Mpl

[Joachim Gerhard]

I spend a fascinating evening on my system. the last days i had being working hard on my digital sound. I am using now an EUFL ESS9022 board an i have designed a filter-buffer to get rid of a small artifice i heard. The filter is now done but i could not find the right combination of harmonic extension and speed plus full tone and fleshed out images.
It dawned on my to the fist time that the resolution of my MPLs in the utmost treble was a tiny bit to gross. That never happened when i listened to vinyl but my setup is not shy in treble. In any MC cartridge a compromise has to be struck in the treble and the ones that are flat there ( over 10 kHz, that is ) have problems with tracking and dynamics because the moving system has to be damped more then is optimum for free movement of the cantilever-suspension system. Also there is more opportunity for tuning in a vinyl based system. A digital system is more rigid but also more accurate in terms of tonal balance. Do not misunderstand me, a CD player can sound thin and threadbare but this is not because of the mathematical incorrectness of digital per se. That has more to do with implementation like clocking, PSU and analog stage to name a few problem zones.
The sound of my CD system is spot on but there was this tiny bit of air missing or when i advanced the treble a small but audible tendency to sound artificial. I solved that problem now with integrating a super tweeter into the MPL. I will tell you more soon.
It is exiting to listen too BECAUSE it sounds so natural.

[Joachim Gerhard]

Here is a picture of the MPL with Mundorf super tweeter. I blend it in softly over 10kHz.
The minus 3dB point is even higher when i trust the simulation. Level is correct so i did not have to pad the Mundorf down. Crossover is very critical though and in the beginning i crossed too low. Resolution was spectacular but i lost a bit of a "one cloth" sound. Some treble energy came from too close from the baffles. I got i working though. Now the sound has much better resolution and air but the sound picture and not broken into separate pieces. What is really interesting is that musical instruments are now more easy to differentiate. That may be because of the overtones are better resolved. I checked the tonal balance with vinyl too and it is just fine. I am very satisfied and exited that i can still improve the MPL.

[Rudolf]

Originally Posted by Joachim Gerhard

I have now set up the MPL slim in my room. It sounds even more spacious then the 1.2m wide version. It is also arranged as a G-Pole with a back firing tweeter.

Originally Posted by Joachim Gerhard

Here is a picture of the MPL with Mundorf super tweeter. I blend it in softly over 10kHz. ... I am very satisfied and exited that i can still improve the MPL.

What I can't see from the picture: Is the Mundorf added to the G-Pole or does it supersede the G-Pole version?

Rudolf

[Joachim Gerhard]

I t is added. the G-Pole tweeter is still on the back. I know, it is complex but it works only in the upper most overtones. It is more a kind of "hush" that comes out of it.
Still is has a lot of consequences how the speakers image and resolve.

[Joachim Gerhard]

After around two years of continuos work i have decided on the final circuit for the crossover. This is a bit unusual because i normally do not need more then one day to design a crossover for a world class speaker. This may surprise you but when you have an
exact target modern computing does the job real fast. The MPL needed more time out of several reasons. One is that i changed the concept from 1,2 meter wide baffle to 0,6m wide baffle. The other is that i first worked with a wideband driver without wizzer plus horn ribbon tweeter, that was the famous Allen Wright Memorial Edition. It sounded very good too but ultimately i found it too ugly to look at. I have them still in stock so whenever Johanna wants to listen to them i can set them up. Third i added the G.Pole tweeters and forth i added the Mundorf Super Tweeters. Also the Enviee drivers went through a fine tuning phase and i had to check if the crossover constructed for one generation fits into the next. The work on the Enviee is done and surprisingly the crossover has not changed much. What took also some time is to adjust the G.Pole tweeter in level, response and phase. This and adjusting the super tweeter i did mostly by ear using simulation only as inspiration. Yes, i forgot : i listened a lot and did not measure much. That is an exercise for a mature speaker maker and reminds me of the good old times where we listened to music and not test signals. Mind you, the speakers measure great but the drive units are pretty decent to begin with. I had build the various crossovers mainly with parts from my junk yard so it was time to make something more professional. I did that the last days and have now mounted the very compact build into the MPLs. See a photo. The sound changed for the better but in a very supple way. Somehow it sounds more tidy and clean. Treble is more extended, midrange better resolved and bass is tighter and faster. Also the right channel balances better with the left. I always have to advance the right channel in volume a bit because my room acoustics are not totally symmetric by design to improve the bass and make the room more useful. I need less push on the right channel now and that makes the sound picture more symmetric. The higher resolution comes with a price. I heard more flaws in the recordings. I have my Titan i now run in well and i wanted to fine tune the cartridge setup anyway. To get more body into the sound i raised the down pressure somewhat and compensated the VTA accordingly. First i overdid it a bit but i found a good middle ground that sounds richer without loosing the resolution. I think i got the tonal balance back to neutral but the sound is better fleshed out like before but with a higher information content. I am satisfied and i await even better sound ones the xover boards have run in.

[Joachim Gerhard]

I got a major boost i sound quality in my system today by just placing my MPL Slim Panels more optimally in my listening room. I am working at the same time on a second set of speakers with field coil drivers, the Sommerwind.
I had placed the Sommerwind behind the MPL Slims, so i can take away the panels and listen to the Sommerwind. That placed the MPL Slims very close to my listening seat and blocks part of the back radiation. I had already found that listening as far away from the panels as i can improved the soundstage but then i sit smack at the back wall.
Taking away the Sommerwind allowed me to place the MPL Slim some 15cm further away and i am sitting now maybe 10cm from the back wall. They radiate to the back now without blocking. The resulting sound is extraordinary. Much smoother and spacious without loss of focus. Wider, higher, deeper and more sweet without loss of detail or dynamics. Not so well recorded material sounds less hard and better resolved. Classical
sounds awesome. I can play now also old material from the 50th and 60th on Decca, EMI, DG, RCA, Mercury without listening fatigue where before was a slight and penetrating hardness. Violins, horns and percussion sound wonderful, so do voices and choirs. The sound is more balanced and better separated the same time. Tonal color of instruments are much more easy to differentiate, for example open against stuffed trumpet. The bass got better too because i sit somewhat less close to the back wall. I could advance the volume of my subs by some 1 - 2dB without any boomy-ness. So i have more bass in total, that is faster and cleaner. This is so far the best sound i got in this room. I am planing now to layout a floor plan that i will publish on my MPL thread for later reference. I really unlooked the magic of my room and that after living ten years in this building.