Some people have provided me feedback and even measurements of what they have done with this active crossover kit.  Here's some stuff in no particular order (page under construction).  If you want to send me anything RE what you've done with the kit, I'll try to get it posted.  If you already sent me stuff, and its not here, please remind me.

Attached is a .gif file of the xo response measured by my CLIO system. I
measured both amplitude and phase, and the plotted total response is the
true coherent response of the complex sum. The left channel is flat to
within +.089/-.063 dB, and the right +.064/-.091 dB. The 2nd and 3rd
harmonic distortion was measured around -80 dB, but that is pretty much the
CLIO measurement floor. Looks good to me.

Regards, Art Ludwig
http://www.silcom.com/~aludwig/contents.htm

Hi !

First I want to thank you for your very informative page about the Active Crossover DIY kit. It truly inspired me to start the project I've just finished. I have been experimenting with speakers in many years, and thanks to you I now have a fabolus 4th order solution to the crossover problem and I can lower my -3db point significally with a bass eq.

Using your xls chart and the simulator Simetrix (what a powerfull program!) I choose a setup. I bought the breadboard and parts (only TL072 and normal caps) in the local store and I had a supply already. My speaker system is a budget and brilliant (I think) mixture of HiFi and SPL. Midtone and tweeter is the Infinity Reference 11i which is a cheaper bookshelf speaker with a surprisingly nice sound. I haven't touched its crossover since its in a fine quality and well designed.
The bass system is a little more brutal however. Two Cerwin Vega XL-15Ds in 135 vented liters each... They tears my room apart! and sounds nice and fast too. But before I made this genius crossover I couldn't cut them off properly and they wrecked my midrange with ringing resonances. Now this is history and my tiny midranges doesn't get in trouble with the bass anymore. Very nice! I have also made my own version of the Shiva bass eq that features a variable deepbass gain, so I can go flat when playing loud.

The reason why I'm writing is mainly to thank you for your site....

Well, I won't take more of your time. Keep up the good work!

Lars Pontoppidan Larsen

I wouldn't even have a chance @ making this thing work right if it weren't for active design. Your kit is the ticket.

Doug Pennington

Glorious news….

In a spare hour this afternoon, I decided to install the ‘volume
control’/attenuation module in my breadboard for my bass channel (I had
previously only done this for the tweeter and mids). As soon as I fired up
the system it sounded f**king marvelous!!! Something significant in this mod
has made a HUGE difference to the mix of the sound. It all sounds so much
more integrated and ‘warm’. My suspicions are that the phase of the subs is
now correctly the same as the mids (180 degree rotation presumably by virtue
of the fact that Im using one opamp ?). As you may have felt from my
previous corresponence, I was not completely sure about the system but now I
am! Before this change this afternoon, I was under the impression that
either the Peerless mids were not upto the job or that Id selected too low a
Qb for the mid chamber or that Id just messed up the whole design somehow.

Everything sounds so clear now – Ive just tired out about 4 of my CDs and
for every one of them I felt I just wanted to keep turning up the volume – a
sure sign that it sounds good for me. Alas, poor neighbours!

Off for more happy listening….

Neville.

The documentation looks nice and seems even
a beginner can understand.  I will be working
on the kit soon but will not be completing
the sub for a few weeks.  Your time and effort
on this project is very much appreciated.  My
limited funds make this a wonder....  I would
not have been able to experiment with active
xovers without your work....  The ability to
understand and modify this circut adds one more
plus +++++ to the project....

Thanks Again
ledger@netvi.com (Ryan Ledgerwood)

THE SUBFILTER IS UP AND RUNNING!!!!!!!
I have just tested it and it works just fine.No hum or anything else
that shouldent be there.
Real good step by step guiding,overall very good doc
Thanks from a happy Anders.

John,

I wrote to you some time ago about the active crossover I built and promised some pictures. There are a few attached here so you can see the final product. Let me know what you think, and thanks again for making such a great kit available at such a low price. The finished product looks and sounds great! All the pictures were taken with a Sony Digital Mavica camera, and I threw in a picture of a Dynaco ST-70.

Later,

Owen Columbus