Custom Monitors

[serge instrumental]

I'd like to use some components from a medium to distant future. Here are the components: Aurasound NRT-18 (sub/woofer), ATC dome midrange, SLS Ribbon tweeter.

Theese are from my point of view some of the best speakers components soundwise speaking. Maybe the low/mid would the weakest point(a dip between 150/500Hz). Replacement for the midrange dome should be made about the same quality transducer! not an easy task! Could be a 6 inches or 8 inches for this range. Efficiency should be close betwenn components but not mandatory(Electronic Xovers) I would like to stay in a 3Way system.

Anyway I'd like to discuss with the Masters here about it(or anybody else)

Any suggestions would be welcome. Box size, soffit or not (prefer box for easiliy movin them around), Xover (electronic of preference) and cabinet dimensions/construction/materials/type(infinite or reflex).

Many thanks in advance!

[serge instrumental]

Nobody interested?

[barefoot]

Hey Serge!

Sorry for the late reply. AES was last week and I’ve been crazy busy these days. Looks like you have a quite a fancy system in mind!

Despite the extended bandwidth of the Aura, it is most definitely a subwoofer. I would not recommend trying to team it up with the ATC in a 3-way configuration. You definitely need 4-way with a woofer in between - something like the Scan Speak 18W/8545 or the equally outstanding (and more moderately priced) Usher 8945A. Two of these in sealed cabinets mated with the ATC would be fantastic!

As far as the tweeter goes, I am not a big fan of ribbons (planar magnetic in this case) for recording monitors. I think the off-axis characteristics are completely wrong and they particularly don’t team up well with wide dispersion midranges like the ATC. I would go with something more like the Accuton C2 12/6, C2 23/6, or the Hiquphon OWI.

Thomas

[serge instrumental]

Thanks Barefoot to chime in

My idea is to get all components to the equal efficienfy(and quality). True I haven't looked to the dispersion char. If efficiency is far from one component to the other(from what you suggest), dynamic range will suffer from one or more components. For me dynamic range is important. 88 db of efficiency is a bit low in a system based on Aurora sub and ATC midrange. Shure I don't want PA type of speakers, I need real low distortion sound. For me my goal is good efficiency and high quality sound(not an easy task!)

But the bar is opened!

I know that the Aurora is about 99Db/w/1 meter, the ATC are around 91 to 94Db(depending on the model)

The SLS is around 100Db(for a bad dispertion as you say)

Between 88Db and 99Db there is almost 11 Db efficiency difference. My question is: will it be costly to bring lower efficiency speaker to the same level of the higher efficiency speaker without sacrifiying headroom and distortion and without burning the voice coil of the lower efficiency speaker?
I know that I can lower the volume control for the sub(in an electronic XOver setup)

Again thanks for your interest

And for the last question is it possible to have a standard 3 or 4 way electronic Xover to do the job (lots of questions here!)

[serge instrumental]

Two of these in sealed cabinets mated with the ATC would be fantastic!


Thomas

You mean the woofer(s) in a separate sealed chamber, with the sub in a bass reflex enclosure, within the same cabinet?

When you say two of these, do you mean 2 woofers per box with the Aurora?

[serge instrumental]

Hope that Barefoot is not too busy

Thanks by the way for your suggestions about woofers and tweeters. I'll check how I could get theese in Quebec.

Lots of questions about cabinet making/dimensions/Xovers.

[barefoot]

Between 88Db and 99Db there is almost 11 Db efficiency difference. My question is: will it be costly to bring lower efficiency speaker to the same level of the higher efficiency speaker without sacrifiying headroom and distortion and without burning the voice coil of the lower efficiency speaker?

If you go fully active, then efficiency differences aren't a big concern. And there's no need for passive attenuators in series with the drivers. Of course, the lower efficiency tweeter will need to be driven harder in order to reach the same output level as the midrange. However, since you're using a dome midrange, you can afford a higher crossover frequency. Limiting the tweeter's low end extension will result in less power compression a high output levels.

Doubling up on the midbass drivers will also get you closer to the ATC efficiency. In any case, remember that high efficiency only helps reduce nonlinearities associated with power input. It doesn't necessarily increase maximum linear output. That is a function of the driver’s surface area and maximum linear excursion. Higher efficiency just means you will reach the maximum output at lower power levels.

[barefoot]

You mean the woofer(s) in a separate sealed chamber, with the sub in a bass reflex enclosure, within the same cabinet?

When you say two of these, do you mean 2 woofers per box with the Aurora?

Yes, two midbasses in sealed enclosures.

And personally I would also prefer to use the Aura NS18-992 in sealed box rather than the NRT-18 in a ported box.

[serge instrumental]

And personally I would also prefer to use the Aura NS18-992 in sealed box rather than the NRT-18 in a ported box.

I guess that the Aura NS18-992 (87DB/W/M) is a less efficient driver so a closer match between components.

But in all this woofer does it brings all the sound glory that the original NRT did?(with some sacrifice of efficiency)

[RyanC]

Serge-

I built my own monitors- there is alot more you will need then expensive drivers-

1st thing barefoot is absolutely right about the aura being a sub driver and i agree about the ribbons too. Ribbons might be good for Hifi one spot setup, but I am damn tired of telling my clients to sit down when the complain about the lack of HF (my system uses the fountek jp2's). Also it does not send an even sound into your room, wich results in lumpier playback because ribbons have very narrow vertical dispersion.

The reason the sensativity does not matter as much with an active setup is that you can simply set the gain on each drivers amp to match the overall system level. My tweets are 106db/1w1m and my mids are 90db 1w1m. Overall my system is very flat becase the amps for the mids are turned down by about 16dB. (Or you can get a less powerful amp but i would recomend that they share identical topologies).

I would however strongly recomend that you start with some cheaper components. I would recomend a copy of my current system an audax 8" aero gel, a TC 2 sub (the same as barfoots I believe) and then replace my fountek ribbons with accutons or whatever. I think that for a true full range speaker the ATC almost needs a 4 way system as noting but a high xmax sub will give you really great LF resoloution and while the ushers do sound good, I would choose a 3 way with a dome tweet and 2 cones (one high xmax) over a soft mid (like my system or barefoots). Also sealed boxes provide tighter cleaner bass and less phase shift at lower freq's- I personally don't think anything with a port should really be called a "monitor"- but there are some good ported designs.

Also I consider a multichannel volume control a must too for diy active systems. This is to be placed between the XO and the amps. FWIW I believe that if you are going active you should probably do it digital, I use cubase as my XO (on a 2nd machine) This gives you the advantage of A - freely choose your EQ algorythms B- high sample rates (and subsiquently lower latiencies) C- time alignment D- more optimal room tuning.

you should check out the forums at www.diy-audio.com for more speaker building stuff- A guy there just finished a great looking design with the ATC domes.

Anyway good luck-

RC

[knightfly]

Ryan, I got a 404 on that link several times; any fix?? Thanks... Steve

[serge instrumental]

I think tha this is http://www.diyaudio.com/ instead of http://www.diy-audio.com/