It’s been a long time since I haven’t tweaked my speakers. After more than 9 years I decided to change the drivers after falling in love with the Alpair 10M from Mark Audio. I listened to my friend Andy’s system (4P1L PSE driving the Alpairs) and decided to get hold of them.
A simple upgrade
As I don’t have much time left for DIY audio these days, I needed a simple solution. I couldn’t build a new set of speakers despite the love I have for some horn-type designs. Bringing new speakers was out of the question, so I had to modify my existing boxes to replace the FE167E. Sadly they didn’t fit straight on, so my friend Tony made me a pair of adapter boards to fit these. Made of MDF I painted them in grey:
The build process took less than I expected. When I tested I noticed the treble to be higher than normal. I knew that some tweaking of the crossover was needed, in particular the level of the FT96H horn tweeter:
Indeed there was a need to attenuate the horn tweeter. I added an 8Ω wirewound L-PAD attenuator as shown below:
Calibration was very easy to do using REWL. A few sweeps were required to get the level about right. The remaining tweaking will be done through listening:
The results are good. Very flat response between 50 Hz up to 20kHz and above. The Alpair has a higher Fo=38Hz than my previous FE167E. I have a subwoofer so need to adjust the LF crossover to provide a better response below 50Hz:
Now, need to listen to these drivers. Allow them to settle in properly and provide some listening impressions. So far so good, the detail is impressive.
Nice look with that gold version. Howewer I’m not a big fan of L-Pad…Hope you’ll be satisfied with the results overall.
Why not? The HP filter I have includes resistor divider which is mandatory to set the tweeter level. The L-PAD when implemented properly will reflect same 8R impedance and reduce further tweeter level. I could rework the crossover and update the resistor divider. Not being lazy, just don’t have the time. The L-PAD were available. The entire upgrade was completed in 3 hours.
So far, it sounds really nice!
as a full range what do that all xover ?
Not sure what your question was. I don’t like the treble in the full range drivers. I didn’t like the treble in the FE167E and when I heard the Alpair 10M, I wasn’t very happy either with the top end response. I love the horn tweeter I have and has a great response even beyond 20kHz. My XO is 8kHz so quite hight.
Hi Ale,
Nice to see that you also get along with your speakers and making measurements 🙂
Great adapter board ! The speaker looks better with it and it gives additional diffraction.
Regards,
Danny
Hi Danny, thank you. So far so good, I’m very happy with the result and the sound is improving now that the drivers are breaking in more.
Thank you for all the tips re measurement. Next step is to equalise the LPF of the subwoofer to improve the response.
How are you getting with the preamp?
Cheers, Ale
Hi Ale, the preamp is in the startblocks, ltpsice sim is done 🙂 I’m waiting for my order of the transformers from AE Europe.
Watch out with measurements below 200Hz: change room, speaker/mic position and you get a different result. Not easy to hunt for the dragons in that area 🙂
Regards,
Danny
Good let me know how you’re getting on.
Yes, LF below 200Hz should be tricky. I just want to tweak slightly my LPF filter to ensure I remove a slight bump I have due to the Q of the filter. Too many knobs to play with!