What would you do with a load of revelator drivers???

nannoo

Member
2013-01-15 4:32 pm
Hi guys,

Recently I picked up 4 scan speak 15w/8531K00 mid woofers and a pair of D63004/660000 tweeters. Grabbed them as they were cheap and I'd always planned on buying them one day.

when I have time and money I'll build them into a propper 3-way set up, but in the mean time it seemed a waste to have them 'laying around'.

So what would you do with them?
What would be a fast and 'safe' build?
I was thinking ported MTM, buit this is my first time with a build like this.

At the moment it would seem a 32L ported enclosure would give me reasonably flay response down to about 50hz, and 'useable' response to 30.

Also, from the fr data alone i was planning on xo at 1khz, but almost all the revelator designs seem to xo at about 1750.

I'm pretty concerned about the high efficiency of the tweeter vs the woofers, and have read online that a LCR pad is almost always needed with a 660000 rather than a standard L-pad, but I only have experience with the later?

Any ideas and suggestions are welcomed, be it open baffle, sealed enclosure, ported, even TL! basically what would you do as a cheap, safe build?
(by safe I mean 'predicatable or adjustable performance' prior to building!
 
Hi, troels gives some directions using the midwoofer but with other ss tw. IMHO I would go for an active crossover, the dsp is so cheap and with two dedicated amps and a flexible crossover to change "on the fly" the frequency, delay, phase, it is just so easy to have an very good sounding speaker...
But if you still wanna a passive solution I ould go for the zaph audio one
Zaph|Audio - ZRT - Revelator Tower the driver is bigger so adjust for your parameters and you will be very satisfied.
Good luck
Murillo
 

nannoo

Member
2013-01-15 4:32 pm
Where should I start with adjusting parameters of this design?
I'm a noob to cabinet design and calculations, only just gotten my head around loudspeaker theory and crossovers, i'm starting to think that ignoring cabinet design all these years has been a grave error!

I always intended on starting with building PSU's and amplifiers, but these drivers have changed things.

Also, active XO's make a lot of sense, I have a 5-channel power amplifier in the bedroom where I'd want to use these speakers, so relatively easy to implement... except, I don't know anything about active XOs and the whole point of this project is to be quick and easy... so unless there's a cheap introductory (and high quality?) active xo kit I'm a little stuck.

Also, as there's also revelator subs available, would an active xo allow me to implement a 2.1 signal from a digital/line level stereo input?

thanks all
 
1kHz crossover? I don't think so...

The interesting question is what are these drivers like? The bass is almost identical to the coated W15/8530K00. Actually yours is a couple of dB louder, but that's about it.

So Troels' Ellam-98 is not a million miles away with a 2.3kHz crossover:
Ellam-98

Your tweeter is about 4dB more efficient than his metal D2904/9800, so a bit of fiddling with the 5.6R input resistor might get you the 2dB you need. Say 8.2R wouldn't be unreasonable to get 2dB attenuation.

Bit rough and ready, but worth a go, I'd think. :)
 

Jay

Banned
2003-02-11 9:02 am
Jakarta
Recently I picked up 4 scan speak 15w/8531K00 mid woofers and a pair of D63004/660000 tweeters.
I think I understand why they are sold. Good speaker design always start with the right choice of driver combo. You may need extra money to build the crossover for the tweeter, and it is not my cup of tea either.

when I have time and money I'll build them into a propper 3-way set up
They are not suitable for 3-way.

Also, from the fr data alone i was planning on xo at 1khz, but almost all the revelator designs seem to xo at about 1750.
Tweeters with this kind of voice coils have performance that gets exponentially worse with lower frequency. You don't want to cross it too low unless you match the tweeter with bigger woofer incapable of being crossed too high.

I'm pretty concerned about the high efficiency of the tweeter vs the woofers, and have read online that a LCR pad is almost always needed with a 660000 rather than a standard L-pad, but I only have experience with the later?

There's really no issue with high efficiency. It's 4 ohm. And paralleled woofers will increase efficiency.

The LCR is only a consequence of crossing lower than "normal" tweeters.

Any ideas and suggestions are welcomed, be it open baffle, sealed enclosure, ported, even TL! basically what would you do as a cheap, safe build?
(by safe I mean 'predicatable or adjustable performance' prior to building!

It's a difficult design and you seem don't have the skill to design your own so stick with a proven design suggested by others.

In your position I will build 2-way design (if proven design is available) and sell the speaker. The other woofer pairs will go with a better tweeter, and sell them also. The money will be used for a better drivers :D
 

nannoo

Member
2013-01-15 4:32 pm
They are not suitable for 3-way.

I should have been clearer, I will add either another revelator bass driver or an alternative if something more suitable presents itself, at this stage it very much looks like I'll be sticking with the revelator series (though some tang bands have really caught my eye)

Better drivers? from what I'd read online revelators were near the top of the crop, what else would you be looking at and why?

thanks to all for the responses, it's greatly appreciated!
 
I don't know about adding a bigger woofer. It could be done, but would be a considerable homework problem. Troels has a design that might be adaptable:
JAZZMAN

But more to be found in his Ellam designs for your purposes:
DIY Loudspeakers

Not many people know this...but it is very easy to convert a two way design to a series wired D'Appolito:

...snip...The series wired D'Appolito has a very simple connection. You wire the two basses and two bass filters in series, along with a single tweeter and filter. The levels work out, leaving the elegant conclusion that converting a standard two-way to a series wired D'Appolito is almost trivial. Bass impedance doubles, of course. :D

Simplifying the resulting bass filter is then a simple exercise of halving and doubling the component values. IIRC, you halve capacitance and double inductance and resistance.

The parallel wired 4 ohm D'Appolito is altogether more complex to design. :scratch1:

Couple of cabinets for wherever you reside:

US 20 Litres: The Madisound Speaker Store
UK 11 Litres: Mercury cabinets
 

Jay

Banned
2003-02-11 9:02 am
Jakarta
I should have been clearer, I will add either another revelator bass driver or an alternative if something more suitable presents itself, at this stage it very much looks like I'll be sticking with the revelator series (though some tang bands have really caught my eye)

Better drivers? from what I'd read online revelators were near the top of the crop, what else would you be looking at and why?

These are the worst of the Revelators. I guess the promise was that the tweeter can be crossed low to meet with 8531 peaky response at the mid frequency. Yes you can do it with expensive crossover but I doubt the result (I think it was a failed promise). The tweeter has high IMD distortion if I'm not mistaken.

Multi way (3-way) is about putting drivers at limited bandwidth at which they can work comfortably. 8531K and the tweeter is a combo where each driver must be stretched. To make it 3-way, a midrange is required, but very difficult to find a driver suitable for that too, and the woofer is too small (cannot go low enough) for a 3-way.

The reason to build 2 speakers from the drivers was that because imo it will generate more money that way (to fund a better project). There are always people who think that it is a Revelator so it must be good and worth the price. You may disagree tho.
 
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nannoo

Member
2013-01-15 4:32 pm
The tweeter has high IMD distortion if I'm not mistaken.

I think you are, but if you have a source please let me know, all the measurement data on the 660000 I've seen (independant, not scan-speak) has shown superbly low distortion figures.

Multi way (3-way) is about putting drivers at limited bandwidth at which they can work comfortably. 8531K and the tweeter is a combo where each driver must be stretched. To make it 3-way, a midrange is required, but very difficult to find a driver suitable for that too, and the woofer is too small (cannot go low enough) for a 3-way

As stated, the 15w would be the mid-range. I would be adding a bass to the set up, the 15w's would most likely be in seales enclosures.

Do you mind if I ask where your your opinions are from? you seem to dis-like them...
 
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Jay

Banned
2003-02-11 9:02 am
Jakarta
As stated, the 15w would be the mid-range. I would be adding a bass to the set up.

Then you have to stretch the 15W and/or the tweeter. Just ask yourself, what will be the crossover frequency for this 2 drivers?

So you will add a bass driver to this combo. Then you have to think about: (1) Should Scan-Speak bass driver be used? It will be very expensive, and the speaker must live up it's price! (2) What will be the tuning frequency? You should start with measuring your listening room to find out if you need to go to 20Hz or so.

Do you mind if I ask where your your opinions are from? you seem to dis-like them...

Okay, may be it is just me. I always try to get the best. And for me good speaker design must start with good driver choice (the drivers and the driver combo) and a thorough plan of course.

Not about like or dislike, but Scan-Speaks are very expensive for the price. They were the best at their price in the past. Nowadays, only certain models worth the price imo.
 

nannoo

Member
2013-01-15 4:32 pm
good to know, these drivers are from a pair of YG acoustics anat II's, so there is the option of securing the bass drivers at a reasonable (still HIGH) cost.

If I could achieve the same performance for a similar price I'd defineately like to hear about it (if you want to recommend any drivers that is) for me, the tang band woofers are the one's that have really caught my 'value for money' eye.

Can't say that any of yg.a.'s engineering has impressed me at this stage, they seem to have an agenda to rip off as many as possible...
 
I have the Zaph ZRT 2.5 way. They sound great sealed. The crossover transfer functions for that speaker could likely be reapplied if you keep the same front baffle width but you would have to customize the actual components.

I have heard this combo in a transmission line and they sounded fantastic. I would highly recommend this option. I am considering rebuilding my sealed enclosures they were so good.
 

Jay

Banned
2003-02-11 9:02 am
Jakarta
these drivers are from a pair of YG acoustics anat II's

This must be a joke. There is no reason for such an expensive speaker to use 8531. Even 8530 is a much better option. How do you know that YGA doesn't use custom order drivers? Do they stick a sticker behind the woofer saying Scan-Speak 15W/8531K? This audio world must be full of fools :dunno:

If I could achieve the same performance for a similar price I'd defineately like to hear about it (if you want to recommend any drivers that is) for me, the tang band woofers are the one's that have really caught my 'value for money' eye.

I think it is not difficult to reconstruct the MTM with 16dB/octave at 1k75Hz. The big woofers are just acting like subwoofer.

I have never found any subwoofer that "work". It is difficult to find a matching subwoofer at 75Hz. That's a crazy engineering. And you got to have big listening room.
 
These are the worst of the Revelators. I guess the promise was that the tweeter can be crossed low to meet with 8531 peaky response at the mid frequency. Yes you can do it with expensive crossover but I doubt the result (I think it was a failed promise). The tweeter has high IMD distortion if I'm not mistaken.

What peaky response do you mean?

The 15W Revelator is one of the smoothest mid-woofer I've ever measured!

Here are measurements for the 4 Ohm version of the un-coated 15W Revelator. ScanSpeak 15W/4531G00 Measurements!

Multi way (3-way) is about putting drivers at limited bandwidth at which they can work comfortably. 8531K and the tweeter is a combo where each driver must be stretched.

Sorry, I have to disagree. ;)

Cross them over between 2-3kHz and neither of them will be stretched at all.

These are excellent drivers to build a 2.5way or perhaps a D'appolito 2-way. If you don't think they can produce enough bass (which they can in a normal sized room), add an active sub.

Here you also have measurements for the ScanSpeak D3004/660000

Regards

/Göran
 

Jay

Banned
2003-02-11 9:02 am
Jakarta
What peaky response do you mean?

Your measurement of the 8531G indeed looks very good. Here's different FR based on datasheet between 8531G and 8531K
 

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nannoo

Member
2013-01-15 4:32 pm
I have the Zaph ZRT 2.5 way. They sound great sealed. The crossover transfer functions for that speaker could likely be reapplied if you keep the same front baffle width but you would have to customize the actual components.

I have heard this combo in a transmission line and they sounded fantastic. I would highly recommend this option. I am considering rebuilding my sealed enclosures they were so good.

Could you tell me more about the transmission line design? was it a single woofer into a transmission line or two?

Transmission line would make me nervous because of the 'getting it right' factor, but the reality is it would be very easy to build an enclosure with an adjustable TL length, and that is rapidly looking like the way to go. With the ZRT being so well recieved, it's very tempting to jump on that - not least because the crossovers give me a great start, the rest would be tweeking as I'd have the 15w's wired in parallel.

How does a 2.5 way system effect overall performance? (output level, distortion mechanisms, frequency response)

whilst looking around for a 2-way MTM design i came across previously i stumbled upon this, site, anybody seen these things before? they're making some pretty bold claims...

https://www.hypexshop.com/