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Building a Dinner Theater w/ DIY Speakers, Subs, etc... - Page 3

post #61 of 585
That 5x5 birch is supposed to be the highest quality birch...well except for marine grade plywoods, but I don't know how they fair sonically. I'm sure just fine.

MDF has the advantage in deadness by a small amount over plywood due to weight/inertness.
post #62 of 585
I actually like working with MDF. My 4PI's cabinets with sanding primer.

post #63 of 585
i bought 6 sheets of 13-ply 5x5 Baltic Birch @ $45 each to build my speakers and subs, and i'll not use anything else.

but again, some here are also big fans of MDF.
post #64 of 585
Thread Starter 

I saw your build thread. You did some excellent work with MDF. I suppose, in the end, I am more comfortable using the Baltic Birch. I have never really worked with MDF before and do not wish to go through that learning curve on my mains.
post #65 of 585
Thanks, I like the way it reacts to the router particularly the round over bits. The cabinets do get heavy.
post #66 of 585
Thread Starter 
Sorry I have been away so long...been plugging away on Winery business.

Click Here to see the build thread on our Facebook page.

Now, on to my questions; As we get closer to the completion of our project, it is becoming increasingly important to finalize the type, quantity, and location for all of the speakers that will comprise the dinner theater and stage sound. What I am currently proposing is depicted below the best I can. I realize that measurement is the best way to determine the suitability of placement, but we are restricted in that regard and so must do our best using theory.

1. Since we are limited on sub placement, should I increase the number of F20s being employed, such as going with 3 on each side of the fireplace pointed directly at the audience for a total of 6? Perhaps build the further most north and south F20s with the horn going out of the side in a 6 sub configuration, 1 pointing each north and south with the other 4 pointing at the audience? I could easily widen the wall that sticks into the room to accommodate them. I figure if I don't have much say where they go, perhaps I can take the "carpet bombing" route and just go bigger.

2. Should I use the F20 subs on the west wall for the lower frequencies in conjunction with the two stage 4pis when the subs are not being used for theater duty? Do I need to perhaps incorporate two smaller subs on the stage for that purpose? Do both?
post #67 of 585
thats some impressive work thus far!! Do you already have the drivers?
post #68 of 585
Thread Starter 
Originally Posted by beastaudio View Post

thats some impressive work thus far!! Do you already have the drivers?

We will wait until all of the enclosures are finished before purchasing the drivers. Wayne said to give him at least a few weeks lead time to get that many components at once. I do have a single Reference HF for the F20, as I had to buy one to know where the screw holes would go.

I am building the third 4pi right now. (I "set aside" the first 4pi I built using Arauco, as it did not turn out great, and I used too many screws. All of the speakers you see in the picture above were made with 5' x 5' 18mm baltic birch. This stuff truly is the best.

The F20 was made with 7ply "oak" from Lowes; but it seemed like pretty decent wood for that application. The other three F20s will be the last cabinets I build, as I will be having ED out of Newton CNC the wood for me. I wish I had something to plug that F20 into so I could listen to it. I suppose I could drag it downstairs to my home theater and plug it into my 7.1, but I think it would only be getting about 100W from my amp. I should post a picture of the theater I built 5 years ago...it is actually pretty impressive (though it uses Polk Audio shelf speakers...though-be-it I recessed them into the wall).
post #69 of 585
In a 45x30 room, I'd cluster subs rather than spread them. Spread out subs makes for a good 'sweet area' in smaller rooms, but makes for lobing/interference problems in larger rooms higher in the sub freq range.

If you will use subs beneath the stage (do you need real low freq support for the stage?) I'd run them separately from the screen subs, to avoid interference issues.

Your room is at the border of the 'spread subs or not' debate. A little bigger, and I'd say cluster them, for sure. Smaller, and I'd say spread them for a nice sweet spot in the middle.

I say cluster them. Keep 4 beneath the screen, and 2 under the stage. Don't run all at once. In fact, if the stage will mainly be live music, use different subs that are more efficient from 30-40Hz on up.....but the F20s should do well there too.....

Also, one more thing: The L/R screen channels may need to be outside the area of the screen for good integration with the surround arrays.....something to think about, but not critical.

Point the surround array individual speakers at the 2/3rds point on the opposite end of the room. It doesn't always equal 45 degrees down-slope....

Each 'level' of surrounds (distance-wise) will require a delay so that sound coming from the mains and surrounds at the same time will hit listener's ears at the same time...at the differing distances.....

post #70 of 585
Originally Posted by dutchswan0311 View Post

On the first one, Lowes actually performed the 14 cuts @ $0.25 per cut lol. When I measured the panels at home, they actually did a pretty good job. A couple of panels are 1/32 - 1/16 long, but I think that should be within the tolerance range...don't you think? I will have to do the beveling myself, which I suppose the CNC would do as well. There is something to be said about precision.

My friend, I believe you dodged a bullet/got lucky here. I would not make a habit out of letting the big box store do any cutting, other than maybe halving a 4x8 if I didn't have a truck. Myself and others have had inaccuracies of 1/4"+ and I'm not picking on Lowes, this is the case with any store with a big panel saw of questionable condition and adjustment, used by a variety of employees.

sounds like you are probably done with needing cuts made but I thought I'd post this because I didn't want anyone reading this getting too much of a false send of security. I had a sub that ended up smaller than planned due to inaccurate, and out of square cuts.

Sweet place you have there, I'll have to check it out some time.
post #71 of 585
I was wondering what was going on with this winery.

Originally Posted by vitaminbass View Post

Myself and others have had inaccuracies of 1/4"+ and I'm not picking on Lowes

Ha, I'll pick on 'em. I had them cut a 4x8 in half so I could get it home. They didn't lock the blade and the sheet walked 4"...I got the sheet for half price.
post #72 of 585
DYI = Do Yourself In? Looking at the size of those things, it might be fitting! *Outch, the back!* Sorry, can't resist, I always think that when I see DYI!
post #73 of 585
Originally Posted by MKtheater View Post

BTW, I have 4 f-20's and had 2 dts-10's, I will measure and let you guys know which one does what better!!!

I am interested in this.
post #74 of 585
I'm not big on wine by any stretch of the imagination, but I sure would love to watch a movie there when it's all done.
post #75 of 585
Thread Starter 
Hello everyone!

After a few month hiatus from building speakers, I am finally back now that we are actually getting closer to that portion of our project. I always research things way in advance so that I can be prepared for any eventuality, and the winery's sound was no exception. I have only one F20 built, four 1pis, and two 4pis. I need to build a total of at least ten 1pis, five 4pis, and four F20s. I finally purchased a large heavy duty table saw to finish up these speakers, and am working on the third 4pi today. I have been working on finishing up the actual winery's exterior, and am now focusing on the inside, so I will start to update this thread now that I am back to it.

Below is a before and after picture of the outside of the winery. We just had the new roof installed, and the stone people will come out and completely stone the exterior in two weeks.


post #76 of 585
Very nice looking. Wish I were local to you when it's all completed.
post #77 of 585
Yeah, that would be an awesome place to check out sometime. It may have been mentioned earlier in the thread, but where are you growing the grapes at, and who is your brew master?
post #78 of 585
Originally Posted by dutchswan0311 View Post

.... I ... am working on the third 4pi today..

You'd save a lot of time if you built all the speakers of each type at once. Since most of the time is spend doing "setup" and little actually cutting wood you'll gain a lot of efficiency.

The winery is looking great. My ancestors settled in NM in 1864 to set up a winery in the Rio Grande Valley. My great grandmother ended up torching the vineyards to keep her sons from becoming alcoholics. All their presses and stuff is in a museum here in ABQ.
post #79 of 585
Thread Starter 
We are only a winery at this point. We purchase grapes from local Iowa vineyards, and the juice from these grapes with juice we purchase from all over the world. Mym mother and father are the primary winemakers right now while my brother and I finish the construction of the new location. It truly is a family business. Once we move to the new location, the four of us will all be making the wine.

With regard to making all of the same speakers first; while a good idea for work efficiency, it works better to go back and forth in an effort to maximize the dimensions of the plywood being used, not to mention I get bored easily ;-). I will be making the F20s all at once though.
post #80 of 585
Thread Starter 
How much of a problem is the 2,000 sq ft of hardwood flooring going to present for acoustics?
post #81 of 585
Thread Starter 
I will soon be building the dinner theater's baffle wall and need to "crap or get off the pot" with my final sound design. I KNOW that the correct answer is that I should hire someone to come out and measure, but if I had that kind of budget, I would not be building 23 speakers from scratch (I would buy them already built).

That said, I must use the expertise of those who are knowledgale on this forum in conjunction with all of the acoustical theory in order to determine what is needed. I have already built twelve 1pi speakers to be used for the theater's surround (I will post pictures later), and three 4pi speakers with all the upgrades for the LCR duty (again pictures are forthcoming).

I am now focused on what kind of subs to use, how many to make, and where to put them. So far, I have built only one F20 that will use the 390HF. My original plan was to use four F20s in the baffle wall under the 180" AT screen. In looking at Wayne's 3pi Subwoofer, it is also tuned to 20Hz but gets low passed at 200Hz (as opposed to 80Hz for the F20). The frequency response of the 3pi Sub is shown below (Sensitivity = 92dB, Max SPL = 115dB)

What I like about the F20 (well, what EVERYONE likes about the F20) is that the SPL is 106dB all the way down to 20Hz. So, now I am considering blending the two in the baffle wall. But, as I said; I need to decide soon as I will be building the baffle wall next week. I know people will say that I should place subs throughout the room and measure with a meter, but I am under a lot of pressure to keep everything out of sight. Below is an image of what I am considering right now. Is this too much? Not enough? Just right? It seems to be [visually] similar the speaker/sub placement at other commercial theaters. All qualified feedback is appreciated!

post #82 of 585
Thread Starter 
I received feedback from Wayne Parham saying that he didn't think the 3pi subs would play well with a horned sub due to delay on the horns. I would rather use only F20s than only 3pi subs because the 3pi subs just don't have the SPL at the lower frequencies that the F20s provide. So, it is still my plan to use four F20s grouped together under the screen pointing at the audience unless someone can offer a qualified opinion that is better.

That said, won't the F20s still be delayed in comparison to the 4pi LCR mains? Does this need to be compensated for? Also, will the F20s lowpassed at 80Hz and the 4pi extending down to 30Hz provide good transition, or should I find something to pick up the middle between say 60Hz to 200Hz? Thanks in advance for any feedback that comes my way.
post #83 of 585
You have a big room, so clustering subs is a good idea. Use all four F20s. Cross to the 4Pis at around 80-100Hz, a good AVR will do this for you. Use Room EQ Wizard to delay the 4 Pis with respect to the F20s. After that, the only thing left would be whether or not you will delay each surround pair individually or not, it may not be something that will be a deal breaker if you cannot.

An AVR that has a good auto setup function or adjustability should do the trick.

This is one of the threads I have been following for a while...

post #84 of 585
I KNOW that the correct answer is that I should hire someone to come out and measure, but if I had that kind of budget, I would not be building 23 speakers from scratch (I would buy them already built).

I'm in Australia, so can't help you there but someone offered to pay me to measure their system and room. I realised then that there was a demand and now offer it as a service locally. My suggestion - offer to pay someone to measure the system and help with integration. Someone who knows what they are doing. It's very worthwhile. If you can afford to renovate, I'm sure you can afford to spend enough to compensate someone for giving up their Saturday.


In theory you can get any kind of sub to work with other subs, although some combinations are definitely easier than others. You don't want to delay F20 at all, but instead delay the mains so the sub can catch up. This can also be true of direct radiators. With a horn you move the acoustic centre forward down the horn, but it will still probably have more delay due to around 4m of horn length. Any sub will require the mains to be delayed if you want it "time aligned."

Couple of points about the F20 - I've built one and simulated with different drivers. Seems to work best around 20 - 60 Hz, I doubt you will get good results running up to 80 Hz because it is a highly compromised horn. A full sized 20 Hz horn can be made to extend up high, but it must be far bigger. Also, the horn does not protect the driver well below about 25 Hz, so as a rule it's a good idea to run a high pass at that point. Probably around 2nd order.

How low do your mains go? I suspect you might have a bit of a gap between your mains and where the F20 would like to work. You don't really want a 12" low sensitivity sub in your situation. Perhaps a better solution is ported mains that can get down to 60 Hz, high pass at that point and F20 running up to 60 Hz. I'd be wanting to measure to ensure a good integration. Rythmik audio have an article about phase alignment of mains and subs, with either sealed or ported mains:

post #85 of 585
Thread Starter 
@Paul...I have already built three 4pi speakers for the mains. Frequency response with the JBL 2226h plus the B&C DE250 is 30Hz to 16kHz.
post #86 of 585
Thread Starter 
Below is what Wayne Parham had to say about the size of our room and if I should group the subs or spread them out. I haven't had a chance to crack out my dictionary yet, so most of what he said still reads like Greek to me.

"It's an acoustically small room. I mean, it's larger than your average living room, but still acoustically small for bass. I would define a room as being acoustically small if the Schroeder frequency falls within the passband, above 30Hz or so. Most homes it's around 200Hz. Yours isn't this high, of course, but it is still well up into the middle bass, between 60-80Hz, depending how you calculate it."
post #87 of 585
JBL 2226 is a high sensitivity 15 that doesn't like to go low. 30 Hz is highly optimistic. 200L box with 30 Hz tuning and it's -3db @ 80 Hz, or -6 db @ 30 Hz. A 60L box with that driver tuned to 50 Hz gets down to 60 Hz and could then be made to work with F20. That is probably more like what you have.
post #88 of 585
Thread Starter 
Originally Posted by paulspencer View Post

JBL 2226 is a high sensitivity 15 that doesn't like to go low. 30 Hz is highly optimistic. 200L box with 30 Hz tuning and it's -3db @ 80 Hz, or -6 db @ 30 Hz. A 60L box with that driver tuned to 50 Hz gets down to 60 Hz and could then be made to work with F20. That is probably more like what you have.

Here is the link to the measurements of the 4pi:

post #89 of 585
Confirms my suspicion. Shown as around 98 db on that chart, with 97 dB @ 100 Hz, and 3 dB down from that at 65 Hz. If your box is tuned low, then you could probably put in a high pass relatively low, perhaps 40 Hz and bring in F20 around 60 Hz or so. That's not a bad starting point. You are best to use measurements to take it from there.
post #90 of 585
Dutch, due to a lack of options, your only choice is to put the subs - all of them - in your front baffle wall. It would be better if you could disperse them throughout the room, but it doesn't sound like you can. HP them around 20-24hz and set the AVR's XO at 60hz. As paul already mentioned, that should get you off to a good start. You'll have a few hours of measuring a head of you, and that hardwood floor is not going to help anything!

Off topic, but do you know about mosquito pee? It's fermented lemon aid which utilizes old wine yeast. I'm going to be brewing some for this summer.
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