Tweeter integration on TAD 2402 speakers

Right then...

I have TAD 2402's here...love them to bits. Recently i got thinking about integrating one or more tweeters so I bought some Pioneer PT-R9 ribbons with ALM-HP105 filters. The filters have attenuation built in and cross over at 10.5khz, perfect for the TAD's.

The TAD TD-4001 mid/tweeter starts to roll off towards the top. While i think its very easy to listen to as a speaker I do hanker for increased clarity.

These guys in JP use the same ribbon tweeters and filters with their TAD speakers. They also use a pleathora of tweeters!

http://www.tees.ne.jp/~denkiya/newpage4.htm



Wondering about a crossover for the mid/woofer section. Thinking about a vintage Sony TA-D88 or TA-D900. Anyone got experience with this?

I'm interested to either, run the Berning as a single amp to drive all stages...or...run a Leben RS-28CX pre with Yamamoto A-02 for the tweeter and the Berning for the mid/woofer.

Would it be possible to run a digital eq first to check the setup, correcting afterwards with analogue methods...step by step approach?

Cheers

R

 

Hi Rich,

Nice looking loudspeakers. I love the way the Japanese use the multiple ribbons - I can only assume for sensitivity purposes.

I don't have experience with the TD-4001 - only the 4003. They are however similar enough for certain facts to apply to both. The below graph is the response of an unaided TAD 4003 in a TH 4003 horn.



The important aspect is the notches that you see in the response in the uppermost octave, evident as the output tails off at around 6db per octave. These appear to be break up modes from the 4" beryllium diaphram and they are audible as a slight courseness in the response.

The standard trick with those monitors is to roll a supertweeter in 1st order at around 10-12khz in order to dovetail with the acoustic slope of the 4001. This has two issues for me. Firstly, the breakup modes' non linearities are audible, and secondly, using one electrical and one acoustic first order like that will lead to phase issues and comb filtering in most cases.

The solution I use with the TD-4003 is to insert a third order passive crossover between the mid and tweeter at 8.5khz. This is high enough to not affect the midrange, but low enough to attenuate the TD-4003 sufficiently to effectively remove the break up modes. This leads to slightly better extension, but far more importantly to me, a better quality of high treble, giving more delicacy and air to the proceedings.

The crossover design itself is pretty simple assuming you have the impedence curve for the 4001. Once assembled and wired in between the 4001 and tweeter, you can experiment with resistors to fine tune the attenuation of the tweeter. Parts costs depends on how far you want to go. I didn't need to spend much - six caps, six air cored inductors and a few resistors doesn't have to cost the earth.

I'm very happy with the results of mine and feel that applying a low pass to the TD-4003/4001 is more or less essential given their 4" diaphrams. Maybe the 2002/2001 are less of an issue. I'm still tweaking levels and time alignment but even with a rudimentary setup, I would say the addition of the ET-703 transformed the speaker. And of course you could continue to use the Berning for the full range. Let me know if you need any help.

 

Hi Mic

As always a good response.

The filters for the tweets have 3rd order slopes...so i guess the filter at 8.5Khz for the mid/woofer would be ok. I could use attenuation for the rest.

As a low pass crossover I reckon like you suggest, 8.5khz might be a god bet. I have my eyes fixed on a rare Sony TA-D88 crossover...talk about rolling back the years. It gives me a bit of flexibility to begin with.

I could use the Leben as preamp, feeding the yamamoto a-02 amp (with Kondo spz) for the highs and Berning for the mid/low. Or, just the Berning direct, which could bring more noise....although less cost and wiring.

What are your experiences with the DEQX? Could it be feasible to use one of these to begin with...just to evaluate timings and then adjust the analogue crossovers until things are correct?

I'm just interested to plonk them on and see what happens. Learning by doing always the best way.

 

My 8.5khz suggestion is only if you use the ET-703 Richard. The ribbons are designed to be used with the TD 4001 left wide open - something that I don't like to do based on experience with the 4003.

If you are going to go active, then you need to go active between the 1601 and 4001 and passive further up. Even then, you will need a hell of a good crossover to make it worthwhile. In my experience, the likes of the Bryston 10B and DEQX need not apply.

 

If you were to go active what crossover would you ideally go for? Something custom made maybe?

 

If I could get away with it I would go for a line level passive solution, but the slopes I use really preclude that. The Pass Labs XVR-1 is head and shoulders above the others that I have tried in both flexibility and it's ability to not force it's sonic footprint onto the music.

I have not tried the latest PC solutions, nor the FM Acoustics unit. But I don't feel inclined to do so. Every PCM solution I have tried has taken away far too much of what is important to me. I think the Marchand XM 126 might be interesting, but it lacks the Pass Labs flexibility. It might be an interesting option to try though. Another might be an old Accuphase - say a 25 from before the switch to digital filters. The digital units again seem to leave too much of an imprint for my liking.

 

I belive Jadis make a valve active crossover. I was looking at one to go with my SPJ laluce line array towers.

Mic, Tenson I may have to get you over to to help me out.

cheers

Paul

 

Apparently the Sony unit was rated above the Accuphase analogue units..and for a german mag to say that haha...that is something.

 

Personally I'd be wary of using a vintage active crossover Richard. If you think of all the components in the signal path that will probably be well past their sell by date. The crossover will make or break a loudspeaker, be it active or passive IME, and you really want to be sure the components are working to their best ability. My solution would definately be a passive 3rd order with the ET-703 using the ZH270 full range. Whilst a nice amp like the Yamamoto will give you a little more timbral sophistication, it will probably come at the expense of cohesion and at quite some cost to your wallet.

 

What have you bought Paul? You've not been talking to Richard again have you?

 

Valve powered, oh yeah. Bet that sounds sweet as a nut. My feet are tapping already.

 

Out of interest, do you think valves would colour the original recording any more than PCM based DSP? Do you not think they both leave their inprint on the perceived sound quality, and it is for the user to judge which they prefer?

 

Mike, you know where I stand and likewise.

In terms of objective performance, the results clearly swing in favour of the DSP. Subjectivity seems to be a machine to just convey world views without any real facts that are broadly applicable.

So whilst it would be interesting to dissect what your asking I feel it would have no real worthwhile outcome. No opinions would be changed, no revelations would out and the whole thing would be pure deja vu seen a thousand times the world over.

 

You are probably right. It would be highly interesting however to do some blind comparisons using the latest DSP based crossovers vs. say a Marchand XM126 and Manley Massive Passive.

 

Not done it blind but did some rather tiring(for me) comparisons of various methods both active and passive. I'm sure I've mentioned this before though.

Nothing in it really until you start to factor the driver and room correction. If your looking for just a crossover filter then any of the above is good choice.

Definite and clear improvements were only realised once the correction was introduced otherwise most differences noted were entirely down to my imagination and when asked for second opinion others would comment they were virtually identical if not identical.

What I did was by no means exhaustive but was more than enough for me to close that chapter of the book.

I agree it would be interesting revisit the comparison. Especially considering the advances in the SOTA.

 

Which DPS based units did you use?