Altec Home Theatre?

[Carl Bill]

I just got approval to add on to the house and build a home theater (as well as a few other things).

If I planned to use 828's with 416's and MR594's with 299's, as mains, what size room do I really need? I have to reasonable, but what dimentions do I need to plan for?

Do I also need to have 800/900 drivers for the higher end?

I appreciate any and all suggestions.

[Carl Bill]

Thanks for the info!

I am planning on a DLP projector on to a screen. So I would like to get a screen size as large as is realistically appropriate with a 9' ceiling.

I expected that I would propably need subs. I will have to start from scratch and build new enclosures and find decent drivers.

I have several electronic crossovers on the shelf, but will consider something else if necessary.

Also thinking of a new Dell computer for the processing of the surround sound. I have been told that this is now the best way to go. Any other options will be considered. Any suggestions are appreciated.

[bfish]

Hi, C.B.!

Congrats on the approval! Designing a room to fit the system should get you some awesome results! Will there be a marquee out front? How much for admission?

Don't know the details, but if you'll end up with unused attic or crawlspace, you might want to consider a built-in IB sub, or even a sub horn.....can you get by without windows?

Do you have a plan for the HVAC? I might be able to help in that area.

[GM]

Greets!

DD/DTS reference is 105 dB/20-20 kHz/viewing position for all channels except the LFE, which is 115 dB, so maybe the 299s once shelved can be EQ'd enough, otherwise Tangerines on appropriate horns will get you there. The 828s can barely make it to 80 Hz with any authority, so using bass management to route everything below 80 Hz to the LFE is desirable, but this increases its peak requirements to ~122 dB/viewing position.

Assuming a front projector, the viewing distance when horns are used tends to be a function of how deep a horn can be tolerated since as it increases it also increases the horn's length to narrow up the coverage angle, so draw a scale plan view using 60-90 deg to see what's required for the CC to cover the desired seating area and from all this info I can calc the optimum room and screen size.

GM

[GM]

Greets!

This isn't a practical way to go about it unless you have very deep pockets since for 16:9 it can be 9 ft tall x 16 ft wide with a minimum viewing distance of 24.64 ft, or 21.15 ft wide/second row of seats at 32.57 ft for 2.35:1. All assuming a consumer grade DLP can handle it of course, which I seriously doubt.

WRT to XO's, a mix of active/SS on the bottom and passive/tubes for the horns will yield the smooth dialogue of bygone days with the slam factor/control of current systems required for action/audio special effects of today.

Yeah, HTPC is where it's at along with touch screen remotes.

GM

[Carl Bill]

Thanks for the info! Lots to consider, but I don't have to nail down the floor plan for almost 2 months.

I expect to use trusses for the roof structure and a concrete slab. So I don't know if that will work well on subs. I am open to any sub design for the application. I assume I could use some of the attic space if that works well.

I am currently considering a Mitsubishi HD4000U projector. 9' high screen may be a bit much. More like 7 - 8' high will probably be pushing it. Model subject to change with new product availability.

HVAC has not been determined, but I expect it to be a natural gas upflow unit with external compressor for AC. The unit will likely be in a centrally located closet away from the HT. I guess there are ways to dampen the noise from the air flow to get down to a quiet noise floor. I would listen to more on how to do that.

Any all suggestions welcome. I want to try and get it done right and I have not been keeping up with much of this stuff. I have plenty of Altec parts to put together and already have the Model 19's. I was thinking of the 19's for rear channel speakers, assuming they are capable.

[GM]

Greets!

Well, until you have a better idea of what the equipment will do, etc., I'm at a standstill.

WRT the LFE channel, placing subs around the room where they will work best is a good plan if it's not too large, otherwise making one for each channel and located near it is best.

A fairly large ~acoustically transparent screen can be DIYed relatively inexpensively, but one this big will have to be a pricey commercial one AFAIK.

Typically, surround channels blend best when fired down from above, so M19s could work if 'flown' upside down, but if you go with my suggested layout, which is straight out of the Davis's book, Sound System Engineering, they may can be fired into the rear corners to get the necessary dispersion if special padded grills are used.

With big horns up front and pretty big horns in back, you'll need pretty big horns to the sides also, and more than one to keep from having holes in the 3D soundfield of such a large room.

I know basic HVAC design, but haven't had the need to use it in decades, so am a bit 'rusty'. Anyway, it's the installer's problem to get it right.

GM

[LICORNE]

Hi,

One important step is to visualize what you want.
Is it a screening room or home intertainment centre.

The screening room is more expensive.
1 screen (perforated)
2 Overhead Digital projector
3 Surround speakers
4 Rear screen speakers or (mains)3


http://www.geocities.com/rafaleconve...?1147216601980


..........................................

[Carl Bill]

Appreciate the info!

I am open to all suggestion as I do not have enough knowledge to know exactly what I am doing. I am open to all suggestion. I can build cabnets and get Altec parts up to par for a working audio system, but beyond that, I am way behind.

GM: I assume you are refering to Don and Carolyn Davis. I think they wrote the book on audio, so I would guess they would know. I can do alternate rear channel speakers if the Model 19's are not optimal. I am open to sub suggestions. I think I met them one time several years ago at NSCA.

I am hoping to get enough input here to do this right the first time. Although I worked for Altec, have some audio engineering experience and have some historic knowledge of what went on at Altec (OKC) at a point in time, I do not consider myself a knowledgeable home theater expert by all means. I am just learning.

So, that said, I would like all the help I can get. I appreciate the input.

[GM]

Greets!

GM: I assume you are refering to Don and Carolyn Davis. I think they wrote the book on audio, so I would guess they would know.

<font size="2" face="Verdana, Helvetica, sans-serif">Hardly, their book is basically a compilation of other's research. I mean this isn't to imply that they haven't made contributions though. Don started at a young age, I have a 1954 NACA research paper on muffler design that he was involved in, which references a previous NACA muffler research paper from 1949. Once the higher math was 'dumbed down' for me, it gave me a keen insight into resonant pipe theory. The test rig was driven by a short TQWT loaded 15", but it doesn't say what brand/model was used and the picture isn't clear enough to tell.

Anyway, fig. 9-10 is the basic layout I'm referring to. I'm no expert, just a jack-o-trades, master of none, though with a fairly wide range of experience (the consequence of being way too curious), including converting a neighbor's basement into a ~LEDE multi-channel music/HT back when Fosgate controllers were the rage, but whether I can get you 'right' without you doing some measuring/tweaking remains to be seen.

Again though, until the rectangular room's dims are 'nailed down'...........

GM