Home theater plan? Suggestions?

[GMorris]

A buddy is building a home theater and wants me to help on the sound system... Dimensions will be apprx. 8' x 21' x 15' . Here's what I'm thinking so far:

Bass provided by two Dayton DVC 15" sonosubs on each side of screen, probably behind curtains and powered by Behringer EP-2500 (one channel per sub) and FDP.

Front mains will be Natalie P in dayton 1.0ft^3 cabinet with port but have ports plugged to cross to subs better.

Center is still in question but I'm thinking we should try a Modula MT above and below screen and make sure listeners' head will be apprx. level with screen. I'm thinking the MT's sound is close enough to the Natalie P to blend well....but won't really know until built. Potential problems here are that they will most likely be too close to ceiling/floor and rear walls but maybe some acoustic treatment could help this. These will also have ports plugged....since these will be too close to walls, will the sealed configuration help with BSC issues too?

Surrounds for 7.1 will most likely be the RS150 / RS28 design found here http://home.stx.rr.com/poneal/index.html?Page=Speakers since they were designed to be on wall and utilize same drivers as mains/center.

Probably an Outlaw pre/pro and some decent used power amps to power everything or maybe a B&K receiver...

How's this sound? Any potential problems? Suggestions?

To integrate with the subs and maximize spl, should I roll off bass at the same point for all speakers? Around 80Hz? For music listening would it be better to turn the volume down a bit and run everything full range using natural sealed enclosure roll-off?

Thanks for any input.

Greg

[ThomasW]

Sounds ok, no sense building the boxes with ports if they're simply going to be plugged.

The EP2500 is WAY to much amp for a pair of DVC15". He might want to consider a driver upgrade for the subs. There are some new better driver to be had..

My preference would be for a large midwoofer in the surrounds. The little RS150's just don't move much air.

For multi-channel just set all the speakers to small and pump the bass through the sub.

[Paul H]

I think putting one centre speaker above and one below the screen will create more audio problems than it solves.

I have one centre speaker below the screen and find it works well.

Paul

[GMorris]

Thanks for the input Thomas and Paul. I'm thinking the EP2500 would leave room for upgrading in the future and is only $50 more than the EP1500. The Dayton DVC 15" is going for $100 now so two of these is still less than one Sound Splinter 15" and the two daytons should give plenty of spl without strain...right? If one sound splinter is better (lower distortion and same or greater spl) than two daytons, we could go that route. We're trying to keep the budget under $2500 or so for all speakers (using pre-built cabinets except on sub) and sub amp but he might be persuaded to go higher.

SPLs are pretty good for the MT rolled off at 80hz so we could maybe get by with a single MT for the cc...or go with the wtmw center which gets into budget issues as well as there not being an acceptable pre-built cabinet for this design (maybe could fit into this one http://www.madisound.com/cgi-bin/ind..._id%%&pid=1442 ). I haven't found much information about setting up the center channel above and below a screen except that some people have tried it and seem to like it. I set up a small pair of old polks this last weekend in a vertical alignment just to see what they would sound like and they did produce an image between them. I think I would be less concerned if we had a 10' ceiling but the 8' may be too limiting for this set up.

I think we will construct the mains and surrounds without ports. I was thinking the more options, the better...but I don't guess the ported option makes much sense when good clean bass is provided by a sub or two. I see what you mean about the RS150s not moving enough air....I plugged it into unibox and the driver never makes it to high spl levels even with bass rolled off at 80hz.

I'm still unclear about what exactly baffle step compensation does. My understanding is that BSC affects the bass response according to the speaker's proximity to a wall or similar boundary. If the speaker is designed to be set out from the wall a certain distance, then placing the speaker on the wall would give an undesirable peak in the bass region. If the speakers (the modula MT specifically) were set to "small" and rolling off below 80hz, would there still be a peak in the response above 80hz if they were placed on the wall? If not or if the peak wasn't too high, we could go with Modula MTs all the way around.

any insight always appreciated,

Thanks

Greg

[GMorris]

Rethinking the overkill EP2500 .... I can probably adjust the budget allotments a bit by finding sufficiently overkill pro amp for significantly less on ebay. Maybe something like this QSC

http://cgi.ebay.com/QSC-USA-900-Power-Amplifier-Amp-USA900-NR_W0QQitemZ7394576795QQcategoryZ23787QQrdZ1QQcmdZViewItem

[ThomasW]

The EP-2500 isn't overkill if he moves to higher excursion subs and uses EQ or a LT circuit.

Do a google search for a Nady XA 1100. Those are frequently available for ~$150 and are a great deal. The EP-2500 is a better amp but it's more expensive.

I talked with Jon today, in the not too distant future he'll post crossover designs for all the lower cost speakers (Modual MTM, TM, NatalieP, etc) with mods for on-wall and in-wall mounting (that's the baffle step stuff you ask about)

[knifeinthesink]

Have you looked at the wtmw and tmww Dayton thread in the stickies. Pretty stellar feedback from the one or two people that have built them so far.

[GMorris]

I've been putting forth the argument for quality and ideal sound but the aesthetic argument has not been swayed (regarding the surrounds). It would not be a question if it was my personal system....all speakers would be properly placed out from the wall on stands as designed. Currently, I don't have the $2500 to spend or the dedicated home theater room so will have to be content listening vicariously through my friend's system. I would like to make it as top-class as possible though (for a given price range) and will be looking forward to any crossover modifications that will help compensate for on- or in-wall speakers.

Thanks,

Greg

[GMorris]

knifeinthesink,

The wtmw is still under consideration as a center channel especially if I can find a local cabinet maker who can construct the case for around $100 (like kgveteran did). The modula mt above and below projection screen is the other option which would probably match the system better but might not fit the room dimensions depending on how big the screen is.

Greg

[poneal]

My preference would be for a large midwoofer in the surrounds. The little RS150's just don't move much air.

For multi-channel just set all the speakers to small and pump the bass through the sub.

I've used the RS150 and it models about 104db at rated 40watt power rating. I have an 80wpc stereo receiver (HK 3380) so it's pretty clean solid power and ran the speakers full blast. There was plenty air being moved and it didn't even strain the drivers. Nice clean sound. For a surround you don't need big :E , you just need something that goes to 80 or 100hz and then cross them to a sub. Set the receiver on small speaker settings. IMHO, if 100+db isn't loud enough then you should probably start looking at pro/dj rigs where high power and loud sound is important. That's my two cents on the subject. Cheers, Paul.

[GMorris]

To realistically replicate the "Texas Chainsaw Massacre" please refer to chart below. (Ha, ha... :B ) I wouldn't want to have to wear earplugs to listen to this setup....but having the capabilities to get to those levels is intriguing. And effortlessly handling the dynamic peaks must also be a consideration. Just how effortlessly is debatable.

dB(SPL) Source (with distance)

250 Inside of tornado; conventional or nuclear bomb explosion at 5 m.
180 Rocket engine at 30 m; blue whale humming at 1 m;
Krakatoa explosion at 100 miles (160 km)[1]
150 Jet engine at 30 m
140 Rifle being fired at 1 m
130 Threshold of pain; train horn at 10 m
120 Rock concert; jet aircraft taking off at 100 m
110 Accelerating motorcycle at 5 m; chainsaw at 1 m
100 Jackhammer at 2 m; inside disco
90 Loud factory, heavy truck at 1 m
80 Vacuum cleaner at 1 m, curbside of busy street
70 Busy traffic at 5 m
60 Office or restaurant inside
50 Quiet restaurant inside
40 Residential area at night
30 Theatre, no talking
10 Human breathing at 3 m
0 Threshold of human hearing (with healthy ears)

[ThomasW]

I've used the RS150 and it models about 104db at rated 40watt power rating. I have an 80wpc stereo receiver (HK 3380) so it's pretty clean solid power and ran the speakers full blast. There was plenty air being moved and it didn't even strain the drivers. Nice clean sound.

If you're happy with them that's good.

Generally speaking we prefer not to stress the drivers. The goal being to maintain adequate headrom and the keep the distortion low at higher output levels...

[poneal]

Generally speaking we prefer not to stress the drivers. The goal being to maintain adequate headrom and the keep the distortion low at higher output levels...

IIRC, MarkK done some distortion tests on the RS150 against various other drivers of the same size. The RS150 faired very well on these tests. I think the miscommunication here is that I feel that a subwoofer is used for bass reproduction while the smaller 2 ways take over from about 60-80hz upward. Of course this being in a HT environment and using the RS150s as surrounds. So sure the RS180 will give you more thump but do you really need it in a surround? IIRC, Dolby labs specs that surrounds should receive 80hz and above so it's not like your stressing them as much as if they were run full range. Now maybe SACD sends lower signals to surrounds but most people don't have SACD players and I have my doubts that it will ever be a main staple. My feeling is that it will end up like the betamax saga of the early 80s. Cheers, Paul.

[ThomasW]

To each their own.....

I have MMG's as rears, they're set to small.

Your feelings on SACD is a discussion for a different forum.

[Jim Holtz]

IIRC, MarkK done some distortion tests on the RS150 against various other drivers of the same size. The RS150 faired very well on these tests. I think the miscommunication here is that I feel that a subwoofer is used for bass reproduction while the smaller 2 ways take over from about 60-80hz upward. Of course this being in a HT environment and using the RS150s as surrounds. So sure the RS180 will give you more thump but do you really need it in a surround? IIRC, Dolby labs specs that surrounds should receive 80hz and above so it's not like your stressing them as much as if they were run full range. Now maybe SACD sends lower signals to surrounds but most people don't have SACD players and I have my doubts that it will ever be a main staple. My feeling is that it will end up like the betamax saga of the early 80s. Cheers, Paul.

Hi Paul,

Isn't the 80 Hz. and above spec for Dolby Pro Logic rather than 5.1? My understanding is that 5.1 is full range for all 5 channels. I run my system in the full range mode on all channels. You'd be amazed how much bass is in the rear and center channels.

Jim

[poneal]

Hi Paul,

Isn't the 80 Hz. and above spec for Dolby Pro Logic rather than 5.1? My understanding is that 5.1 is full range for all 5 channels. I run my system in the full range mode on all channels. You'd be amazed how much bass is in the rear and center channels.

Jim

Hi Jim, it had been awhile since I read that article so I googled it and came up with the following:

http://www.dolby.com/assets/pdf/tech_library/4_Multichannel_Music_Mixing.pdf

Check out chapter 4 Bass Management. I think that most DVD movies use this format (LFE dedicated channel). We must remember that the receiver can change all this too. If you set all speakers to small then depending on the crossover of the receiver will determine the lower freq. sent to the sub. My particular AVR works this way. If all speakers are set to small then I have a choice of 80hz or 100hz xover. If I choose 80hz, then 80hz and below will be sent to the sub. Of course we know that some part of the FR is sent that is greater than 80hz because of xover slope. Now musicians don't like to heed the dolby recommendations so that's why I mentioned SACD which goes in another forum as posted above. Of course this is all only a guideline from dolby so some follow it some don't. As is a lot of things in the world--clear as mud! LOL.

[Hdale85]

How do you setup large 3 way speakers and use a sub as well? of course i'll be useing hypex amps and a Outlaw Processor but i believe the outlaw has speakers settings the same as well? im going to be building the un named RS-3 ways that are in the stickys and will eventually build a sub or 2 to go with them just curious lol just a thought that crossed my mind while i was reading your post. Im not much familiar with Pre Pro's and amps ive only used recievers prior to the system im working on building now lol.

[Jim Holtz]

Hi Jim, it had been awhile since I read that article so I googled it and came up with the following:

http://www.dolby.com/assets/pdf/tech_library/4_Multichannel_Music_Mixing.pdf

Check out chapter 4 Bass Management. I think that most DVD movies use this format (LFE dedicated channel). We must remember that the receiver can change all this too. If you set all speakers to small then depending on the crossover of the receiver will determine the lower freq. sent to the sub. My particular AVR works this way. If all speakers are set to small then I have a choice of 80hz or 100hz xover. If I choose 80hz, then 80hz and below will be sent to the sub. Of course we know that some part of the FR is sent that is greater than 80hz because of xover slope. Now musicians don't like to heed the dolby recommendations so that's why I mentioned SACD which goes in another forum as posted above. Of course this is all only a guideline from dolby so some follow it some don't. As is a lot of things in the world--clear as mud! LOL.

Paul,

I read the document and it still seems that a full range signal is sent to all 5 channels. The chapter indicated focused on monitor size speakers and bass management with a sub.

If you have speakers that are capable of full or extended bass, I would not roll them off at 80 Hz. I have a 12" sub built into the bottom of eack of my Omegarrays plus a 15" sub that I roll in for movies only. The rear speakers have good bass down into the 40's so I run them full range also. I don't use any bass management in my Pre/Pro. I have 24 DB crossovers built into each of the plate amps that do a great job of taking care of the bass.

If I had small monitor size speakers, then yes, setting it up for small would be appropriate, but not with full range speakers. More to the original point, a full range signal is available to all 5 channels if you choose to use it.

Jim

[poneal]

Yeah, I just reread it

and the mixing engineer can code content below 80hz to all channels. I think a majority of people would rather have small speakers for surrounds and large for mains though. My mains are capable of mid 20s and I have them set to large + LFE and my center and surrounds set to small with 80hz for a xover setting. So to the original poster, if you can accomodate 5 or 7 or more large speakers and don't mind the space they take up then by all means go full range on all of them. I'm guessing that 90% of the population probably uses smaller speakers for surrounds and add a sub. As for the original post, I think with his budget and customer wants that smaller surrounds is what he that person wants. Of course I could be wrong and that wouldn't be the first time :-).