Need help choosing midbass drivers for line array.

[svbear]

Hi,

I need help in choosing some midbass drivers to go with some tweeters I won on ebay for a line array speaker box.

This is the tweeter - stryke sa-tw1 soft dome - The 1050hz Fs allows it to be used in systems with Xover points as low as 2KHz. It is 90dB efficient, 1w/1m.

Now the possible midbass drivers (all from partsexpress unless someone know where to get them cheap in Canada);

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=299-432 VIFA BC11BG07-06 4-1/2" JBL MIDBASS 6 OHM
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=299-495 VIFA 4.5" JBL MIDBASS
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=299-433 VIFA BC11SG06-12 4-1/2" JBL MIDBASS SHIELDED 12 OHM
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=299-492 VIFA TC11MG-07-04 4.5" INFINITY WOOFER
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=299-493 VIFA TC18WG-15-08 7" INFINITY WOOFER

I really need help since I am a fresh newbe.

Also, how many would you recommend (I won 36 tweeters - so anything is possible).
And what ratio config would anyone recommend.
Or even crossover points/slopes.

Any design help is greatly apreciated and would be accredited as a God when I post my final creation.

Thanks,

Adrian

 

[Cal Weldon]

Hi.

I noticed you didn't have these on the list:
Vifa line array driver

Is it because they are a little more pricey? They are a dandy little driver for line arrays.

I used them to replace the woofers in the old RS Minimus 7's. They can take quite a bit and come back for more.

How many? 8 per side if you want a 4 ohm load or 16 if you want 8 ohm. Personnaly I'd go for 16 if you have the room. Mind you I'm not paying for them.

And no such thing as cheap in Canada, at least not on the west coast

Cal

 

[GM]

I really need help since I am a fresh newbe.

Then you are probably in over your head. I recommend you read/study this before spending any more time/$$ on driver selection/design: http://www.audiodiycentral.com/resource/pdf/nflawp.pdf

GM

 

[svbear]

Hey Cal, it's a nice woofer, just my budget is a bit tighter. For the same money, I can get 3 to 4 of the other drivers. It makes it a bit better to swallow when your looking at 16/side or more drivers.

Most likely I will go with 8 ohms to keep these more universal for different receivers.

Hey GM, I did spend the whole day reading the articles. A lot to comprehend in a short time. I had to make the decision today whether or not to bid on the tweeters.

What I'm after is for music only, not HT. I want to try out the larger soundstage. So I can move around and not have to stay in the sweet spot the whole time.

Some things I did notice (and if some one can say or nay on);

1) Tweeters are position to the inside of the baffle as close to the edge as possible.
2) To really get the line array effect, you need more than 4 drivers height per side.
3) For the baffle, the narrower the better for imaging.
4) Perhaps have the option to power taper the array with a second set of banana plug inputs (which have an in line resistor to the lower and upper drivers).

How am I doing so far.

I just want to pick up the midbass' before the go off sale or out of stock.

Adrian

 

[BillFitzmaurice]

Back to Square One

Before considering the midbass units you have to revisit your tweeters. These are not really suitable for a line array. The frame around the radiating planes of these looks to be at least an inch and a half wide; that being the case the minimum distance between the radiating planes would be 3 inches. The highest frequency to which your tweeters could possibly integrate would be 4500 Hz, and if the frames are wider than that the frequency would drop accordingly. I'd see if you could swap them off for a more appropriate tweeter if you want to go line arrray.

 

[svbear]

Hey Bill, you're right on the money about that.

The company lists a crossover design that looks to me to be about 3500Hz at 18db with a top end filter.

After reading Jim's guide a bit more indepth, I'm surmising that I will have to trim the flanges a bit.
I am trying to call the manufacture to get the size of the back magnet and how close they could possible be mounted.
Hopefully I can trim them down enough to get ~2 to ~2.5" c-t-c spacing.
Worst case, I can remove the trim ring, and make a new one piece trim ring for all the tweeters together out of say plexiglass.

If I don't end up using all the tweeters, is there a way to use them for a tripolar rear surround?