Difference between HT and Music speakers

[servicetech]

What are the main differences in the design of speakers for Music vs. HT ?

[looneybomber]

IMO, nothing. What should be good at one, should also be good at the other. I see no reason why someone should need one set of speakers for this and a different set for that. I could see how one speaker might be OK for HT, but not ok for music, but that's because HT is much less critical than music, so design flaws are more acceptable. But again, I said OK for HT, not good. Any good speaker will be good for either.

[servicetech]

That's what I was thinking, however I see posts here that stating how the speaker will be used when posting a design question. My current L/R speakers sound great for HT but are a little lacking for music.

[tpremo55]

The role of the speaker is the same, the material is often slightly different. When listening to a speaker with good musical characteristics, I like to listen for soundstage, the way the speaker reproduces the human voice, the squeek of a finger drawn across a metal guitar string, and the speed and accuracy of a small bell or triangle and often the depth of the base material in the recording. With HT, Dynamics across the entire range becomes a key factor. The ability for a speaker to go from the quiet of footsteps to an explosion right in front of the viewer without straining.

There are some great designs on this forum that come really close to doing both equally well, however I would submit that a real HT experiece would necessitate a subwoofer whereas music is very well reproduced with a number of the posted designs.

Todd

[kevmurray]

I'd agree that a good speaker should do it all, but in the real world compromise is inevitable. Six or more speakers get expensive so premium parts are usually out of the question. Not that explosions and screeching tires need them anyway. I wish I were rich... (sigh)
I can share a recent experience. I'm currently designing my idea of a great HT setup and have run into a nice little problem. I'm tri-amping with active crossover and so I'm building my own multichannel amplifier. The speakers can handle a fair bit of power so I designed a rather powerful amp. Problem now is the required power for the whole lot and resulting heat build up. If I was doing this again I'd aim for more efficient speakers to save amplifier requirements. A fan is not welcome but now a necessity.
My situation is unique of course (and self inflicted :duh: ) but any home theater is going to need a receiver with multiple amplifiers and efficient speakers would make things easier on the amp. Perhaps aiming for 8 ohm speakers would be a start, should keep the fan quieter anyway.

[looneybomber]

Kevmurray, that's an excellent point. All the designs posted on here are great and I will likely build some just to see what they're like, but for my taste, I want speakers with a high sensitivity so I can get away with using passive radiation instead of a fan cooled amp. Unfortunaly I have fans to cool my sub amp (fan modded ep-2500), but will likely be passive for the rest of my amps.

For me, HT is less critical. It's certainly dynamic, but so is good audio. With that said, I can get by with smaller and cheaper surrounds (and even center) than my L/R's. Though I will probably have three matching mains, but then smaller, more manageable surrounds.

[littlesaint]

I would argue that for music you'd like your front L/R to be as full-range as possible to facilitate 2Ch listening with no sub. For HT, you can get away with the fronts having a higher crossover with a sub.

[joecarrow]

I agree with many of the sentiments already expressed. Good sound is good sound- music or HT will sound best when the sound is clear and free of obvious shortcomings in frequency or volume before distortion is apparent. I find that my receiver doesn't provide a subwoofer output on stereo material, so I agree that unless you can route the signal properly for subwoofer output on stereo material, then bass output is more important for a "music only" speaker than a home theater speaker.

One could also argue that HT should sound good from all over the room rather than just from a small sweet spot, since movies are more often a social thing, but I find that I have a hard time sitting still for music, so that's not a firm rule either.

I think that most of the Mission Accomplished designs will sound great for either, although the room placement requirements on some of them (needing to be farther from the back wall, have some space around them, etc) might make it a bit harder to get them to fit in your room with a TV between them.

[Kevin Haskins]

I'm designing both and I'll tell you from a design standpoint, there are a few difference in what I focus on.

HT speakers have to be a different size & format. Center channels drive the design in a lot of ways because they have to be tilted on their side and operate in a different plane of orientation. MTMs have been the traditional way of designing a center, and its a bad design choice from an acoustical standpoint. They have response issues on the horizontal plane so that kind of sucks for a center channel speaker. ;-) The other factor is that most TVs selling these days are flat. So... your speaker has to have a fairly shallow depth and operate mostly in 2Pi radiation. That drives a lot of the design because the environment its used in has a large impact on the acoustics.

HT speakers also tend not to need as much bandwidth on the bottom end like a 2-channel speaker. HT systems invariably use subwoofers and processors that have HP filters for every channel. This allows you to design smaller speakers with higher sensitivity than you would otherwise do for a system without a subwoofer.

Those are some general observations on my part. The other design features I focus on are largely the same between types of speakers. All should have good on/off-axis response, should have low distortion, easy to drive etc, etc....

[kevmurray]

...MTMs have been the traditional way of designing a center, and its a bad design choice from an acoustical standpoint. They have response issues on the horizontal plane so that kind of sucks for a center channel speaker. ;-)...

I'd argue this when the MTM is implemented in the true D'Appolito format. His original design calls for a third order crossover with the drivers spaced one wavelength of the crossover frequency from each other on the baffle. The resulting polar response is fairly constant through over 100 degrees. No worries when placing the cabinet sideways. In fact another variation uses a 2nd order low pass and 3rd order high pass to increase the output off-axis. This helps pull the stage back to the center for listeners sitting to the side.

[Dennis H]

I'd argue this when the MTM is implemented in the true D'Appolito format. His original design calls for a third order crossover with the drivers spaced one wavelength of the crossover frequency from each other on the baffle. The resulting polar response is fairly constant through over 100 degrees. No worries when placing the cabinet sideways.

Not really. Here's a 'legal' MTM with 5.5" woofers (4" piston D) and a full-size 1" tweeter crammed as close as you can get them. It's 10" c-c on the woofers, and crossed 3rd order at 1.4K which is definitely pushing the tweeter on the low end. Plots are 22, 35 and 48 degrees off axis. The response isn't too bad at 20 degrees off axis but it starts getting ugly beyond there and it has a 24dB dip at 48 degrees.

[kevmurray]

Not really. Here's a 'legal' MTM with 5.5" woofers (4" piston D) and a full-size 1" tweeter crammed as close as you can get them. It's 10" c-c on the woofers...

This is not one wavelength between the drivers. It's approx. one half wavelength which means cancellation and therefore your measurements are correct for this crossover frequency. The D'Apolito one wavelength spacing is between each driver, not between the woofers.
Was this measurement taken on a setup with adjustable crossover by any chance? I'd love to see it measured again with a 2.7k f3. I'm no expert on this , I'm learning everyday but I think I'm correct on the spacing issue.

[Kal Rubinson]

This is not one wavelength between the drivers. It's approx. one half wavelength which means cancellation and therefore your measurements are correct for this crossover frequency.

Yes. 1/2 wavelength is the generally accepted spacing maximum.

The D'Apolito one wavelength spacing is between each driver, not between the woofers.

Dunno about d'Appolito's standard but ANY two drivers spaced more than 1/2 wavelength apart and reproducing the same signals will show destructive (and constructive) interference in the plane OF their displacement.

Please note highlighted correction.

[Dennis H]

This is not one wavelength between the drivers

You're right, it's 1.03 wavelengths which I figured was close enough for guv'mint work.

Lowering the crossover so it's exactly one wavelength doesn't change the picture much. Kal is right that you need to get the spacing below 1/2 wavelength for really broad dispersion but that just isn't practical with an MTM and most drivers. An MTM on its side is okay if everyone sits near the center. Otherwise there are better configurations.

The response was modelled with one of the FRD tools.

http://www.pvconsultants.com/audio/radiation/arpe.htm

[kevmurray]

... ANY two drivers spaced more than 1/2 wavelength apart and reproducing the same signals will show destructive (and constructive) interference in the plane perpendicular to their displacement.

Yes and herein lies the magic of D'Apolito's design. His combination of physical spacing and crossover phase shift is said to minimize lobing irregularities. As I recall another option is to use two 2nd order filters which results in very little output off axis. This gives the speaker builder the option for narrow or wide dispersion depending on needs.

I have never seen any of this demonstrated but I understand Dr. Joseph D'Apolito has a very good reputation. Anyone have any experience or sources of info about this?

[kevmurray]

You're right, it's 1.03 wavelengths which I figured was close enough for guv'mint work.

Yes I got the same number for the wavelength . What I meant was, that at 1.4kHz the distance should be ~10 between woofer and tweeter, plus another ~10 to the other woofer. Or the f3 could be raised to ~2.8kHz to use the modeled spacing. This is only to satisfy the D'Apolito design. I wouldn't argue that it's the way to do it everytime.

Lowering the crossover so it's exactly one wavelength doesn't change the picture much. Kal is right that you need to get the spacing below 1/2 wavelength for really broad dispersion but that just isn't practical with an MTM and most drivers. An MTM on its side is okay if everyone sits near the center. Otherwise there are better configurations.

The response was modelled with one of the FRD tools.

http://www.pvconsultants.com/audio/radiation/arpe.htm

I have read this too and it makes sense for drivers in phase. Thanks for the link, I'm going to try playing around with it and possibly make some measurements of my own.

[Kal Rubinson]

Yes and herein lies the magic of D'Apolito's design. His combination of physical spacing and crossover phase shift is said to minimize lobing irregularities. As I recall another option is to use two 2nd order filters which results in very little output off axis. This gives the speaker builder the option for narrow or wide dispersion depending on needs.

I have corrected my original statement. Yes, d'Appolito's arrangement of drivers/crossover gives a smooth, wide dispersion in the plane perpendicular to the driver array. Thus, a vertical d'Appolito array works well in the horizontal plane (as designed) . However, the vertical dispersion, which is less critical, is irregular and that becomes the horizontal dispersion when an MTM is placed horizontally, as in many center speakers.

I have never seen any of this demonstrated but I understand Dr. Joseph D'Apolito has a very good reputation. Anyone have any experience or sources of info about this?

Joe is a well-respected designer but, as far as I know, his eponymous design is intended for vertical orientation.

[Kevin Haskins]

There is no magic to be had in the crossover. Even if you had the complete flexibility of digital filters there is no way to correct for the physical driver arrangement for over more than a window in space at normal crossover frequencies.

[Dennis H]

Ignore: just a profile for kevmurray to try to get ARPE working. PM doesn't accept attachments.

[Hdale85]

Personally I think a great HT speaker can be of lesser quality but a speaker thats good at music I usually find is good at HT as well.

[Dennis H]

What I meant was, that at 1.4kHz the distance should be ~10 between woofer and tweeter, plus another ~10 to the other woofer. Or the f3 could be raised to ~2.8kHz to use the modeled spacing. This is only to satisfy the D'Apolito design. I wouldn't argue that it's the way to do it everytime.

Go ahead and model it when you get ARPE going. I think you'll see some really UGLY response off axis vertically which would be the horizontal axis turning it on its side.

I think Joe D's original idea was to intentionally limit the vertical polar response to help avoid floor and ceiling reflections. But that backfires when you turn the speaker on its side and I don't think he would recommend it. And, in fairness to Joe, he didn't have access to all the cool modelling tools we have now when he was coming up with this stuff and I'm sure he has refined his ideas about what works best.

[kevmurray]

Thanks Dennis. For anyone else having trouble getting the ARPE workbook running in Excel, make sure you have the "Analysis Toolpak + VBA" installed. You can verify it's enabled under "Add Ins" in the "Tools" menu. I had to get out my Office disc to install it.

[SQOmaha]

If my speakers were over $100,000 I'd probably be a little hesitant to use them for HT application. But then again if I was spending $100,000 on speakers I probably wouldn't care if an explosion took out my woofer.

oh yeah I'm new here...

[cjd]

That's what I was thinking, however I see posts here that stating how the speaker will be used when posting a design question. My current L/R speakers sound great for HT but are a little lacking for music.

Well, no. They're lacking for HT also, it's just not the only focus you have so you don't notice it as much.

[itssmoke]

hello. in HT setups the center channel carries the lions share of the movie tracks reproduction. that is the one place you cant compromise. from there you must match vocals from the center to your front l/r mains. if you do that you probably havent compromised your mains , therefore they will be great for music. i guess a seperate sub is a must in HT , unless you design your mains to utilize their own powered sub per cabinet. if a compromise can be made anywhere in the HT set up(due to expense) it would be with the surrounds. but,, depending on room size and what HT your using ,, 5.1 7.1 or.... you could end up with front and rear centers , front and rear subs ,ect.

[cjd]

Thanks Dennis. For anyone else having trouble getting the ARPE workbook running in Excel, make sure you have the "Analysis Toolpak + VBA" installed. You can verify it's enabled under "Add Ins" in the "Tools" menu. I had to get out my Office disc to install it.

And Windows... only works in Windows.

[cjd]

hello. in HT setups the center channel carries the lions share of the movie tracks reproduction.

I'll disagree with this a little - the center will carry most of the dialog and the core action sound effects - however, you're going to get much more of any music or soundtrack in the mains.

C

[---k---]

hello. in HT setups the center channel carries the lions share of the movie tracks reproduction. that is the one place you cant compromise. from there you must match vocals from the center to your front l/r mains. if you do that you probably havent compromised your mains , therefore they will be great for music. i guess a seperate sub is a must in HT , unless you design your mains to utilize their own powered sub per cabinet. if a compromise can be made anywhere in the HT set up(due to expense) it would be with the surrounds. but,, depending on room size and what HT your using ,, 5.1 7.1 or.... you could end up with front and rear centers , front and rear subs ,ect.

And how do you match the placement of your center, close to the back wall and above the TV with the reflections off the TV to your mains with the front baffle a couple feet from the walls and the tv? If you don't have speakers designed to be behind a screen, all placed behind a screen with exactly the same distance to the back wall and far enough away from the side walls, and with all the tweeter heights the same, then you're compromising also. So, what's the point? Might as well go back to the speakers that come with the tv, huh?

Do me a favor and take a perfectly matched speaker, place it above the tv and tell me if pink noise sounds exactly the same.

I'm only annoyed because of the use of terms and pharses like: "you can't compromise" and "must match". This is just way to simplistic of a view and not grounded in reality.

moving on...

[technimac]

I'll disagree with this a little - the center will carry most of the dialog and the core action sound effects - however, you're going to get much more of any music or soundtrack in the mains. C

Well....maybe. :W

What I've discovered is that those doing the mixing, especially in recently released movies and concert DVD's, are emphasizing the CC much more than before. IMV, a WMTW CC format handles these demands best, and it's not essential to have it "timbre-matched" to the fronts (which in my case are Modula MT's). After all, the orientation and placement of these will be different, so why not have each do the best job of delivering SQ that it can.

On Diana Krall's "Live in Paris" DVD (in DTS 5.1 audio mode) for instance, all her vocals and piano are mic'd to the CC. With drums and guitar on the Left Front and upright bass on Right Front, it's an impressive soundstage. In this case the surrounds and backs are relegated to carrying audience applause.

OTOH in many movies and concerts, the surrounds and backs have a lot more full range material sent to them. This is especially true in movies that involve action, urban scenes, travelling, outdoor forest or jungle settings etc....or in concerts where they use the mixing board to place the listener in the middle of the band.

A good example of this is on Donald Fagen's Kamakiriad DVDA, where the opening track, "Trans-Island Skyway" (in DTS), has instruments all around - literally every speaker is used for some detailed musical output. The result is 360 degrees of musical detail. With a 6.1 system, it's like you're there, on stage with the band. :T

What this indicates to me is that it's more important now to have a center, fronts, surrounds & rears (these are probably the ones to compromise on, because they're radiating to the back of your head), capable of delivering full-range sound (at least above a ~80Hz sub x-over point).

In the movie, "Open Range", IIRC, thunder rolls from the left rear corner of the room to the front right corner...and in the climatic shootout scene, shots are coming from EVERYWHERE (most of those with pretty low transients). 8O

And it seems that sound engineers and producers on the mixing board are increasingly taking advantage of their 6.1 capability to immerse the listener/viewer in the whole "experience".

HTH, Bruce

[cjd]

I'm only annoyed because of the use of terms and pharses like: "you can't compromise" and "must match". This is just way to simplistic of a view and not grounded in reality.

Maybe YOUR reality. Some of us have acoustically transparent screens with perfectly matched mains behind it (exactly the same across the front) and... er...

So, I'm gonna go out on a limb and say, it IS important that they match, that they be timbre-matched. I can HEAR the mis-match with my current surrounds, and it drives me NUTS sometimes. I'm just not done with surround channels, but they'll match very closely with my mains (same drivers, except a 2-way not a 3-way)

All of this is still a compromise - you can't build systems without. I mean, should we all have coaxials? Or phase linear? Or... well, what's YOUR compromise?

I remember Ryan commenting the other day that the tone character of his center changed when he put it in place under the TV - it was designed for this placement, so no surprise. But then, what does that say about most speakers where their position isn't known? It's just not happening well.

[---k---]

I remember Ryan commenting the other day that the tone character of his center changed when he put it in place under the TV - it was designed for this placement, so no surprise. But then, what does that say about most speakers where their position isn't known? It's just not happening well.

Yep. When testing the center and had it out in front of the tv, it sounded a little thin and hollow. Sticking it under the tv and it sounded right. Placement matters.

And, I agree that it is best to timbre match. I obviously did, but I didn't insist on a PERFECT match center. That just wasn't happening with my current marital arrangement, and still somehow I'm very happy with my setup.

But you're right, I would be happier with yours (CJD's).

[Dennis H]

Timbre matching is a fancy word for frequency response with the speaker sitting where you're going to use it. Fortunately these days, most receivers and prepros have fancy tone controls (room EQ) that can fix that.

[wettou]

Any good quality music speaker will be great for movies just add a JL Audio Fathom F113 and you are in business

[itssmoke]

hello. dont be annoyed at my choice of phrasing. but i still think in ht set up voice matching is what you really should strive for.i might not have realized you had a standard T.V. .,but it really dosent matter. you put together a correct center , correct for your room and your application , then match your front mains to that,and your mains will be fine for music only. there are lots of choices for visual these days why T.V.? i mean we were talking HOME THEATER right? someone mentioned accoustically transparent screen. imagine that?? do you realize how many movies are almost exclusively dialog. if earlier in the conversation anyone mentioned compromise in ht set-up,, then i say dont compromise your center because of how much it is used in movie soundtracks. and like i mentioned earlier ,is this a 5.1 or 7.1 or... ?

[---k---]

hello. dont be annoyed at my choice of phrasing. but i still think in ht set up voice matching is what you really should strive for.i might not have realized you had a standard T.V. .,but it really dosent matter. you put together a correct center , correct for your room and your application , then match your front mains to that,and your mains will be fine for music only. there are lots of choices for visual these days why T.V.? i mean we were talking HOME THEATER right? someone mentioned accoustically transparent screen. imagine that?? do you realize how many movies are almost exclusively dialog. if earlier in the conversation anyone mentioned compromise in ht set-up,, then i say dont compromise your center because of how much it is used in movie soundtracks. and like i mentioned earlier ,is this a 5.1 or 7.1 or... ?

Please post a photo of your own setup.

[itssmoke]

hey listen closely to me --k-- . i tried to be nice about this comment you originally made towards my post,, but ok here we go . i cant help it if you have placement issues. thats not my problem,, it your problem ok. i mean what are you workin with over there ? you got a T.V.? 20 INCHER OR WHAT ,, THEN YOU GOT NERVE TO CALL IT A H. T. SET-UP? YOU KNOW THE T. STANDS FOR THEATER, DONT YOU? YOU SHOULD ALSO GO AND LOOK AT THE ORIGINAL QUESTION TO THIS POST , THEN RE-READ MY FIRST COMMENT ---ON--- THAT SUBJECT. I CANT BELIEVE YOU WOULD TRY AND ARGUE THE -- FACT-- THATS RIGHT I SAID -- FACT --- THAT ITS A MUST TO MATCH VOCALS IN A H. T ( T STANDS FOR THEATER) SET-UP . ARE YOU KIDDING ME?? YOU JUST FUNNING RIGHT?? BUT IF YOR NOT HERES A SUGGESTION FOR YOU .. GO TO WALMART AND GET YOURSELF AN ALL IN ONE BOX -- SURROUND-- PACKAGE AND YOULL BE FINE .. I MEAN PROALLY SOUND BETTER THAN YOUR T. V. SPEAKERS , HUH ,,, HUH ,,, HUH ??? YOU COULD THEN USE BOTH YOUR NEW SURROUND PACKAGE AND YOUR T. V. SPEAKERS. YOU DO REALIZE THAT PART OF YOUR ARGUEMENT CALLS FOR JUST USING YOUR T. V. SPEAKERS. REALLY? YOU FEELING OK? YOUR ARGUEMENT NOT MINE. HEY RIDDLE ME THIS --JOKER-- WHEN IS GOOD ENOUGH , GOOD ENOUGH?? BY THE WAY THE ANSWER IS NOT WHEN YOU HAVE THE " PINK NOISE LEVEL " CORRECT.

[itssmoke]

--k--.. lets talk about tweeter height, ok? in your world what is your perfect tweeter height? 30" , 33" , 36" , 40" ? ok now you zeroed in on your tweeter height..uh -oh heres another problem for you,in your world what about the height of your chairs,uh-oh- the height of your sofa, oh-no- what about your recliners ,, for goodness sake one of your guest's is slouching a little bit so now the entire experience is ruined!!!, i guess everything is compromised FOR YOU. do you think everyone is equally proportioned ? when seated the distance from the waist to the ear drum is the same on everyone? are you going to try and design a H.T.(T STANDS FOR THEATER) WITH A SWEET SPOT? REALLY? I GUESS YOUR SURROUNDS WILL HAVE TO BE AT THAT LEVEL TOO??? now on to the next subjectS. do you think that your mains have to be floorstanders?do you think your center has to be horizontal? are all reflections bad? whan you step outside all the sound you hear only originates at your ear level? is your "T.V." HT going to reproduce lifelike realism? in your movie soundtracks are any sounds delayed in their reproduction? do you ever hear voices?? LMAO!!!! heres a suggestion for you.. why not design yourself a "T.V." stand and incorporate your center right in the "T.V."stand. get real fancy. WHY SHOULD I POST PICTURES AT YOUR REQUEST? SO YOU MIGHT HAVE A CHANCE TO NIT ME? ITS NONE OF YOUR BUISNESS WHAT I HAVE IN MY HOUSEHOLD. I WILL HOWEVER TELL YOU THIS , A LONG TIME AGO MY FIRST HT WAS A HI-FI STEREO VCR GOING TO AN AV DOLBY ONLY AMP/PROCESSOR MATED TO A COUPLE OLD GIRLS NAMED MAGGIE, WITH THE TWO REAR SURROUNDS BEING BREWED. H.T. HAS COME A LONG WAYS SINCE THEN AND IVE TAGGED ALONG. OH YES JUST TO BE CLEAR, AT THAT TIME MY MAINS WERE JUST FINE FOR MUSIC ONLY.(I.E. ORIGINAL POSTED QUESTION)

[cjd]

Wow, way to... um... yeah. Get a grip, eh?

With that attitude I sure hope you have an AT screen, anamorphic lens, dedicated room, and a popcorn machine with all the rest.

C

[Fast_eddy]

hey smoke, you know what helps me with tweeter height?

Line Arrays

just sayin.........

[ThomasW]

End of discussion