTailor]

all this talk about about comb filtering made me curious enough to consult mr google. one of the first to pop up was this:

http://forum.ecoustics.com/bbs/messages/34579/572305.html

now i understand a little why some say that comb filtering is not your worst enemy in this here persnickety thing that we call audio or ht hobby

[dips15]

On a related note, I am planning to use relatively tall bookshelves which stand at 22" height.  I will place them vertically to correspond with its natural orientation. 

As tall as it is, I don't think it would be necessary to place it on a stand.  Instead, I am thinking of using spikes for it to stand properly.  If I decide to do so, should I angle the bookshelves a little upwards by placing spikes only on the front of the speakers and leaving the back to stand up on its own or is its still better to have the speaker leveled equally?

Any advice would be appreciated.

Thanks.

[av_phile1]

On a related note, I am planning to use relatively tall bookshelves which stand at 22" height.  I will place them vertically to correspond with its natural orientation.  

As tall as it is, I don't think it would be necessary to place it on a stand.  Instead, I am thinking of using spikes for it to stand properly.  If I decide to do so, should I angle the bookshelves a little upwards by placing spikes only on the front of the speakers and leaving the back to stand up on its own or is its still better to have the speaker leveled equally?

Any advice would be appreciated.

Thanks.

No problem, provided the angling will result in the center speaker's tweeter aligning with those of the L and R when it reaches your ears at your listening position.

It's ideal and often the rule to have the tweeters of your LCR speakers align along an imaginary horizontal line connecting them, plus or minus an inch.  The tweets of your LCR speakers should be level with your ears when you are seated at your listening position.   Angling a center speaker from the floor or from a height so that its tweeter sound reaches your ears at the same horizontal plane as those from your L and R is a common practice.

[Weng!]

add ko lang if i may... try the test while you're seated at the extreme left or right of your listening area - these off-axis locations show most improvement. i did my listening tests both on- and off-axis. but...i'm not saying that it would be better

update: last night i watched a full movie while fiddling with the center speakers several times. my wife was already irritated watching me pausing the movie a lot of times to unplug wires back and forths this time i was seated on the extreme right and noticed that using 2 speakers the sound became compressed or out of phase (dunno if this is the right term). but with only one speaker the sound was more fuller and open. also, placing the speaker upright made it even better.

i will run another test using the evo center to compare with the single evo10 bookshelf just to convince myself that i am doing the right thing to ditch the evo center for good.

[seymorebutts]

makikisali na rin kasi na-curious ako

center ko ay wh2, ok naman sya, entry level, tapos pinalitan ko ng mission mv2, mas fuller nga sya at louder at nagkaroon ng bass yung dialogue. hindi ko pa na try yung 2 center.......

[streetsmart]

update: last night i watched a full movie while fiddling with the center speakers several times. my wife was already irritated watching me pausing the movie a lot of times to unplug wires back and forths this time i was seated on the extreme right and noticed that using 2 speakers the sound became compressed or out of phase (dunno if this is the right term). but with only one speaker the sound was more fuller and open. also, placing the speaker upright made it even better.

i will run another test using the evo center to compare with the single evo10 bookshelf just to convince myself that i am doing the right thing to ditch the evo center for good.

That's the right thing to do. You need to experiment, even if it annoys your wife! 

Good luck! 

[mike c]

perfect actually ang triple vertical speakers in front.

horizontally placed speakers have compromised left to right performance.

[markcrenz]

That's the right thing to do. You need to experiment, even if it annoys your wife!  

Good luck! 

correct! sila rin naman makikinabang dahil kadalasan they sit at the sides. atin syempre ang sweetest spot!   

[streetsmart]

correct! sila rin naman makikinabang dahil kadalasan they sit at the sides. atin syempre ang sweetest spot!   

Hahaha! Korekek!!! 

[iiinas]

correct! sila rin naman makikinabang dahil kadalasan they sit at the sides. atin syempre ang sweetest spot!   

Hahaha! Korekek!!! 

come think of it, 100% agree ako dito. hehe.

[jerix]

Just want to add this. I hope we can benefit something from this article.
http://forum.blu-ray.com/speakers/89614-horizontal-center-channel-speakers-why-they-should-avoided.html

[praktikal]

correct! sila rin naman makikinabang dahil kadalasan they sit at the sides. atin syempre ang sweetest spot!   

palagay ko, ako lang ang sasalungat dito 

kapag may kasama ako, lagi ako sa tabi para mas enjoy s'ya/sila