Kestrel 2 crossover question

Pat, uses first order simple crossovers, no l-pad or zobel networks. In this speaker, as well as other current models, he uses a minimum of components. I've heard this speaker and it is pretty good in some areas.
Nate

AllCaster said:

Looking to make a Kestrel 2 copy. The drivers are the Peerless HDS 182 6-1/2" and Vifa XT25TG30 1" dual concentric dome tweeter. I think the XO point is between 3,000 to 5,000Hz. Does anyone have an idea on the values for the XO, for a first order design? It may (or may not) need a Zobel for the woofer or an L-pad on the tweeter. This is my first DIY for speakers. The cabinet should be far more complicated than the XO. Thanks.

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At sucha high XO (well over 3k) the Peerless unit has turned into a beaming soundsource. You will most likley have a shift in sound caracteristic in the cross over area (from non beaming to beaming to non beaming tweeter).

I'd try a bit lower XO freq.

The tweeter is a real PITA to make a 1st order XO, I've made some simulations with my measurements of it, and if you want 1st order slopes 6.8 uF will suffice (starts rolling of at ~5 kHz, 3 dB down at ~3 kHz). In combination with a series resistor of 3.3-4.7 ohm you can attenuate the tweet a bit, although I recommend to use a shunt resistor aswell. Then I can shape the response a bit more.

Thus: 1cap 1R gives on tweet: 6.8uF and series R of 3.3-4.7 ohm


Or:
1cap 2R (a proper Lpad): gives 5.6uF and series R of 6.8 ohm and a shunt R of about 15 ohm.

Because I'm using measurements of the tweeter on another baffle YMMV and I can't gurantee optimum performance.

The woofer you mentioned I've never used, but because it's a polyprop which behaves well I would experiment with 1.5 mH - 2.2 mH series coil.

Good luck and don't forget that distance advice is very difficult for this kind of questions.

Re: Re: Kestrel 2 crossover question

EngelholmAudio said:

At sucha high XO (well over 3k) the Peerless unit has turned into a beaming soundsource. You will most likley have a shift in sound caracteristic in the cross over area (from non beaming to beaming to non beaming tweeter).

I'd try a bit lower XO freq.

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You are right about that, but then the tweeter isn't cooperating anymore. I would suggest atleast a 2nd order electrical XO at 2-2.5 kHz in that case the midbass isn't beaming that much and the tweeter can handle it easily, but then again it wouldn't be a "Kestrel" (by the way what is a Kestrel speaker???)

In general, that Vifa tweeter does not really like low order crossovers.

See sheldon stokes website and his making of a vifa P13 and Vifa Radiator mini monitor.

Note his comments on the tweeter.

Also, the Kestrek 2 may not be using off the shelf Vifas.

IMHO, 1st order crossovers are highly overrated.

Okedoke heres what I know about this speaker from my hifinews review. There is a measured response of the tweeter, woofer and combined.

There is a large area of overlap from about 1500 to 5000hz between these two drivers.

The f3 on the tweeter looks to be about 3.5khz and the woofers is about 2.5khz.

To be honest with you the review they got was a mixed bad, certain things were like and certain things we not. The good bits were basically what the woofers good at and thats bass and rhythm, I can tell you the HDS series are good at this, infact they are excellent for the size of the cone.

They also say that they image well, but they have a slightly recessed sound which mutes detail and the trebble is rolled off in the top octave which gives a slightly dull sound.

Id personally use steeper slopes with these drivers, especially with that tweeter.

They also say in the review that since they had started using this tweeter with 1st order they have not had a single device die. However the XT can handle lots of power and has a low fs, which would indicate that it can handle power, and it can, what it cant do is sound good with a low XO and high SPL.

If you want ease of use then go for the scan93. It can be used really low which should work well with the woofer. Cross between 2k and 3k, where ever suits good integration and you will be cooking.

I have a design with the 6.5" HDS with phase plug and scan d2905 95 in the pipeline, im waiting on some wire to arrive so I can make the inductors. But early results are really promising.

This is slightly off topic but does anyone know which woofer is used in the original Kestrel??

The LDSG says it's the vifa M18 but this is clearly not the case! (isn't the LDSG supposed to be reliable??)

I would say it's one of the P17's, I just ca'nt tell which since i don't have a detailed enough picture of the speakers. Maybe someone can tell me.

thanks, sardonx