F5....and Martin Logan Sequel Panels?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
All,

My F5 construction is progressing well--thanks to all the DIY'ers out there who have once again piqued my interest in audiophile things. (Thanks)

A question. I have a pair of pristine Martin Logal Sequel panels in storage, and have already built HV power supplies and ESL driver transformers for them. My intent was to use them with an Onyko Integra "Grand" amp I have. I'd use the Sequels for mids and highs, with a hefty Class D plate amp and 2 x 15" woofers in transmission line enclosures for bass. (Have a Driverack 260 that I'll use for crossover and equalization).

I'm pondering how well the F5 would match up with the Sequel panels. I suspect the efficiency of the panels would be problematic, when used with the F5. Anyone have any thoughts about this combination?

Thanks--if nothing else, when the amp is done and I have the TL subs built, I might have to settle in with a good bottle of Merlot and experiment.

Ken
 
Hello,

I tried the F5 with an Apogee Stages and a Quad ESL2805. Superb with both loudspeakers, the best sounding amplifier I tried with the Stages, but a bit short of power on both.

I believe will be a nice idea use two F5's, one per channel in bridge.

With the Apogees the amplifier runs cooler

Cheers....

wouldn't bridging be worst due to the impedance ...? cant imagine an F5 powering Apps..



It will play, but it's really not enough power - even bridged or "X" versions are a little low in power imo... you need voltage swing for ESLs...

_-_-bear

and Current for the Apps ...
 
Quote: "Having an pair of SL3's myself, you need to design in a skanspeak mid bass driver between your proposed 15" woofer and ML panel. The stock SL3 has a terrible mid bass to speak of already with its 10" woofer transition."

----Great minds, David, on your comment above. Actually I've bought a dozen 7" shielded woofers (Dayton Audio RS180S-8) that I tentatively plan on using with the ML panels. Two enclosures--each with a SL3 panel, and a linear array of six each 7" woofers (I almost hate to call a 7" speaker a "woofer", but Dayton Audio does). I'll let the Driverack serve as the cross-over and equalizer between the three subsystems. All of this might become overkill--will give it more thought, as I get closer to cutting timber.
 
Nelson, and all--thanks for your inputs. I'll probably use the F5 with conventional speakers, and use the Onkyo Grand on the ESLs in the other audio room....

Nelson--agreed, on the conservative listening levels. I'm the same--unless, of course, I want to fire up the Greatful Dead, Grand Funk, Vanilla Fudge, or Tower of Power to blow the dust of the rafters in the old listening room....(!)
 
wouldn't bridging be worst due to the impedance ...? cant imagine an F5 powering Apps..

and Current for the Apps ...

No problem with the Apogees, the F5 can work with a very low impedance speakers (1 Ohm) (If you choosen the adequate transformer) and have 10A peak per channel. Less impedance (More drive) = less heat :)

But one F5 isn't enough.

With two F5's in bridge, I believe that you can get almost 100W or more per channel, more than enough for a Stage or a Caliper. :violin:
 
7 midbass drivers..#!!.. Now we're seerious aren't we!.All you have to do now is roll off the panels at maybe 5K or maybe stretch it a bit higher and stick a DIY ribbon tweeter of the same height Ala Magnepan or similiar construction and you can rip...
The ML panels are clearly uncontrolled at the top end (serious slow decay waterfall plots at the top mean lost control of that diaphram althought it doesn't sound too bad considering the damage, but test instruments are to dumb to lie and that should be enough since others do better
Time align everything and you can wash up and go home!

Regards
David
 
No problem with the Apogees, the F5 can work with a very low impedance speakers (1 Ohm) (If you choosen the adequate transformer) and have 10A peak per channel. Less impedance (More drive) = less heat :)

But one F5 isn't enough.

With two F5's in bridge, I believe that you can get almost 100W or more per channel, more than enough for a Stage or a Caliper. :violin:

I would love to hear bridged F5 on calipers :D even if they only last 5mins..:p
 
Hi,

the ML-Panels are quite efficient. Driving them with audio trannies with transformation factors between 1:60 and 1:80, a HV-Bias of 1.5-1.8kV and X-over freqs of >300Hz everything above app. 20W(8Ohms) is sufficient for full stroke.
The typical problem with hybrid panels is not due to too low specced power of the amp, but its ability to drive a complex load stable. Also, the low impedance towards the upper bandwidth limit ususally represents no problem to a decent amp. Again, its the amps ability to drive severe capacitive loads.
This asks for capable power supplies and oversized current and heat paths to deal with the complex currents which may exceed the real currents alot.
The problem increases the better the audio trannys quality is. The original ML trannies were therefore deliberately chosen to be of very poor quality, which made the driving amp´s life a lot easier. Since this resulted in poor bandwidth, considerable amounts of equing were necessary. What saved the day was the inherent high efficiency of the panel, which after equing (that costed ~10-15dB!) was on par with the partnering bass.
Driving such a panel with a first class transformer much less equing is necessary and SPLs of >>90dB@4m are possible, which proves that rather low wattage amps may be fully sufficient.

jauu
Calvin
 
Calvin, how much of the decay trails are coming from the transformer vs. the panels?
I get their reasons on compromise but the top end load is still tough. My 50 watt Krell clone is not as happy as my 100 and 150 Krell copys are, but the 50 drives my Quad esls fine all around. You can just feel the juice necessary to make the SL3's sing properly.

So has anyone actually done what you suggested and brought both panels and new trannys together and shown the end results are superior? If so, I'd would be interested in modifying

regards
David
 
Hi,

every ESL panel exhibits a multitude of resonances. The most pronounced beeing the free air resonance fs which is due to the mechanical stretching of the diaphragm. As frequencies increase there´s first a range of resonance freedom until the wavelengths reach the dimensions of the segments. Then standing wave effects occur, which could be controlled by introducing damping. The use of hard materials as spacers/dampers makes things worse. ML gave up on soft spacer material in the 90´s and introduced ´clearspars´. A tightly stretched membrane, hold taut in a stiff frame made of hard materials...... no wonder the panels show many standing waves artefacts. The big Q is...does it influence sound? and if so ... does it influence in such quantities that it matters? Or is it rather just a measurement problem? I tend to the latter. Highs usually sound very well, integrated and natural with ESLs. If listeners complain about the highs of a panel its usually because of amplitude matters but not because of the sheer quality of reproduction.
I assume that the majority -if not all- those decay trails are due to the panel construction. Using a different tranny will not change the panel´s behaviour with regard to decay considerably. The main difference in using a different transformer lies in the amplitude- and distortion-behaviour.
Using a superior transformer design, you may gain a more linear amplitude response with lower equalization needs together with higher SPL and lower distortion figures. As a possible downside it may be more diffult for the amp to drive the panel properly, because of the larger phase shift and if You want to tweak an existing system You have to rematch the new higher efficiency of the panel to the bass.

see: http://www.diyaudio.com/forums/planars-exotics/45524-polarising-voltage-older-sequel-ii.html
http://www.diyaudio.com/forums/planars-exotics/64620-ping-calvin.html#post727647

jauu
Calvin
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.