Home made cabinets require drivers and x-over. Any recommendations?

[aim]

I built a pair of cabinets based on a design taken from the Eminence loudspeaker design book (since lost). These cabinets have been sitting around for several years now acting as little more than a table. Now I believe the time is right to finish them off. Problem is that I lack the knowledge and experience to design the x-over and select the correct bass driver and high frequency driver. I’m hoping that someone will help me make the right decision first time round.

I’ve only a basic understanding of circuit design but I can solder components if I’m given detailed component specifications and a circuit diagram.

The cabinets were designed to take a 15”driver and a horn for the high frequencies. They have the following dimensions: -

H31”
D17.5”
W22.5”

I hope to combine these with an existing pair of 18”, 500w, 8 ohm, per channel single scoop bins (H31” D27.5” W24”) to provide a lovely full range 2K system. I have a Behringer Europower EP2500 amp that I believe will run this proposed system nicely @ 4 ohms or even better @ 2 ohms. That is if I can match the impedance of the speakers with some nice wiring.

I was thinking of Eminence or Fane components and possibly making a 2 way X-over. Has anyone experience in PA speaker design and construction who might be able to provide recommendation for components and if applicable x-over circuit diagram to match?

I’m happy to purchase x-overs but I’m always confused that, generally, the power handling seems far less than that of the drivers available today. For example, the Eminence website indicates that they manufacture drivers that are over 1k but all their x-overs are rated a 400w….Seems odd to me.

I’ll be needing detailed specifications,

Thanks in advance!

[aim]

Wow, I'm shocked that this isn't getting any replies. This being such an open ended question I thought everyone would have a recommendation or two!

[sreten]

Hi,

Point your browser towards Studiospares in the
UK and buy the parts for one of their systems.

1kW drivers, yeah right ... see

http://sound.westhost.com/project117.htm

and

http://sound.westhost.com/articles/pwr-vs-eff.htm

/sreten.

[aim]

Thanks for your advice sreten, the information from sound.westhost.com was very informative indeed. Although it would would seem that all manufacturers would utilise the maximum output efficiency when rating their drivers a bit like Peak Music Power compared to AES or RMS. So checking output efficiency, sensitivity, impedance and frequency response chart should be enough to choose a decent driver.

Your recommendation, Studiospares, don't have much of a parts selection on-line i.e. no compnent kits or detailed advice as I require. I've ordered a catalogue and will look further though.

On a separate note I hope to configure a balanced system with 500w per speaker (4 speakers including my scoops) to 2 or 4 Ohms per channel to suit my EP2500 amp. I worry that this won't be possible if I look at these new speakers separately to my existing scoops.

[sreten]

Hi,

On page 75 of the catalogue they have the chassis speakers for
their completely built products. I thought they also sold the c/o's
but I cannot see those, perhaps you need to enquire.

/sreten.

[aim]

Come on guys, any more advice?

There are so many options, this is a fresh build!

Thanks

[wg_ski]

Originally posted by aim
Wow, I'm shocked that this isn't getting any replies. This being such an open ended question I thought everyone would have a recommendation or two!

An open ended question that not a lot of us would touch with a 10 foot pole. Getting a 15"/1" PA to sound like anything isn't trivial, and I'd suspect that anyone who has done it isn't giving away any of their secrets.

If the cabs aren't committed to a 15"/1" yet, you may think about a 15"/8"/1", or 2x12, or go to a 2" (Selenium D3305) if you want to stay 2 way with a 15". A 15/8/1 is at least WORKABLE with a stock x/o with an L pad on the highs.

[Cloth Ears]

Originally posted by aim
Wow, I'm shocked that this isn't getting any replies. This being such an open ended question I thought everyone would have a recommendation or two!

The problem is that you're putting the cart before the horse. You decide on your drivers and then build the cabinet. You may be able to get something to "fit", but it'll be more by luck than design.

My suggestion, find another copy of that book that you lost and buy the correct drivers for your cabinet.

The EP2500 is quite a good PA amp, and it'll take a lot of punishment (for the price). I've got one, but I'm not going to use it for anything other than a subwoofer (and this house is too small). You may want to look for a good amplifier, as your highs will probably sound bad with this amp...

[Brett]

Originally posted by aim
I
The cabinets were designed to take a 15”driver and a horn for the high frequencies. They have the following dimensions: -

H31”
D17.5”
W22.5”

What is the internal volume of the box? Are there any ports in place (dimensions)? What size is the horn cutout? What sort of budget?

[aim]

Originally posted by wg_ski


An open ended question that not a lot of us would touch with a 10 foot pole. Getting a 15"/1" PA to sound like anything isn't trivial, and I'd suspect that anyone who has done it isn't giving away any of their secrets.

If the cabs aren't committed to a 15"/1" yet, you may think about a 15"/8"/1", or 2x12, or go to a 2" (Selenium D3305) if you want to stay 2 way with a 15". A 15/8/1 is at least WORKABLE with a stock x/o with an L pad on the highs.

wg ski…A fair point but that’s why I came here. Looking at the posts there's a lot of knowledge shared on complicated subjects.

With regards to modifying the design to include more drivers, I’d prefer to stick to the original specification of just a 2 way system. I was also under the impression that this would be easier to complete due to less parameters in the equation.

Originally posted by Cloth Ears


The problem is that you're putting the cart before the horse. You decide on your drivers and then build the cabinet. You may be able to get something to "fit", but it'll be more by luck than design.

My suggestion, find another copy of that book that you lost and buy the correct drivers for your cabinet.

The EP2500 is quite a good PA amp, and it'll take a lot of punishment (for the price). I've got one, but I'm not going to use it for anything other than a subwoofer (and this house is too small). You may want to look for a good amplifier, as your highs will probably sound bad with this amp...

cloth ears… I see where you’re going but these cabs were built from a professional design, and finished to a high standard even if I do say so myself . Although I’m well aware of the differences between all the available 15” drivers, I believe that there must be similar drivers available today if not better. In fact, if my memory serves me well, the book suggested a range of suitable drivers.

With regards to the EP2500 amp, I bet you’re right but this is a PA system that will probably be used in combination with other, smaller, sound systems to provide more clarity in the mid/high end. I must admit that I was impressed with the build quality of the EP2500 for only £220! There’s no way you could get such an amp for that price a few years back.

However, after looking in more detail at the EP2500 specifications it does appear that it will only run 1 set of 450w per channel speakers (seems that @ 20 – 20Khz it’ll only do 450w @ 8ohms). So, I’ll need to buy another one to run both my scoops and these new builds. If you can think of an alternative amp with better frequency response for a similar price, I’d defiantly like to hear about it.

Originally posted by Brett

What is the internal volume of the box? Are there any ports in place (dimensions)? What size is the horn cutout? What sort of budget?

Brett… I believe the volume is as follows: -
12 206.25 cubic inch or 200 024.599 95 cubic centimeter (they're big!)
The book indicated that these are to be sealed enclosures and no cutouts have been made so far. My budget is going to be in the £300 mark to fix out both speakers; I’m sure I can get a decent setup for this (well I hope)

Thanks to all of you for your help so far, if we can get to an agreement on what to choose (drivers, horns and x-overs) I’ll be sure to send a picture and comment on the sound quality.