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AttilaM 29th December 2011 01:59 AM

Cloning IDS-25s
Hey everyone.

I'm doing my best to clone a pair of IDS-25s. This isn't a "I want the most bang for my buck" project, it's purely an attempt to get as close to an actual pair of them, without the amazing pricetag. I find the design really interesting.

So, my experience in building is pretty limited, and hopefully somebody can help me out with a few questions:

1) Grouping. Are the speakers just run in 5 groups of 5 on each side? Can I run them like this? Am I missing something important?

2) Exact box dimentions. Does anyone know this?

3) What's in the boxes? Are they stuffed? With what?

4) What is a reasonable amp to use to drive them?

I'm a cabinet maker, and am doing this as part of a refurb of my bedroom. Will be finished by the second week of January.

Thanks in advance!

planet10 29th December 2011 02:35 AM


Originally Posted by AttilaM (Post 2837814)
1) Grouping. Are the speakers just run in 5 groups of 5 on each side?

That makes sense. I'd even tend towards building 5 stackable boxes.


2) Exact box dimentions. Does anyone know this?
3) What's in the boxes? Are they stuffed? With what?
4) What is a reasonable amp to use to drive them?
Depends on the driver you choose x 3.

The tricky part of the electronics is the EQ.

The drivers used are a VIFA 3" FR (actually classed as a midrange).

IMHO you can get small FRs as good for less money.


18Hurts 29th December 2011 02:47 AM

I would get the specs on the speakers then make the boxes larger so less EQ is required. On the IDS pages, the engineer states the boxes are rather small for bass loading.

From what I remember, they are wired 5 series/5 parallel with no exotic wiring schemes. The only interesting thing I would do with the cabinet is put all the parallel speakers in their own sealed portion (5 segments).

You can stuff speakers with poly fill (pick up pillow fill at a fabric shop) how much you stuff it is up to you. Generally I use about half a kilo every 30 cubic liters (a pound per cubic foot) you can use more, you can use less.

The speaker boxes are supposed to be as close as the ceiling and floor as possible, if you run 25 of these speakers

Dayton ND90-8 3-1/2" Aluminum Cone Full-Range Driver 8 Ohm 290-210

The array will be a minimum of 222.25 cm tall (87.5 inches) I believe he used those Daytons listed above, you have the option to use the Vifas or other 3" full ranges etc. Don't forget that EQ--the magic in the box.

Those speakers have a Vas of 0.05 cu. ft. (1.415 cubic liters) so pick how large you want to go sealed. I'd say to pack them in tight, make them as short as possible then put a base on the speaker to get them closer to the ceiling.

The main thing is EQ for those things--they need that as priority #1. As far as how much power you require, they "average" 94dB at one watt so are quite efficient--you don't "need" massive amps. They will take a lot of power if you have it available. All depends on how large your room, what music you listen to and will subwoofers be involved. A traditional home theater receiver should give you plenty of output--make sure it has the ability to patch in the EQ.

As far as exact box numbers--you can determine that from the speaker spec sheets and how large you choose a sealed enclosure. Do you want them to be a rectangle, 5 sided or ???

Tom V 29th December 2011 04:37 AM

This link is part of the reviews of the ND90-8 at Parts Express: The Murphy Corner-Line-Array Home Page

Seems to be a similar (identical?) concept to the IDS-25's, and all worked out including equalizations.


norman bates 29th December 2011 05:35 AM

I'd use the tc9 (similar driver with copper cap but a paper cone, like $10 each), but you need what, 50 of them ?
He used a version of the tg9 (fiberglass).

And you need a bunch of eq, maybe 12 or so db in the high end, then baffle step, and a bunch of eq to go low also. So the black box will make or break this project.

I assume you've heard such a beast. It is a tall sound, or a wall of sound.

Check out all of the kuze array, especially the pre/post graphs and the listening comments (you have to wadw through them). Good party speakers, but a tall image (if you don't mind it).

Speaker Projects Gallery,Speaker Design Goals, Project Materials, Enclosure Assembly, Speaker Project Photos and More, Submitted By Parts Express Customers.


AttilaM 29th December 2011 03:30 PM

I actually have 50 of (what I believe is) the same drivers Russel used in the IDS-25s. Vifa TG9FD10-04 3.5 It's what makes the project interesting, IMHO. If I do everything right, I should end up with a sound-alike for a $18000 set of speakers.

For the box sizes, I'll use the external mesurements Russel provides on his page, and assume he went with 16mm MDF and is telling the truth. Four sided trapazoid boxs. Except for the bases, which look like 32mm. I asked just in case somebody had some inside info. The trapazoid shape makes the joins annoying to do, but FFS, I'm a cabinet maker. ;)

I know this may not be exactly aligned with the DIY ethos, as I am just stealing somebody elses design.

Thanks for the info on stuffing. Appreciated.

I've never listened to anything on that scale, but I'll curious to see in an honest a/b test with the current (ducks for cover) Bose 601s on my walls. Surely if they're good enough to warrant the pice tag, even a cloth-eared git who thinks 601s sound good should be impressed.

Five stackable boxes would mean there would be gaps between drivers in a few places, unless I cut a bit away from the bottom of each box for the spider. Which sounds like too much work, and steps away from my "clone what RR did" conecpt.

Having not heard a line array before, it sounded like a fun thing to build. The small footprint is appealing, and the theory just feels "right". Also after the outlay for the drivers, the cost in time and material is neglegable when tacked onto everthing else I'm building for the room. This way I can spray the speakers in the same white/black motif I'm for the rest of the furnature. Nice looking, and hopefully good sound.

I was considering taking the "dead" space in a corner unit I'm building, (the empty space mesures 660 x 812 x 800mm, 15 odd cubic feet if you're in the US) and installing some sort of honest subwoofer, using an 18" driver or similar. But to me that kinda destroys the purity of the design and the idea. The point seems to be that you can get good bass without resorting to that. No crossover, no sound coming from different places. Still, I can always cut a hole and slap one in at some point in the future. If just to watch things shake across my desk.

Thanks for all your help thus far. It's very appreicated. I start cutting for this job on Jan 2, and should be done by the 14th. (I have a holiday away in the middle there.) Thanks again.

norman bates 30th December 2011 03:11 AM

If no baffle step, I usually have luck running a subwoofer (passive) at the same time. You don't gain as much due to lack of a crossover blocking low frequencies to the voice drivers, but you can back off the bass boost, or use some bass cut, and you keep the tg9's as pure as you can (not including booster box anyway).

Depending on your music, sure run a sub.

Many like the array from comments. The people that didn't were followers or the 2 or 3-way arrays, usually the people with the ribbon tweets.

Wiring will be a pain, make sure to keep checking with a battery so all the drivers move out at the same time.

I had a lot of fun with one of my first setups, a Kustom pa speaker column (6 x 8" with whizzers). Yea you had to play with the tone controls, but dynamics were great.

35 x 3.5" cone area I think was around the area of an 18" speaker, but you have 3mm xmax. That is still a lot of noise :-)


yepvegas 2nd July 2012 09:18 PM

Did you build the speakers. What is in the EQ box that makes it all work. To be honest the crossover aspects of the project go right over my head. I would like to build a line array, the part that confuses my is the crossover. If you use a series of full range drives why do you need a crossover at all. I have been reading and lurking around but some aspects of the diy audio elude me.

If you did build your project do you have pictures? How do you like them?

Scottmoose 2nd July 2012 09:38 PM

There isn't any crossover in the IDS25. There is however substantial EQ to boost the low end ~flat to 30Hz and to increase the top end above about 1.5KHz. Note that the gain (often, but not invariably) provided by arrays does not apply across the whole frequency band; it gradually rolls off until total sensitivity becomes ~that of a single drive unit. Eq shouldn't be too difficult to achieve; there are several Behringer products that could be used; ditto the minidsp etc.

A few people have built ~equivalents to the IDS-25; there's a couple of examples on this thread:

yepvegas 5th July 2012 07:34 PM

Thank you for the information

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