Crossover simulation

[Vivek]

Hi all,
I have built three pairs of speakers till now. The latest one is an MTM using Vifa TC18 and D27 drivers. The MTM was made with help from a friend.
I was wondering if it is really necessary to design and simulate the crossover with Speaker Workshop or such other software. Will a rough design and then tuning by listening not do? I understand that one can try and smoothen out rough peaks if simulation is done but is it very necessary. Of course, I will measure the impedance for accurate TS parameters.

Thanks and regards,
Vivek

[HK26147]

I would measure T/S & impedance 1st of course, as drivers are notoriously off T/S spec. An impedance sweep will find also find leaks and resonances.
Before I had the capability to measure T/S & impedance, I built many crossovers ( using design guidelines, articles and advice ), and using listening as the final judge.
It is easier to make the crossover external from the cabinet and "breadboard" it. This allows for quick changes and listening evaluation.
For MTM's I start with 3rd order L/R ( as per the original design of Joe D' Appolito ).
Probably 2500Hz for the D27.

[sreten]

Originally posted by HK26147
.
For MTM's I start with 3rd order L/R ( as per the original design of Joe D' Appolito ).

Hi,

There no such thing as 3rd order L/R.
J.D'A's original work used 3rd order Butterworth.

/sreten.

It is "necessary" :

http://www.rjbaudio.com/Audiofiles/FRDtools.html
http://www.geocities.com/woove99/Spk...esigningXO.htm

[Dr. Ram]

Originally posted by Vivek
I was wondering if it is really necessary to design and simulate the crossover with Speaker Workshop or such other software. Will a rough design and then tuning by listening not do? I understand that one can try and smoothen out rough peaks...

Ask yourself this: "What do I lose if I do simulate the crossover?" With freeware like Speaker Workshop (which I have used), you get very good results with a very small learning curve. Then again it depends on how sensitive you think your ears are, and different people have vastly different sensitivities. If your ears can detect +/- 2 dB easily, you should certanly use simulation.

HTH

-Ram

[Vivek]

So it looks like the opinion is more or less unanimous: that I do it the modern software way.

[HK26147]

Opps...
sreten is correct
I mistyped too soon.
I did use the copious material Joe D' Appolito and other crossover designer detailed in Speaker Builder ( prior to PC sim software ).
Ultimately my ears are the final judge.

[PeteMcK]

were you happy with the results of your first 3 speakers, without simulation? Sims might get you there faster, but I don't think they are absolutely necessary if you understand crossovers. More important are ACTUAL measurements, before and after...

[Dr. Ram]

Originally posted by PeteMcK
More important are ACTUAL measurements, before and after...

In any engineering discipline, design/simulation and measurement are complementary. You first design and simulate, say, the engine of a car, then build, measure and refine. You don't "just build" and then tweak. You could, but you would waste lots more time, energy and money getting to the end result.

[Vivek]

Pete, the first two were built without any simulation. The third one was all done with software but like I said, I did not do much. My friend did most of the work and I just wound the coils, assembled the XO and the speakers. They sound nice. But I though I would learn to do this too.

I have a half-built Wallin Jig for measurement with Speaker Workshop. I think I will complete it and see what I come up with.

Ramkumar, I think you and I used to talk on the phone some years ago. You bought Peerless India drivers and had built an active 3-way system if I am not mistaken.

Sreten, thanks for the links. I will go through the pages.

The midbasses I am getting are Peerless India SKO165 polymer coated paper (6.5 inch, 4 ohm). I plan to mate them with the Vifa D27.

Vivek

[sreten]

Originally posted by PeteMcK
More important are ACTUAL measurements, before and after...

Hi, True if you can do measurements. Simulations help tuning by ear, /sreten.