Crossover options

I'm expecting delivery of a pair of Tannoy DC drivers (from their 90's CPA range) shortly, but they'll come without crossovers. I'm currently trying to obtain details of the original crossovers for the CPA-12 so that I can re-create them if necessary. Can't find the info on the web yet though, hoping Tannoy themselves might help me out as they've been very helpful in the past.

However, I was wondering if I could consider digital crossovers? Do they completely replace passive components and if so can I use a digital crossover in a system that comprises normal domestic equipment and an integrated amp, and an analogue source?

 

Electronic crossovers will take you to a different level.
Start with a simple one and get planning on a second set of amps.

http://www.meta-gizmo.net/Tri/bi-ampling.html

Love this...THE OLD HIGH SCHOOL GIRLFRIEND SHOCK...so true.
There is no going back.

 

youll need an amp per driver, the crossover goes between the pre amp and the power amps,and the power amps feed the drivers

 

Hi La Toilette

I reccomend Ashly analogue crossovers, and use one myself. xr1001, 2001 etc

http://www.ashly.com/product/xr-series.htm

It is the view of many experts on the JBL/Lansing Heritage forum that to get the equivalent 'sonically' from a digital crossover, you need to spend a multiple of 3 or 4 times as much on it. This would put you at about £1500-£2k.

I have a spare early Ashly crossover you can have for beer money (sounds ok but a bit crackly) or for a free lend if this would be of assistance. I live in Milton Keynes.

 

That's all really interesting, thanks guys. This might turn out slightly more extravagant an exercise than I first thought, but I'm not put off completely (unless my other 'arf finds out ).

Bottleneck, your spare Ashly; is it a stereo crossover and if so is the crackly-ness constant? (please forgive if stoopid questions)

 

Hi La Toilette

Yes, it's a 3 way stereo crossover, with of course variable crossover points. You can use different types of crossover slopes with it too - e.g. Linkwitz etc.

The crackling is just dusty pots, and only when you move them.

Its slope is 18, which is a small pace of the XR series. This manifests itself as a very slight (and it is very) veiling.

I used it as a stop gap whilst determining if 'active' was really the way for me.

I didn't want to invest £300 + on a new Ashley or similar ... so bought this, borrowed a spare amp and wahey.

I've been meaning to EbaY it for a while, but it will only fetch about forty quid, so can't be bothered with the advert.

cheers
chris

 

Right OK, thanks Chris.

I might mull it over for a day or two if that's OK, don't want to rush into acquiring kit until I'm sure that I'll follow the whole thing through, but it's a tempting proposition.

 

hiya

feel free to just borrow it if you like.. up to u mate.

cheers

 

What integrated amp are you using?The missus might notice extra boxes arriving if you get another amp if you go the active route.I would reccomend the Ashlys I use a XR2001 then you can stick something like a Crown K2 on the bottom end and use the integrated at the top.

 

My current amp is an integrated with no pre or power ins/outs (UR Unico), so probably no use for this experiment. At the mo' I use this with a pair of Tannoy monitor golds.

I do have a freshly serviced Leak ST20 that I don't currently use that I was already thinking of moving on, which would free up some cash for some other kit. I vaguely remember reading that Tannoy recommend the use of identical amps for bass and treble, so I'm assuming I couldn't easily use the Leak for this 'project' - or am I remembering that incorrectly?

The speakers I'll be using can handle quite a bit of power - they're basically a more robust version of the driver in the system 12 DMT's. Actually I might be able to use studio amps as they'd be hidden in my hifi cupboard so shouldn't offend the sensitivities of my beloved, as long as she can still work out how to turn everything on!

BTW it's probably quite obvious but I'm really groping around in the dark with all this stuff as my setups have previously been fairly normal domestic integrateds or pre/power + passive speakers, so bear with me .

 

I am temporarily using an integrated amp on the treble unit,obviously gains are different with all three amps but the two pro amps have gain controls (MC2 650 and Crown K2).Then you can change the system volume with the gain control on the crossover eg no preamp.

 

What Smithy said.


The volume control on the integrated is immaterial, as you can control volume on the crossover. You would just whack the integrated on full.

I wouldn't worry about 'sonic perfection of amplifiers' for now.... you will spend not inconsiderable time in the future trying different permutations of amplifiers on bass/treble or mids too with a 3 way.

 

Good to know that I could experiment with a single extra amp and the crossover, that makes things less expensive, well initially at least.

The drivers are dual concentrics and therefore 2 way, I guess you can just use the crossover for the two drivers each side rather than 3? Can I add a sub as a 3rd driver at some point?

Anyway, the drivers have now arrived and despite being sold as the same model, they are quite obviously different - one having a pleated/corrugated surround and one having a rubber surround. I have a feeling that this might make a noticeable difference to how they sound, so my first job now is to try and work out what model of drivers I actually have, and if they're not close enough to each other in performance I won't be doing anything soon!

Grrrr

 

Yes you can use it 2 way to start with you could also if it were deemed neccessary put a supertweeter on the top end.The Ashlys have balanced outputs so you will need a handfull of XLR connecting cables.

 

You could start here; http://tech.groups.yahoo.com/group/tannoy/files/Tannoy DMT215 speakers/

The DMT 15 xovers are simple affairs, the only difference for you would be dropping the tweeter level to match the lower sensitivity of the 12" compared to the 15" bass driver. I'd make the series resistor on the treble section 10 ohms and see how that goes.
Cooky

 

Thanks for the link Cooky, the DMT crossovers might well be another way to go as the drivers are so similar. Simple for you maybe, but not simple for me, but probably just about manageable .

I got a reply from Tannoy about the drivers and apparently I have one from a CPA12 and one from an i12, but they use the same chassis, hf and magnet assembly so I can get one reconed to make them a pair. The seller has kindly reimbursed the price of the mis-identified one but still let me keep it, which means that he's covered about 1/2 the cost of having it reconed by Tannoy, or 3/4 of the cost of a recone kit if I do it myself.

Still interested in the Ashly as it would be a comppetely new direction for me, but just a little concerned that all those extra boxes could still bother the missus .

 

forgot to mention - would have to look at the crossover points you want to use, to make sure the ashly I have allows you to crossover at those points.

If you find the crossover points, I can let you know.

If you can borrow a 2nd amp, it would allow you to experiment with active and passive on the crossover.

 

This is from the i12 brochure:

Passive 1.5kHz
2nd order high pass, 2nd order low pass

DMT 12's crossover point is 1.4KHz.

 

You know, given that it is a simple two way... my estimation is that you may be better with a passive crossover.

Active's seem to provide special benefit between bass and mid-bass.. and really a dual concentric is a woofer with a horn tweeter..

 

You know what Chris, I think I might scrap the whole project.

I picked up the drivers cheaply enough but as mentioned before would need to get one reconed to make a pair, and they're really PA drivers. I have read of people successfully using them domestically but maybe I'd be better off sticking to gear that's designed for what I'll use it for - be a bit of a waste of time pfaffing around if I'm always fighting their true character.

Incidentally I mailed Roger at Lockwood audio, who said:

"Agreed, these are PA designs which may not give the refinement normally required for domestic monitors. Electronic crossovers (not obtainable from us) would allow for bi-amping and a higher level of control."

So electronic xover could probably be the preferred option, but even so....

He did also say that I could get these reconed as System 12 drivers, which would be nice, but by the time I've spent £250 on having that done, plus whatever crossovers and cabs, I may as well just buy a pair of the complete speakers!

Yup, I think I'll drop this one before it starts costing too much to stop !

Dave