Home Theatre & 2 Channel Together - can it be done??

[Peter_F]

With all the buzz on room treatments and measurements, I wondered if it was possible to have a HT setup and a 2 channel system in the same room running independent of each other without room requirements and treatments impeding on each other?

I suspect perhaps bass trap implementation may work for both systems, but what about acoustic panels and diffusers?

So I guess I'm asking if I had my room measured and problem areas were identified and corrected for 2 channel listening, would that be detrimental to the HT setup?

Is it a case of accepting the best compromise for both setups?

Presently I don't have any areas of concern in my room which I have identified. In the quest to extract the most out of both systems, and the room, I wondered what things I should consider to integrate both setups harmoniously and efficiently?

I intend to have my room measured at some stage in the near future, but wanted to know upfront what I can expect when attempting to maximise one room for 2 x systems.

Cheers

Flemo.

[Guest Peter the Greek]

Why bother? Just plan for ht and listen to 2 channel content in 2.1 - generally smacks the pants off stand alone 2 channel.

[Paul Spencer]

Good question Flemo, it's certainly an interesting one. Is this the same room you had in the past when you had B&W speakers and some cream/beige absorbers put on the walls? As I recall a relatively normal living/lounge room?

Firstly the easy one ...

I suspect perhaps bass trap implementation may work for both systems, but what about acoustic panels and diffusers?

As you suspect, I would start with bass traps in almost any room, as many as possible, as big as possible within acceptable limits, often being creative in how to get it to work visually, always a compromise between performance and looks. I'd do that for just about any system and room regardless of whether it's 2 channel vs HT. It should improve any system because the bass will just be tighter, due to the more rapid and even decay in the room from 40 Hz up into the midrange. The bass part is easy - you want as much trapping as you can get. The variable is whether you want those bass traps to also absorb all the way up, or have a membrane to limit them to the modal range ie bass.

The big difference in terms of treatment is that HT rooms want to be a bit more dead than a 2 channel system. The use of surround channels to create the desired ambience and also the higher priority on speech intelligibility and perhaps more precise imaging means more treatment and a lower reverb time, more like about 0.2s. You want vocals more precisely imaged with less sound from the room.

Example. I moved away from open baffle speakers partly because I didn't like the way they imaged vocals on movies - too vague. Their strong front wall reflections extends the apparent size of voices, fine for music, it feels like an enhancement (though not to all), but for voices it was a problem.

In my room that ambience is about right for HT, around 0.2 as I recall. It's a small room and thus quickly gets dead, all that coming from the bass traps with no membrane - temporary traps waiting for current speakers to be finished, as the speakers will be built into the main traps. For 2 channel I would prefer more ambience, a figure I've heard suggested is 0.4s RT for 2 channel.

So what you have is a compromise. Let's say you accept that 0.2 is right for HT and 0.4 for 2 channel. Do you go with a compromise of 0.3s? Do you make the room a bit more live with music the priority and then accept that HT gets less priority? Or do you go with a more dead room and find that you really don't mind it? I put this down to personal preference. I know there are some that prefer a more dead room for both, so for them it's not a compromise. However, I think most people would prefer a room that has a bit more of its own signature, which is probably more like RT0.4s. It depends both on your preferences and the signature of your room. Many systems at the show (did you visit?) to me sounded like the signature of the rooms was a bad thing and I preferred the Equinox room in general which was made more dead, to the fairly poor sounding small rooms at the show.

When you get your room measured, have in mind some things you want to achieve. I have measured rooms for people, and the usefulness of those measurements is related to how they actually use that information. I've measured some in which they just wanted to see what they had going on. I'll be honest, I didn't think that was particularly useful! On Sunday I went over to measure a HT room, quite a big room with two subs coming. We measured all the spots where subs could be placed, from a couple of listening positions. That was very useful for a couple of reasons. First, it indicated that where he intended to put subs was a good spot, and we found two is better than one. It also showed the bass that results in front and back rows, each with different rows. You could not get both of them right with the two positions, however, we did discover if he wanted to go a further step, then a third sub would improve the back row a great deal if the front row was optimised for the main 2 subs. We also found that the back row got a lot more extension with significant midbass chunks taken out. The front row, the one that feels the most natural place to put the prime seats, were generally smoother but had much less extension. That's very useful info! It immediately suggests some design choices.

I wondered what things I should consider to integrate both setups harmoniously and efficiently?

1. Use those measurements to optimise the bass - speaker, sub and listening positions. I've outlined my take on that in my bass integration guide. You will tend to benefit most there if you carefully choose positions and also use bass traps and EQ. If done right there is no reason not to use the bass setup for music as well. If you have to switch off the subs for music then it suggests something isn't right.

2. Toole in "Sound Reproduction" has some very useful info on this general topic.

3. Give yourself time to choose your treatment scheme. Throw up some foam, listen, reduce it. I prefer to do it that way rather than commit to building or buying without having spent some time with a given scheme. What sounds good at first, you may change your feelings over. What sounds dull at first, might sound right after a while.

So is it a compromise? Not necessarily. If I had to guess, for you it probably is a slight compromise one way or the other. You just might end up biasing a little towards 2 channel with a bit more liveness in the room than a typical HT setup. That's my guess.

[Drizt]

I have visited many people who have combined HT / 2ch set ups and some of them have been better than others (obviously). Those that have taken the time to measure, find the best placement, add room treatments, add multiple subs and perhaps some EQ where required have generally been in the better category. Personally I think it is very doable to have a successfully combined system. It can be done, that is certain.

[Peter_F]

Is this the same room you had in the past when you had B&W speakers and some cream/beige absorbers put on the walls? As I recall a relatively normal living/lounge room?

Hi Paul, yes mate the same room with the formal lounge and dining room coming off to one side.

I would start with bass traps in almost any room

That was going to be my first area as well, particularly as I was intending to integrate 2 x subs into the HT set-up. It's still debatable if subs will be a part of the 2 channel set-up, but open minded at the moment.

I take it the placement of the bass traps would depend on how the room measures, or are they are generally installed in the corners, floor to ceiling?

The variable is whether you want those bass traps to also absorb all the way up, or have a membrane to limit them to the modal range ie bass.

Hard to say at this stage until I have the room measured and then I guess determine the totality of what treatments (if any - you never know!!) are needed.

The big difference in terms of treatment is that HT rooms want to be a bit more dead than a 2 channel system.

This was one of my concerns, but it's finding that balance or a good compromise.

You just might end up biasing a little towards 2 channel with a bit more liveness in the room than a typical HT setup. That's my guess.

Yepp, spot on mate! I would always subscribe to less is more, particularly anything to do with this hobby and would go with a bit more liveliness.

I intend to run a 7.2 HT setup and in the process of maximising the room, I wish to get the most improvement or performance by using the least possible amount of visible room treatments. As the systems are in the front room(s) of the house I want it looking as good as it sounds.

Thanks for your input Paul.

[Peter_F]

I have visited many people who have combined HT / 2ch set ups and some of them have been better than others (obviously). Those that have taken the time to measure, find the best placement, add room treatments, add multiple subs and perhaps some EQ where required have generally been in the better category. Personally I think it is very doable to have a successfully combined system. It can be done, that is certain.

Hey Drizt,

I haven't been able hear a setup with 2 x systems integrated in one room. I guess I'm one of the few, nope, the only one I know who is attempting to maximise both systems in the one room.

[Paul Spencer]

That was going to be my first area as well, particularly as I was intending to integrate 2 x subs into the HT set-up. It's still debatable if subs will be a part of the 2 channel set-up, but open minded at the moment.

I would say it depends on whether you get them to sing or not. If you get them "good enough" just for explosions, then you won't want them for music. If you go the whole hog and get them fully optimised, then you will get better bass that way. By going the whole hog, I mean starting with top notch subs (not necessarily that expensive), placed where they work best (make sure your measurement guy measures all the positions in which they could go), EQ as needed to tame the peaks (again this needs to be optimised with measurements, you can't guess that one), and enough bass traps so that the modal ringing in your room is fully controlled. It's quite a task to get it right and it can be a tedious process to get there. Most people don't put in the effort and don't want the learning curve and also aren't quite enthusiastic to do everything that needs to be done. The result is that the sub gets turned off for music. If the bass isn't better with the subs on, you haven't arrived.

I take it the placement of the bass traps would depend on how the room measures, or are they are generally installed in the corners, floor to ceiling?

If you use resistive broadband traps, then they are basically just giant absorbers that work like midrange panels, except using dense material is critical, they need to be thicker and spaced away from the boundary. Yes - put them in corners - they go there because that is where bass gathers. Keep in mind that in a rectangular room you have 20 corners. It pays to distribute them, and also consider bulkhead traps (don't go smaller than 1 x 1 ft). Generally they should be about the size of a door on the diagonal. I recall some speakers you built a while ago that show you're quite handy, so I'd guess your best chance at doing this well and not becoming a batchelor is to build them to fit nicely.

You're probably best to put pegboard on the front as a membrane so they won't deaden the room, then wrap them in fabric (maybe even a light colour to match the walls).

Another thing to try is diffusers. I've seen some cheap on ebay in the past. They take some time to build your own. Diffusers won't make a room dead and the idea is to send reflections along a longer path so they arrive later and lower in level. The effect is a bit like making a room sound bigger. With a bit of creativity they can also appear as decoration and win some points.

One way to reduce room treatments is to go for speakers that suit an untreated room. Dipoles, horns, waveguide speakers interact differently with the room and tend to reduce off axis sound. In effect it is like the speaker itself has "built in treatment." Small speakers like say an ML1 have wide dispersion so they illuminate a room differently. That would tend to lead to more treatment than a speaker with controlled directivity that prefers a more live room. I recently measured my latest horns and was really surprised to see that they control dispersion all the way down into the lower midrange, just like an open baffle speaker. The sound is totally different in terms of room interaction. For you it would probably be quite a shock. (It's not for everyone). Actually it was a shock for me as well. At first I was inclined to miss the missing room sound I was accustomed to, but at the same time also noticed startling clarity and sharp imaging. I don't expect you will go down this path, but I just throw this in for interest.

[DoggieHowser]

One of the problems that I have encountered are diffusers behind the main speakers on the front wall and in the middle. You can't really do that with a big projector screen setup.

Corner bass traps are ok.

First reflection points shd be where the wide speakers are.

[ArthurDent]

So I guess I'm asking if I had my room measured and problem areas were identified and corrected for 2 channel listening, would that be detrimental to the HT setup?

It's not going to be that detrimental as very few domestic HT rooms get their RT60's down to the ideal 0.2s anyway as it takes a lot of treatment to get down to this. A higher and ideal for 2 channel audio RT60 time will simply give you a bit more reverb for HT. Your AV processor/amp no doubt has many surround modes some of which will dial in even more reverb/ambience, some less, so just use the one that sounds the best.

All this of course is assuming that 2 channel audio is your priority.

[ArthurDent]

One of the problems that I have encountered are diffusers behind the main speakers on the front wall and in the middle. You can't really do that with a big projector screen setup.

You can but it involves a bit more work in moving the screen forward and off the wall.

[Guest Peter the Greek]

AT screen?

[ArthurDent]

AT screen?

Yeah that would work (in allowing acoustic treatment to be place behind the screen and sort of work) but not for me as I don't like them at all. Of course that's not to say that anyone using one is getting it wrong but I prefer not to compromise the picture or the sound.

[Guest Peter the Greek]

Some would argue sound is compromised for HT given that the speakers aren't positioned correctly unless behind a screen....

[ArthurDent]

Some would argue sound is compromised for HT given that the speakers aren't positioned correctly unless behind a screen....

Some not only would but do and mostly they'd be wrong. Both Dolby and DTS are pretty specific about where the main front and right speakers need to be in terms of the angle between them and you. Assuming you'd using a normal seating distance of 2 -3 times screen height this usually places the main L & R outside the screen area, not behind it.

[Guest Peter the Greek]

Center?

At same height as mains? same design as mains?

2.35 screens?

Speakers at correct heights relative to screen?....the list goes on and on for something that IF there is any loss its at HF which can be easily tweaked with a little EQ

[ArthurDent]

Center?

At same height as mains? same design as mains?

2.35 screens?

Speakers at correct heights relative to screen?....

All of which can be sorted without resorting to putting any speakers behind a screen but yes centre behind an AT screen if you can EQ it to match the mains and don't mind the hit your image quality takes then why not, but not for me.

[Peter_F]

Hi Paul,

I would say it depends on whether you get them to sing or not. If you get them "good enough" just for explosions, then you won't want them for music. If you go the whole hog and get them fully optimised, then you will get better bass that way. By going the whole hog, I mean starting with top notch subs (not necessarily that expensive), placed where they work best.

With obtaining top notch subs, which ones, or DIY type (especially the not necessarily that expensive type) would you suggest that would work well with HT and a 2 channel setup?

As I run the systems independently of each other, except they share the main speakers, can these subs be connected to the HT and 2 channel setup, or would they need to be disconnected and reconnected to suit. Also would the sub settings be different for each system or the same given they would be tuned or calibrated to the room?

(make sure your measurement guy measures all the positions in which they could go), EQ as needed to tame the peaks (again this needs to be optimised with measurements, you can't guess that one), and enough bass traps so that the modal ringing in your room is fully controlled. It's quite a task to get it right and it can be a tedious process to get there. Most people don't put in the effort and don't want the learning curve and also aren't quite enthusiastic to do everything that needs to be done. The result is that the sub gets turned off for music. If the bass isn't better with the subs on, you haven't arrived.

A good tip to remember!

If you use resistive broadband traps, then they are basically just giant absorbers that work like midrange panels, except using dense material is critical, they need to be thicker and spaced away from the boundary. Yes - put them in corners - they go there because that is where bass gathers. Keep in mind that in a rectangular room you have 20 corners.

I’m having visions of Batman’s cave treating 20 corners!!

It pays to distribute them, and also consider bulkhead traps (don't go smaller than 1 x 1 ft). Generally they should be about the size of a door on the diagonal. I recall some speakers you built a while ago that show you're quite handy, so I'd guess your best chance at doing this well and not becoming a batchelor is to build them to fit nicely.

Yepp no problems building something like that. I’m probably just not prepared to have the room “overwhelmed” with the physical appearance of treatments. I could settle for a good looking compromise though, and so would the wonderful Mrs Flemo!!

Another thing to try is diffusers. I've seen some cheap on ebay in the past. They take some time to build your own. Diffusers won't make a room dead and the idea is to send reflections along a longer path so they arrive later and lower in level. The effect is a bit like making a room sound bigger. With a bit of creativity they can also appear as decoration and win some points.

Do you have any links to reasonable looking diffusers, and general DIY ones as well?

Small speakers like say an ML1 have wide dispersion so they illuminate a room differently.

Pound for pound, and with room interaction the ML1 is the best speaker I have heard. Based on that, upgrading or attempting to move sideways by changing speakers to assist with treating the room is something I would likely resist.

Actually it was a shock for me as well. At first I was inclined to miss the missing room sound I was accustomed to, but at the same time also noticed startling clarity and sharp imaging.

What you have described is IMO the sound of the ML1 speaker, startling clarity and sharp imaging.

Perhaps my room “may” have more overall improvement potential relating to bass management and not so much with the mid and upper frequencies. I guess that comment is based on my perceptions of the 2 channel sound and may not apply to the HT aspect? I accept that it is also speculative without formerly measuring the room.

I have had many things pointed out about my system and components over the years but nobody has ever mentioned (to me) that the room was considered to be an acoustic liability, or something I needed to address as a priority.

Cheers, flemo.

Edited November 8, 2011 by flemo

[Juicester]

reading this thread with interest flemo, as I'm in a similar boat (i.e. combining systems, only now considering the room treatment as being an essential upgrade and aesthetics being important for WAF).... best of luck - and post your development/ findings as you go!

Chris

[Craigandkim]

Well,

Im pretty happy with my 2 channel & multi-channel seperate/combined set-up. Mains are 2.80m apart, 3.15m from listening position. Speakers adequately produce a very fulfilling sound stage in two channel, but I prefer a well mixed multi-channel presentation any day.

Centre channel is almost at the same height as the main tweeters with a 2.37 screen: here

PS: Integra 80.1 for HT, Audiogd C-39MkIII and/or NFB-2 DAC for stereo

Here is the placement of speakers & screen (pretty close to scale)

Edited January 5, 2012 by Craigandkim
speaker placement

[Peter_F]

All this of course is assuming that 2 channel audio is your priority.

It seems to go in cycles these days. At the moment I'm really enjoying the HT more than I thought I would after purchasing a Denon AVR-4311 and BDP. The HT is certainly getting a lot of use with my teenage kids as well. When they're on holidays I struggle to get in the room and watch my shows! Since getting a TiVo and the new AVR, even FTA broadcasts have really impressed me. Some FTA shows are almost as good as watching a DVD. I have also been impressed with HDMI even though I have read a lot of negative comments about the format recently.

Cheers, flemo.

[Peter_F]

reading this thread with interest flemo, as I'm in a similar boat (i.e. combining systems, only now considering the room treatment as being an essential upgrade and aesthetics being important for WAF).... best of luck - and post your development/ findings as you go! Chris

Hi Chris,

Yes it will be interesting to see what I come up with in the end.

I think I will get my room measured first to see if 2 x subs is a viable option. There's no point spending money on something I don't need and with my philosophy of less is more, maybe a single sub is all that's required? Or even maybe a single sub for each system will prevent each system contaminating or compromising the other? Crazy stuff this hi-fi / HT caper!!

Cheers, flemo.

[Guest Peter the Greek]

Centre channel is almost at the same height as the main tweeters with a 2.37 screen:

Screen looks way to high? shouldn't be more than 15 degrees from eye level to top of screen - my personal preference is for the middle of the screen to be in line with eye level......but that's just me

[betty boop]

Hi flemo,

I combined my 2ch and ht equipment in the one room about 8 years ago and was probably one of the best things I did. It was to the benefit of the 2ch side as it put my system in a better room, and was for the better ht wise as it incorporated my better 2ch speakers and amps into the av side. The other major benfit was it leaves just one system to concentrate on rather than being distracted by two.

The big part in this is indeed the room. I followed my speaker manufactuers suggestions re room setup for a blend of reflective and absorbing materials/furnishings in the room and been very happy with the end result. With an absence of audible slap echo and yet not being audibly dead to the point of some ht rooms where its more like an anechoic chamber !

So yes can be done, and you are not alone, theres quite a few peoples rooms have visited that have achieved pretty good result for both in the same room. And I'm not talking about where they maybe do 2ch well and HT is ok. Or other way around in these cases they do both ht and 2ch extremely well…so certainly achievable.

[betty boop]

Hi Chris,

Yes it will be interesting to see what I come up with in the end.

I think I will get my room measured first to see if 2 x subs is a viable option. There's no point spending money on something I don't need and with my philosophy of less is more, maybe a single sub is all that's required? Or even maybe a single sub for each system will prevent each system contaminating or compromising the other? Crazy stuff this hi-fi / HT caper!!

Cheers, flemo.

Be interesting indeed what do come up with flemo. I added a duplicate sub to my system some time ago, and tried in few different variations as stereo subs and then with both for lfe duties. With not really getting huge gains over the single sub. I decided to just as your suggesting. Ie one for ht working off my denon, and the other I have set up to work off the 2ch side to extend my mains. That works great for 2ch with the one sub and by default wooing with my mains the 2ch sub gets utilized for ht as well. Ps I dont know if using audyssey for ht and dialing in the subs but I find it bloody brilliant

[Peter_F]

I dont know if using audyssey for ht and dialing in the subs but I find it bloody brilliant

Hi :)al,

I'm hoping to recalibrate the Denon using audyssey when my additional surround speakers arrive. Currently I perceive an issue with the centre channel/speaker and hoping to sort out if its a problem with the speaker, calibration or even placement. IMO it's just not sounding right at the moment and niggling at me!