Unwritten rule that all speakers can't be the same?

[nick_danger]

It seems like everyone is so quick to use only "main" speakers for the front channels, "surround" speakers for the surrounds and a "center" speaker for the center. I can understand having a sub-woofer for LFE, that's just a given - and center channels should be optimised for voices and such, but for the remaining speakers, would it "go against the grain" to have them all be full-range floor-standing speakers?

Not all content sends full frequency to the rears or surrounds, but wouldn't it be worth it to match the front channels just in case?

I'm thinking of buying five Yamaha NS-777s from eTronics (on sale, with shipping for $194 each) for my mains, surrounds, and rear. Am I being wasteful with this?

 

[Rip Van Woofer]

Wasteful? Not at all. (OK, maybe a bit exravagant, but that's part of the fun in this hobby!) Those "large" settings for the surrounds on your receiver or prepro are there for a reason, after all. If you can get good full-ranges all around within your budget, it's great! Especially for pop recordings where instruments are mixed discretly in all channels for that "middle of the band" effect. And having most of the bass handled by multiple speakers around the room might help cancel or ameliorate room modes and boundary effects that make for uneven, "peaky" bass. Just add a good sub for the very lowest octave or so and enjoy, you lucky devil you!

 

[nick_danger]

Awesome. OK, it just seems that everyone is so caught up in having specific speakers for each channel and I couldn't see a really great reason why. I'd rather have symmetry in the appearance and output, anyway. Yeah, I'll eventually get a really low-hitting sub, but is there a receiver that will let me send LFE to all the speakers or that will balance it or time it to avoid the problem you mentioned?

 

[MJC]

By all means use all the same speakers. All seven of my speakers are the same. The only difference is that my main L/R are mirror imaged and the rest have the drivers on the center of the baffles. And I'm not talking small speakers either. They're 3 way, 25" tall, not counting the bases. The sides and back surrounds are mounted on the walls, and the 3 front speakers are floor standing.

 

[Rob Babcock]

All identical speakers is the best possible way to go, especially for MC music. Most people go with dedicated surrounds and center for aethetic reasons and for budgetary concerns. The main hurdle most people face when trying to go with all identical speakers is that it's tough to site a tower as your center; in most rigs it blocks the tv. Another problem is that whether you have a 5.1 or a 7.1 system, mains are generally sold in pairs, meaning you have to buy one more speaker than you actually need. 6.1 has no such drawback, of course.

 

[plhart]

I'll have to ask Clint, our esteemed Editor-in-Chief to see if we can highlight a bit better this url to the Recording Academy's "Recommendations for Surround Sound Reproduction">>

http://www.grammy.com/pe_wing/guidelines/index.aspx

These recommendations by the Recording Academy came out a only a few weeks ago after three years of work from a distinguished committee of many of the pre-eminent multi-channel recording engineers in the world. I covered the "launch" of the recommendations which took place during a seminar on Day 2 of the EMX conference in Hollywood held one week before CEDIA. (Found under Trade Shows on our site.)

In presenting the recommendations, the Recording Academy committee members stressed that member's had fought vigorously among each other on many, many points but they felt that after three years it was best to get a document published which could serve as a reference for discussion and subject to eventual modification or amendment.

To your point at hand. Among the "Summary of Recommendations" which serves as a sort of Table of Contents for the document the ninth bullet point reads "Surround mixing should always be done on identical full range speakers of the same brand and model, plus a subwoofer."

Note that Recording Academy engineers are from the audio-only portion of the recording industry which means they mix for recording artists primarily, not movies. They have been the pre-eminent mixers of stereo recordings for decades and they are still having a ball experimenting with this relatively new surround sound media.

Before everyone reads the bold sentence about five identical full range speakers and concludes that that statement is a blanket OK I'd recommend a though read-thru of the document to understand all the parameters recommended in the five speaker ,full-range set-up. What you'll find are strongly recommended room treatment and "no sweet spot" criteria which will probably not be followed in a home environment.

Think room modes run amok! Five "full range" woofers, all generating room modes from their own locations. Big problems that are hard to control.

The drawbacks to the "five full-range systems" format will be covered in Part 5 of The CEDIA Seminars which was taught by Dr. Floyd Toole. The bottom line though is that to reproduce five (or seven channels) plus subwoofer information in the home, in a level-matched, accurate way we must be able to control to the greatest extend possible the room acoustics. The room modes potentially set up by five full range speakers require complex and costly solutions.

 

[Rob Babcock]

Bear in mind that using 5 identical speakers in no way dictates that they be run full range. You can still set them all to "SMALL" and allow the proc to offload the bass to a sub.

 

[plhart]

Bear in mind that using 5 identical speakers in no way dictates that they be run full range. You can still set them all to "SMALL" and allow the proc to offload the bass to a sub.

Sorta defeats the purpose of a big floor stander though. A well-designed 4" two-way can get down to the 80Hz -3dB point. The problem then becomes proper speaker positioning within the room.

 

[Rob Babcock]

I didn't realize we were talking about "big" floorstanders, or only floorstanders, for that matter. Mine are 6.5" two ways. They have decent bass, but nothing like my pair of Hsu TN1220s. Very few speakers produce that kind of bass. You can probably name every good sounding speaker that's flat to 20hz on one hand (at least every one under $5k).

I only used the word "towers" once, and then merely as an example of one possible situation. You could just as easily use 5/6 bookshelfs, too. Identical speakers need not mean floorstanders. My main point is that the only way to guarentee identical voicing is to use identical speakers! I'm sure you're aware that oftimes models that are said to be "voice matched" aren't really voiced that closely at all.

As for 4-inchers flat to 80hz, well- how many speakers can you think of with that small a "woofer" that didn't suffer from a hole in the bass or severe dynamic compression? Sure, specialty drivers like the Tang Band 4" have a higher excursion than most, but the majority of 4" consumers speakers are underacheivers. But that said, no one says you can't use 5 or 6 identical speakers with 4" drivers, either.

 

[Leprkon]

The main reason for having "dedicated" surround speakers is convenience. Some people don't want to have cables on the floor going back to a floorstanding (or even stand-mounted) speaker to get the action behind them. The stuff just gets in the way, even when it's right behind the sofa. Since the rear speakers are mainly for motion effects, small, light, ceiling and wall-mounted speakers with in-wall wiring have their own market.

You'd think that the best system would be identical all the way around, but it's usually the common sense of decor (or WAF) that limits the size of the surrounds.

Somewhere down the road, and I'm sure this is George L's wet dream, the movies will be mixed such that stuff happens with you in the very middle of the action which would require every speaker to be identical. For now, we can get away with smaller rears.

 

[Rob Babcock]

Exactly what I've been saying, Leprkon- it's often WAF, budget & other mundane issues that dictate compromises. Bear in mind though that the original question was "can you use identical speakers?" And of course you not only can do so, but you should do so if you don't have any other limitations imposed upon you.

 

[Leprkon]

Exactly what I've been saying, Leprkon- it's often WAF, budget & other mundane issues that dictate compromises. Bear in mind though that the original question was "can you use identical speakers?" And of course you not only can do so, but you should do so if you don't have any other limitations imposed upon you.

dang... it only took him 1,000 posts to agree with me......

 

[Rob Babcock]

So what about my 950 posts before you showed up?

 

[Karp]

Awesome. OK, it just seems that everyone is so caught up in having specific speakers for each channel and I couldn't see a really great reason why. I'd rather have symmetry in the appearance and output, anyway. Yeah, I'll eventually get a really low-hitting sub, but is there a receiver that will let me send LFE to all the speakers or that will balance it or time it to avoid the problem you mentioned?

Most receivers will do this. Just set all of your speakers to large and your subwoofer to none. The LFE will be sent to the respective channels.

If you set all speakers except the fronts to small, then your fronts will receive the LFE.

 

[WmAx]

Exactly what I've been saying, Leprkon- it's often WAF, budget & other mundane issues that dictate compromises. Bear in mind though that the original question was "can you use identical speakers?" And of course you not only can do so, but you should do so if you don't have any other limitations imposed upon you.

Actually, true full range bass response placed at every position will [1]cause undesirable response anomolies. It is desirable to use corner loaded subwoofer(s) for the greatest linearity.

-Chris

Footnotes:
[1] Multiple Subwoofers for Home Theater
Nousaine, Tom
AES Preprint: 4558

 

[Rob Babcock]

Floyd Toole's most recent research indicates multiple subs pulled well out of the corners is far superior to corner loading. The "old school" view has always been to stick your sub in the corner to get the biggest boost from the trihedral corners, but Tool's data says this isn't the most linear way to load a room.

I'll agree that running the mains all full range may not be optimal, but oddly enough that's been Sony's recommendation with regards to SACD, and they're not the only manufacturer to do so.

Any at rate, bear in mind that using 5 identical speakers and running all 5 of them full range are two completely separate issues. The identical speakers need not be set to "LARGE" nor produce very low bass.

 

[b_panther_g]

When dealing with full-range speakers all around, has anyone actually tested how much bass cancellation occurs?

I’m not sure, but wouldn’t cancellations/reinforcements be most noticeable if mono bass were coming from multiple places at the same time? In non-mono recordings, wouldn’t there be different sounds coming from each speaker?

Some more info about this would be helpful.

Thanks,
B

 

[WmAx]

Floyd Toole's most recent research indicates multiple subs pulled well out of the corners is far superior to corner loading...

I'll agree that running the mains all full range may not be optimal, but oddly enough that's been Sony's recommendation with regards to SACD, and they're not the only manufacturer to do so.

Any at rate, bear in mind that using 5 identical speakers and running all 5 of them full range are two completely separate issues. The identical speakers need not be set to "LARGE" nor produce very low bass.

I was addressing the issue of placing full range speakers operating at full range bandwidth at standard main + surround positions simultaneously -- in response to the user I replied. I did not intend to address 'any' possible configuration of multiple subwoofers, if that is what you inferred.

While it is true that a large number of subwoofers can [1]potentially even out response, the positioning resulting in this effect is [1][2]unlikely to occur at the standard combination of coincidences of the main left, right and left, right rear surround positions. I am not aware of a Toole study on this particular issue. However, Todd Welti(Harmon Kardon) has published work on this issue that supported Tom Nousaine's conclusion. Nousaine's papaer also analysed the response at the standard main + surround positions. The results for both researchers was the same for this placement combination in an average calculated rectangular room: significant deviations compared to other possible configuration(s).

-Chris

Footnotes:
[1]How Many Subwoofers are Enough?
Welti, Todd
AES Preprint: 5602

[2]Multiple Subwoofers for Home Theater
Nousaine, Tom
AES Preprint: 4558

 

[plhart]

May the circle be broken...Part 1

Gene suggested that I might want to get re-involved with this discussion so here goes>>

1. Unwritten rule that all speakers can't be the same?

The title of the original query posted by Nick Danger. (We luv ya Nick! Yes I do have most all original LP copies of the Firesign Theater)

1. ..."go against the grain" to have them all be full-range floor-standing speakers?

The essence of Mr. Danger's question. What Nick does not specify here is whether or not we're talking about an audio-only (no movie watching) home theater system, or a combination audio-only/ movie system.

Systems to reproduce both formats in the home began with 3-channel Dolby Surround in the mid eighties. Two channel "anything" worked okay over the 3 channels, VHS tape, CDs, even LPs.

Then came 4-channel Dolby Pro Logic ('89) with a center channel and the audio-only 2-channel sources didn't work for beans whereas the encoded VHS tapes opened a whole new world of movie surround enthusiasts. Big mains, small surround with small amps driving them were the norm.

Now we come to discrete surround in the form of Dolby Digital and DTS ('95). A movie format. And way back in the eighties Tom Holman with Lucasfilm, working with Dolby, had figured out not only the movie theater surround format but he'd also proposed 5.1 for the home which was meant to be compatible with the theater soundtrack.

The essence of Tom's proposal was left-center-right channels which would follow the action and dialogue in the front part of system, effectively tying the audio directly to the on-screen video.

In the rear, dipoles were specified specifically because dipoles DO NOT inherently give away their position. Rather, dipoles are specified to add a feeling of IMMERSION and ENVELOPMENT to complement what is happening on the screen. This allows, for instance, the inclusion of a beautifully integrated orchestral soundtrack on a movie such as "Shakespeare In Love" to be produced and appear to float in the rear channels while at the same time complementing the dialogue on the screen.

Note also at this time ('95) that SACD and DVD-Audio did not exist. They were only proposals. What did exist of course where 5.1 systems with matched monopolar speakers all around. In most cases the 5 monopole 5.1 systems existed because it was much easier and cheaper to make a "surround" speaker which didn't have to have so many drivers. It does after all seem counterintuitive to have to pay more for a speaker one will supposedly hear less of. "But damn, if I'm going to pay for this 5.1 system in the first place I want to hear and locate the source of that surround effect." So say many home theater enthusiasts. Wrong...

The fact is that Tom Holman's research was essentially correct. His 5.1 small satellites with sub(s) can satisfy both movies and discrete audio surround. It just a matter of proper implementation of correct speaker configurations along with the type of attention to your home theater that is given to THX certified theaters. Did you know THX has now come out with a Home Theater (not equipment) certification program.

2. If you can get good full-ranges all around within your budget, it's great! Especially for pop recordings where instruments are mixed discretly in all channels for that "middle of the band" effect. And having most of the bass handled by multiple speakers around the room might help cancel or ameliorate room modes and boundary effects that make for uneven, "peaky" bass. Just add a good sub for the very lowest octave or so and enjoy, you lucky devil you!

Sure multiple full range speakers might help ameliorate ...."peaky" bass. What we don't ever know with such a statement is how much amerlioration? And will that be good enough? What tolerances are "good enough"?

We would prefer to come from a place or with a methodology or product which can actually address the room modes. Would we not?

Harman will be announcing a product which can EQ any amount of subs starting with two and going up in single units. Dr. Toole talked about this product which will be proprietary to the high-end Synthesis theater system during his seminar at CEDIA. He did, however, vehemently disagree with the Recording Academy engineer's recommendations regarding 5 full range speakers when I handed him the first copy of the Recommendations he had seen. This was during a break in the fifth CEDIA seminar taught by Floyd last month.


3. All identical speakers is the best possible way to go, especially for MC music.

ONLY for MC music. As explained above. "Identical" means the rears are monopoles. To get an approximation of "envelopment" for movies; in other words, to hear what the engineer heard and the director intended in the movie mixing soundstage, try shooting the monopoles backwards into a diffusor.


4. I didn't realize we were talking about "big" floorstanders, or only floorstanders, for that matter.

Yep, that was the first thread.

5. As for 4-inchers flat to 80hz, well- how many speakers can you think of with that small a "woofer" that didn't suffer from a hole in the bass or severe dynamic compression?

Changing the subject regarding a 4"ers potential to one of "do they exist" and/or "if they do they must not be able to play very loud". The answer is yes, they do exist. The Infinity Beta HCS system sold only in Europe. It's + or -1.5 dB 90-20KHz and -3dB at 80Hz. The three fronts can sustain over 95dB continuous. That's really loud. Compression for a single unit is at about 98dB. There's also a self powered NHT with a 4.5" which is very nice.


6. The main reason for having "dedicated" surround speakers is convenience

Incorrect, if you're talking about 5.1 movie soundtracks. Dedicated surround speakers are meant to give a sense of envelopment.

 

[plhart]

May the circle be broken...Part 2

7. Bear in mind though that the original question was "can you use identical speakers?"

Incorrect, see answer to #1 above.

8. Floyd Toole's most recent research indicates multiple subs pulled well out of the corners is far superior to corner loading.

Incorrect. Multiple subs pulled well out of the corners lose a potential of 6dB of "free" gain which you get when you move into a corner. What those subs pulled out from the corners DO gain is the Potential to exhibit less peaky response in any one given frequency or frequencies eqif no means of equalization are available.

The corner mounted subs on the other hand have much More Potential to excite a single peaky response which is dealt with using single band parametric EQs like Infinity's RABOS. Dr Toole, in his seminar showed several configurations of multiple woofers; all four corners, two front, two rear, along their respeactive walls, even four subs out into the room and firing from the ceiling.

The point is, what Floyd's research department has found is that once you've got a system which can equalize 2,3,4, 5 subs all at once in a room, using a single band of equalization on each, you've pretty much got the problem licked. As Long As They're Subs!

9. I'll agree that running the mains all full range may not be optimal, but oddly enough that's been Sony's recommendation with regards to SACD, and they're not the only manufacturer to do so.

Well sure. Sony has pushed SACD for years. To them it is a separate issue from watching movies. Remember, back when SACD and DVD-Audio were still being discussed as to who would be the standard, the buff mags at the time were saying that to do it right you needed a dedicated audio system in one room and a dedicated video system in the other. Hard to believe, looking back. Now Sony appears to be backing off of SACD altogether and they never have been a presense in loudspeakers, so what do they care?

10. When dealing with full-range speakers all around, has anyone actually tested how much bass cancellation occurs?

This is an impossible question to answer. Every room/speaker combination will be different. Note the Recording Engineers recommend that all five full range speakers be the same distance from the mixing position but within a range of only 6.5 to 7.5 feet! Think these guys haven't figured out what a problem this arrangement already is?


10. I’m not sure, but wouldn’t cancellations/reinforcements be most noticeable if mono bass were coming from multiple places at the same time? In non-mono recordings, wouldn’t there be different sounds coming from each speaker?

Cancellations/reinforcements would be noticeable with mono bass If the sub is not properly positioned so that a bass peak exists. But, if the sub is properly positioned so that the sub has a linear response across its frequency range than no frequency will stand out from another. This can also be accomplished by putting a sub where you want it and using a 1/12 or 1/20 octave parametric EQ to attenuate the single frequency peak that most commonly exists.

In the case of "full-range speakers" playing "non-mono", non-encoded recordings, yes, you would get different bass notes coming out of each speaker. The question then becomes how low in frequency is the note, where is your listening position , and does that frequency create a room mode right where you are?

11. I was addressing the issue of placing full range speakers operating at full range bandwidth at standard main + surround positions simultaneously

See #10 above re: the Recording Academy recommedations. And read all of the document. Because some points seem to contradict others.

11. While it is true that a large number of subwoofers can [1]potentially even out response, the positioning resulting in this effect is [1][2]unlikely to occur at the standard combination of coincidences of the main left, right and left, right rear surround positions. I am not aware of a Toole study on this particular issue.

Absolutely correct. This is the point Floyd makes in his CEDIA seminar. We never, ever deal with a perfectly rectanglar box for a room. Once a door or window is put in the room the computer simulation (for a perfect room) is worthless. This again is the reason that Floyd and his guys have developed the multiple subwoofer computer equalization program. One band of parametric equalization per sub is all they're using at present. With that he's shown a slide which gets his four subs in his personal living room/home theater within + or - 3dB anywhere in the room. He says the effect is eerie. And indicates that before this system gets into production they may get a tighter performance window out of it.