Ideas for front mains

**Mongrel714** · **05-28-07, 02:59 AM**

Hey guys, been working on a design for a sub which I posted over in the soundsplinter thread under optimum enclosure, and here is my first idea on my mains, let me know what you think, will this design sound good, figuring the enclosure size, port size etc. I'm thinking aprox. 48" tall, (38" not counting the metal stand) and 24"to 30" wide, and 17" deep, initially will be loaded with the Dayton aluminum cone drivers, I'll have to study up on X-overs also. thanks everyone!
Added a couple more traditional designs.

**Randall R. Dibble** · **05-28-07, 08:02 PM**

Comb filtering and phase issues galore!

Research what these concepts mean and you understand why line arrays have become so popular.

Sound doesn't behave in the ways we commonly expect.

Sorry!

**drf** · **05-29-07, 05:24 AM**

They look fantastic, but I would say from an accoustical point of view they are too complicated. I would definately be keeping the curves and flow, but try to reduce the number of drivers and keep them in line and on one flat baffle. If this makes sense.

Cheers

DrF

**JCD** · **05-29-07, 12:56 PM**

I'm with the other guys.. looks cool, but there are a ton of issues with the accoustics.

haven't even looked at the internal volume issue either -- you should plug your driver's T/S info into something like WinISD to see if you've got the right volume and port size.

JCD

**Mongrel714** · **05-29-07, 04:56 PM**

Thanks for the info guys! maybe If I reduce the amount of drivers and do a rectangular enclosure inside the curved one to even things out, I was looking at the 5 1/4" and the 7" drivers for this, if I reduce the
5 1/4" s to 2 or 3 and lose one of the 7" s and a tweeter,would that be a better set up?
When I nail down the number of drivers Ill figure the enclosure volume and try to learn alittle about the X-overs with some help from you guys! Thanks a ton!!

**Sonnie** · **05-29-07, 05:29 PM**

I have to say that is some serious creativity there... although it would probably sound worse than my singing (believe me... that's pretty bad...

)

**JCD** · **05-29-07, 07:14 PM**

Please take this for what it's worth -- just the advice of someone who's dabbled in DIY, but will never claim to be an expert.

First, the biggest issue to me isn't the number of drivers, rather it's the orientation of the drivers. You'll want them in a vertical line. My general rule of thumb is that, all other things being equal, more drivers is better. The main reasons for this vertical orientation have been listed above already.

If you decide to go with the curved box, I don't think you need to worry so much about building a rectangular box for the interior volume unless the speaker is really shallow. That being said, I'm not entirely sure if there aren't any issues involved -- resonance issues would be something to investigate. Just for reference, of the "normal" shapes, sphere's are actually the "best" enclosures -- and I think pyramids of a minimum angle come in second with rectangular boxes third.

One other issue you'll need to investigate with a curved enclosure is the baffle step compensation you'll need for your speaker. Edge diffraction may be another issue to look into, but probably not more than a "normal" speaker. Finally, just building an enclosure like that is going to be pretty difficult to make look good. Not saying it can't be done, but I know I don't have the skills to pull that off.

The last issue I want to address is the crossover. Building a two way crossover properly is difficult/time consuming/potentially costly. It requires a lot testing, measuring, etc. Going with a three way crossover, especially for a beginner, is nigh impossible. Unless, of course, you go with an active crossover -- which, of course, means you'll need to buy a lot more amps. I'm building a 2 way line array right now and I'm WAY too chicken to try and design a proper crossover for this speaker (I'm going active). Like I said above, I'm not an expert, but I've been dabbling in this DIY stuff for a little while, but this area is way to technical for me.

And please don't assume I'm trying to counsel you out of designing your speakers from the ground up --- I just would hate for you to spend a lot of money on a lot of drivers/crossover parts and spend a lot of time building a speaker only to discover you don't like the end result. I really enjoy the whole process and would LOVE for you to try your design -- I just wanted you to be aware of some of the issues you will need to address if you want it to sound as good as it looks.

JCD

**JCD** · **05-29-07, 07:37 PM**

One other issue I thought I'd bring up was your driver selection. I didn't actually look at the specs, but it looks like you may have too much overlap and not enough coverage with those drivers. I'd expect something in a three way design to go with a tweeter, a 4-5" mid and a 10-12" bass driver. From what I've gathered, look at the FR charts for the drivers. What I'd look for is for the drivers to have a minimum of 2 octaves where they overlap on a (relatively) flat response.

For example, if you have a tweeter that has a frequency range of, say, 2,000Hz-25,000Hz, I'd like to find a mid that is flat up to 8,000Hz and then pick a crossover of 4,000hz.

Just more stuff for you to ponder..

JCD

**Mongrel714** · **05-30-07, 04:46 AM**

Quote:

Sonnie wrote:

I have to say that is some serious creativity there... although it would probably sound worse than my singing (believe me... that's pretty bad...

)

LOL,`come on, you couldn't be that bad

**Mongrel714** · **05-30-07, 05:01 AM**

Hmm, Some serious issues here, but i'm not ready to give up yet, I'll look up the specs on the drivers tonight, (it's 6 am, I'm off to work), and go back to the drawing board on driver placement, As far as x-over, is there no kit out there that would fit the bill? (I'm totally un schooled in this) I know in car audio it was fairly easy to buy a cross over and match it up to a three way system and get a good result, Man, if this is so problematic, then my center channel design is going to be a night mare! Talk to you guys later!

**Mongrel714** · **05-30-07, 09:38 PM**

Did some redesigning, box size would be roughley 48" high, 20" wide, and 10-15" deep, Been reading on the line arrays and I'm understanding more now, thanks thylantyr! well gots to get some shuteye, see ya's! opp's my port moved in the drawing, sorry.

**aceinc** · **05-31-07, 11:28 PM**

Much better I think, but I believe you will want to scrunch the tweets together (maybe even trim the flanges flat on the top & bottom), and make mirrored pair cabinets, with the cabinet shown being the right hand cabinet. Also try to keep the center of the tweets at ear height.

Paul

**JCD** · **06-01-07, 11:45 AM**

Some thoughts on the latest design..

I like the line up of the tweeters and mids -- but I agree, I'd scrunch them together as much as possible
Consider ribbon tweeters -- their dispersal pattern is ideal for line arrays
Maybe also consider more mids and less tweeters. Tweeters typically have a higher SPL -- plus if you're going with a ribbon, they're more expensive.
You may not need the woofer -- it's possible to find a mid that's going low enough that it won't be necessary. Also, with that many woofers, you could probably EQ the bottom part to get the bass your looking for -- you get a lot of headroom when you've got a lot of drivers like that, so the drivers collectively could manage to go lower without seriously degrading the sound
Re: Crossovers --you can buy a pre-fab'd crossover; however, this crossover doesn't take into account the electrical properties of the drivers themselves. You might want to consider reading this as a starter.
And if you can pull off that enclosure design.. that will be wickedly cool!

JCD

**drf** · **06-02-07, 04:47 PM**

To pick out some points JCD made,

you really only need half if not less the number of tweeters than you have mids/woofers due to the Intrinsic nature of accoustics and transducers/crossovers.

If you build that design please post detailed plans and photos, I am interested in following this and maybe even building something similar.

**Mongrel714** · **06-02-07, 08:34 PM**

I sure will do pics and notes, I am checking into some alernative building materials due to the curve involved, we do alot of marine condtruction with a material called "Starboard" which is a very strong extruded resin that comes in colors, cuts and screws together just like plywood, but is very expensive, I probably can get it at cost though, as a 4x8 colored 3/4" sheet is nearly $300 retail, a friend made a dual 12" sub enclosure for his car with good results.
So, I think I'll try 3 ribbon tweets per side, drop the big driver, and see how it goes, we can always add more tweeters later if needed,
Let me know what you all think of the Starboard. later.

**JCD** · **06-04-07, 11:23 AM**

Quote:

Mongrel714 wrote:

I sure will do pics and notes, I am checking into some alernative building materials due to the curve involved, we do alot of marine condtruction with a material called "Starboard" which is a very strong extruded resin that comes in colors, cuts and screws together just like plywood, but is very expensive, I probably can get it at cost though, as a 4x8 colored 3/4" sheet is nearly $300 retail, a friend made a dual 12" sub enclosure for his car with good results.
So, I think I'll try 3 ribbon tweets per side, drop the big driver, and see how it goes, we can always add more tweeters later if needed,
Let me know what you all think of the Starboard. later.

I can't wait! I think it's great you're gonna forward with your project.

I also like it that you're leaning towards ribbons. I would have gone that route within my line array project except I wanted to work with a strict budget. I ended up going with a horn tweeter. That would be the other option I think you should consider should the ribbon's be too much. The other issue with the tweeters that I've heard -- that I have NOTHING to back it up with -- is that you should go with 1, or 3 or more -- just not two. I have been told that there is some really weird stuff that goes on when you have 2 tweeters as opposed to 1 or 3 or 4 or...

As for the resin -- not having seen/touched/etc it, I'd be inclined to say it should work fine. My understanding is you want to find something that is stiff, i.e., won't flex. If this resin doesn't flex, you should be good. I've heard concrete actually makes a very fine cabinent box from an accoustic standpoint. It's just difficult to "build" and can be a little heavy..

Anyway, there's my 2cents.

JCD

**drf** · **06-05-07, 04:09 AM**

Quote:

JCD wrote:

The other issue with the tweeters that I've heard -- that I have NOTHING to back it up with -- is that you should go with 1, or 3 or more -- just not two. I have been told that there is some really weird stuff that goes on when you have 2 tweeters as opposed to 1 or 3 or 4 or...

I heard the same thing many years ago, but buggered if i can remember where or why

It may simply be an old wives tale about comb filtering,

.

Mongrel, have you got a plan view for this enclosure? I would love to see it.

**Mongrel714** · **06-05-07, 11:32 AM**

Thanks guys, great to see such enthusiasm for this project, really gets me fired up, I will be finalizing the plans and getting them together over the next week or so, then begging for help with the specs, lol, I really have to work on learning the software,

thanks again for the inspiration!

**Mongrel714** · **06-05-07, 07:31 PM**

Ok guys, the resin board is out, $200 a sheet my cost, WHEW!!!!!, So now my plan is to use some 3/4" Birch, and for thoses of you with kids that skateboard will be familier with this, On the interior side, make 1/4" deep cuts horizontily spaced 1-1 1/2" all the way up the curved part of the enclosure, then assemble the enclosure, fill the relief cuts with wood filler or auto body filler, then coat the interior with fiberglass resin to keep it in place, which probably would not be a problem unless you were doing a sub enclosure this way, but I would want to be sure, I will get some more info together soon for this, This is making me want to get weird with my sub enclosure, but.. Nah we'll stay safe with that one, Talk to ya later guys!

**JCD** · **06-06-07, 01:34 PM**

Wow, $200/sheet is a bit pricey!

Well, I for one can't wait for you to document the process!

JCD

**Mongrel714** · **06-06-07, 09:36 PM**

thylantyr, Very cool Song! and a great name,

I'm a fan of all kinds of music, but the majority of my old road bands were METAL!! so thank you for that.
sorry guys no plans yet, still working on them, the Florida sun is taking its toll on me and slowing me down, but, I did bring my amp rack home for a test fit, you can see the Onkyo reciever on the bottom, up top I'll mount the QSC RMX1450, the BFD, and have room for one more unit yet to be determined, There is 3" of space on the vent above the reciever, Cheers all.

**Mongrel714** · **06-06-07, 10:06 PM**

Hey guys, give me your thoughts on these,

http://www.mcminone.com/product.asp?...duct_id=53-840
!!
And if you would, please give me some ideas on drivers that have frequency ranges that would work with this tweeter, Keeping in mind I'de love to use the aluminum cone Daytons for the look, but its not a deal breaker, Good night!

**Mongrel714** · **06-07-07, 04:23 AM**

If I used the PT2B planer @ 2000-26.000 Hz, What freq mid driver should I use?

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