Home Theater Design Advice

[kctess5]

So I'm working on designing a home theater sound system for my parents and I'm a bit lost. I'm used to designing stereo speakers but I really have no idea about design considerations for home theater systems.

I need to keep the price down so I was thinking a single full range would be the best option to avoid crossover + multiple driver expenses. I was recommended the CSS EL70 by Dave (Planet10) but I'm a bit worried about their power handling abilities. The system needs to be pretty loud for use while in the next room over (not separated) and I don't want to blow the drivers. I will most likely be low passing the speakers around 80 or lower Hz so that should help save them.

I will have the two mains in our home entertainment center behind speaker grill material so they can be hideously unattractive and pretty large (MAX 11" high by 18" wide by 21" deep). The rears will be mounted in the ceiling (I know its not optimal...) and I don't know if they will need a cabinet or if I can just use the ceiling as a cabinet. The center will be very similar to the mains in terms of placement, in the same entertainment center.

The system needs to have a pretty broad sweet spot over the whole couch or I know my parents will be unhappy. I don't know if these drivers or full rangers in general will be too directional for this.

What I'm thinking is bass reflex all round except for the center which needs to be really clear for vocals so I was thinking sealed to have less bass coming out of it.

Any suggestions? I'm lost...

The total cost should probably be under 250 or so for the drivers, with some wiggle room if its worth it.

Thanks all!

[GM]

Sounds like you’re going to need a separate sub system and run all the others as ‘small’.

I haven’t had much luck using small FR drivers in relatively large spaces, especially at long listening positions, so used either car audio co-ax or PA drivers like this one except back then it carried Altec labels and had an AlNiCo motor: Electro-Voice 409-8E | Performance Audio

http://www.google.com/url?sa=t&rct=j...FW5wNxlbbZqnYA

With their high Qt, they can be put in damped open back boxes and ‘as is’ in the ceilings, all XO’d via the HT receiver. Of course you’ll need to shelve the tweeters some, but where high intelligibility and a certain amount of directivity is required, this type of driver excels.

Anyway, there’s quite a large selection of this type driver to choose from and probably quite a bit cheaper in some cases plus there should be 12” available also, which is better for long throw apps such as yours, though can’t comment on how well they might compare sonically to this somewhat premium line.

GM

[chrisb]

By now it's no secret that I'm a fan of the simplicity of using smallish FR drivers in a HT system, for an appropriate sized room ( approx 320sq ft in my case), but Greg is quite right that at "realistic" levels in a much larger space, little guys like the EL70 could be in over their heads.

Even with full bandwidth LCR speakers, separately powered "Subs"/ LFE channel woofers are a given part of any true multichannel system, so you may well be able to get the required performance for the front row from drivers less than 12"

One thing that car audio and PA drivers are engineered to handle is power and high SPLs.

[kctess5]

Of course you’ll need to shelve the tweeters some

Sorry what does this mean?

I should have mentioned earlier that we do have a sub which is why I don't mind low passing the LCRs. I don't remember but I believe its a polk 10" BR

How does the sonic quality of P.A. or car audio speakers compare to home type speakers. Maybe this is a misconception but whenever I hear those words I get skeptical and think more mass market low-fi.

What sort of power handling do you guys think I need for a home theater (not including the sub) for pretty loud but not eardrum rupturing performance. I noticed that those E-V speakers can hit 112 dB

[chrisb]

Originally Posted by kctess5

Sorry what does this mean?

I should have mentioned earlier that we do have a sub which is why I don't mind low passing the LCRs. I don't remember but I believe its a polk 10" BR

How does the sonic quality of P.A. or car audio speakers compare to home type speakers. Maybe this is a misconception but whenever I hear those words I get skeptical and think more mass market low-fi.

What sort of power handling do you guys think I need for a home theater (not including the sub) for pretty loud but not eardrum rupturing performance. I noticed that those E-V speakers can hit 112 dB

If you don't already own or have access to one, I'd strongly suggest getting your hands on a cheapie Radio Shack or equivalent SPL meter, then sit down for a listening session with your folks in the room(s) in question - drag your own system from home if necessary. I'd like to be able predict what volume levels they'd find sufficient, but unless you already know that, it's all supposition.

Yes, some cheaper car audio speakers are crap, but there are many that have power abuse limits beyond that of mainstream home speakers - however as they are designed for much different conditions, not all perform well in 400+sq ft rooms. If you conclude that conventional drivers intended for domestic use won't be sufficient, I'd be inclined to look a smaller PA / sound reinforcement rather than mobile audio drivers.

[kctess5]

For a short time i had one and it didn't work so i returned it and now i cant bring myself to spend that much on such an overpriced device at radioshack (I don't like their philosophy). I'll look into some larger more powerful full rangers and if i cant find something sufficient ill have to look into two way options and figure out the cheapest possible crossover. Dayton has some good looking long throw mid bass extended range drivers

[sreten]

Originally Posted by kctess5

I'm used to designing stereo speakers but I really have no
idea about design considerations for home theater systems.
Thanks all!

Hi,

This page is a good read regarding HT system issues :

Zaph|Audio - ZA5 Speaker Designs with ZA14W08 woofer and Vifa DQ25SC16-04 tweeter

FWIW I consider off axis issues (no treble to speak of)
of decent sized FR's used for HT a major issue.

rgds, sreten.

[kctess5]

That link is broken but I'd love to read it. If anyone knows of other good reads about ht design that would be great also

FWIW I consider off axis issues (no treble to speak of) of decent sized FR's used for HT a major issue.

This is true with my experience too. My tang band 3" full range line arrays are like lasers, its impressive, but this also comes with good imaging imo, of course this isn't good for ht use

[Speedskater]

Are we talking about a modern 5.1 or 7.1 channel discrete system? As older 3 or 5 channel encoded logic systems had different frequency response and directionality requirements.

[chrisb]

Originally Posted by kctess5

That link is broken but I'd love to read it. If anyone knows of other good reads about ht design that would be great also



This is true with my experience too. My tang band 3" full range line arrays are like lasers, its impressive, but this also comes with good imaging imo, of course this isn't good for ht use

Link worked fine for me - looks like a well considered, modular family of designs, and using multiples of the same drivers certainly makes a helluva lot of sense for a HT rig. Personally, I'd not be inclined to go for much larger than the TMM tower as mains - leave the heaviest lifting ( below 120 or so) to separate subs - if the room is large enough that you're uncomfortable with small full-range drivers, it's very likely that at least 2 woofers will be the best approach for even distribution of low frequencies.


Meeting your target budget with multiways of this quality will be rather a challenge.