My_Ref Fremen Edition RC - Build thread

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If we bi-amp, it will be passive only, no messing with xovers other than an added sub. I know that's not ideal, but these speakers are too special to modify in any way, and they're already set-up for bi-amping. The Aragon could run the low end with more control and depth. I'm not sure that is absolutely necessary or worth the added complexity and expense, but my friend is interested in ultimates, not compromises. The speakers, if powered properly, are nearly ultimates. The FE's on mids and highs would be superlative.

Peace,
Tom E

Of course, all of us are driven by curiousity. So I read a Stereophile review of the Andra IIs to learn more.

First of all, it's nice to see they are using Dynaudio drivers for the tweeter and bass speakers. As you know, my speakers are DIY with Dynaudio drivers and I like them a lot.

Next, you can only see one 12" bass speaker per channel because the bass speakers are put together in isobaric configuration.

Finally, according to Stereophile, you should be able to do what you suggest with FE's on top and the Aragon on bass. Not only are they bi-amp ready, but they claim that there is no electric crossover between the bass and mid speakers. In other words, they developed the mid range boxes to compliment the high frequency roll-off of the bass speakers.

As you say, the only thing you would have to do is tweak the output levels between the bass and mid-high sections while bi-amped. An L-pad built from nice quality power resistors should do the trick without messing up the sound. If it were me, I would keep the combined input impedance of the louder section the same as single amped and keep the series resistor values as low as possible to avoid raising the Q of the speaker. Since a fair bit of power would be going through them, something like Caddocks with heatsinks might be a good place to start.

Sounds like a fun project.

Jac
 
...... It takes a big, sealed sub to really control low tones. In fact, he already has an okay sub, but we are not yet trying to optimize anything except the FE's. The two 12" woofers in each speaker are plenty for now. ....

I know we might be talking in two different directions (Sub vs. Bi-Amp), but there is an alternative to the traditional big box sub. I used this massive magnet driver to build a Sunfire Clone. It is tight, powerful and goes deep combined with this Bash Amp. It's currently in a BR enclosure - again designed by Paul C - and is part of the Denon HT 7.1 system. I'd be very interested in adding the Sunfire type box to an FE based setup even if it required some kind of piggybacking with an additional FE.

It all gets somewhat complicated, and we are talking about a relatively small and infrequently needed enhancement to the FE presentation, but I'm wondering if a new separate thread for speaker integration - including XO work - with the FEs might be in order.

What say the masses???? :judge:
 

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I'm wondering if a new separate thread for speaker integration - including XO work - with the FEs might be in order.

What say the masses???? :judge:

I think it would be interesting to know what other builders are using for speakers, whether DIY or commercial, what types of drivers, what size, sensitivity etc. In my system I almost exclusively use AMT monitors and a bash powered sub with the FE. but sometimes I swap in KG4s just for a change of pace. The kg4s dont need a sub, but they dont have the perfect top end that the AMTs do. That being said I think it is worth discussing our speakers, of all the amp tweaks discussed they will all sound different to everyone based on their speakers.

On a side note I am collecting the parts to build a pair of cornerhorns to use with the FE. The bass drivers showed up yesterday.....Eminence omega pro 15A. I really had not thought about how big these were until I saw them. Oh my. I am hoping to no longer need the sub:D
 
Hey Will,

A corner horn. Cool! Look forward to hearing how you like it.

My FE's are powering DIY sealed 2 way towers with Dynaudio D28 tweeter and Dynaudio Esotec 17 LQ as mid-woofer. The efficiency is about 86 dB which is typical of Dynaudio drivers with the 75 mm diameter coils and aluminum coil wire. The woofer has pretty good bass extension for a 17 cm driver, but the deepest bass is rolled off a little due to the small woofer. It's hard to believe that I built those 15 years ago, but they still sound good.

Under normal conditions, I have a DIY subwoofer with acceleration feedback control filling in the bottom end, but I've been updating that and just listening to the FE's for more than a year. I don't feel like I'm missing much.

The subwoofer has an enclosure that is a cylinder cast out of concrete with the ends made of 38 mm thick MDF. The driver is a down firing NHT 1259 12" subwoofer with a modified dust cap to mount the accelerometer. The feedback control is on a DIY board using opamps at line level and the power amplifier was originally a Randy Slone 500 Watt MOSFET amp. I am in the process of replacing the Slone with an Aussie Amp module.

Of course, the list of started, but unfinished projects is endless, but that is what I am listening to now.

Jac
 
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Dears, just to say i had the luckiness to meet Dario today. Such a passionate fellow. He explained me his journey to push further the sound of his fab myref. A very enjoyable afternoon. Thanxs Dario and was really nice music the one i heard.Ciao to all of you guys, apparently in his same boat.:)
 
OT Alert

Not much interest in a FE/Speaker/XO thread so I'll just post a couple quick pics of the rig for my tweaking. I placed a ridiculous number of terminals so every component could be swapped for comparison. The parts shown are not the base XO where tests will start, but were used for spacing purposes needed for the largest items. The Obbligatos and "K"s Jac sent are enormous.:eek: R=Bass, Cntr=Mids, L=Tweets

I'll report back on progress in a few weeks.;)

(Upper right - pair of Russ White V 1.2 amps to be included in tests)
 

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Bob,

No lack of interest, but this is an old thread where few are watching and slightly side topic seems like fair game, as long as Dario doesn't mind.

By the way, I missed typed in my crossover discussion. I am using Caddock MP930, just like you, not the MK132 earlier stated. I went ahead and put a heatsink on mine because I had them laying around, but I suspect that I don't need the heatsink at all. As you put your MP930's in with your crossover, please report if they get warm enough to worry about.

By the way, isn't it the Audyn Plus at 22 uF that was the very largest cap?

Jac
 
Yet another off topic

Dario,

I have heard Bob and others say that they like Uriah's Lighter Note attenuator. It may have been in reference to other amps. Have you heard an LDR attenuator with a My_Ref amp? If so, I would like to hear your opinion. I have been thinking about in input chain and trying to keep it simple rather than convenient. I was thinking that an LDR approach might be the fewest components in the signal chain and it seems to me that the My_Ref amp rewards clean and clear signals. From my reading online, it may be that an LDR attenuator would be simpler and cleaner than even the best potentiometer. Any thoughts?

Although I specifically asked Dario's opinion, I would love to hear other opinions and experiences.

Jac
 
I have heard Bob and others say that they like Uriah's Lighter Note attenuator. It may have been in reference to other amps. Have you heard an LDR attenuator with a My_Ref amp? If so, I would like to hear your opinion.

Hi Jac,

I've had an LDR attenuator (one of the first version of Uriah's ones) and it sounded really clean, pretty transparent.

But it had some drawbacks (none of them directly related to sound but I found them annoying):

  • you can't have complete attenuation, you'll have some output even at minumum
  • at least in my case, LDR have been fragile, I've fried mines (and the attached DCB1) with static from hands.
I have been thinking about in input chain and trying to keep it simple rather than convenient. I was thinking that an LDR approach might be the fewest components in the signal chain and it seems to me that the My_Ref amp rewards clean and clear signals.

A LDR attenuator is no different than a plain pot in this regard.

From my reading online, it may be that an LDR attenuator would be simpler and cleaner than even the best potentiometer. Any thoughts?

Maybe but the difference from the smd attenuator I often suggest was not that big.

I don't have a direct comparison experience but the TKD pot I'm using now seem pretty similar to the LDR attenuator from what I can recall.
 
Thanks Dario.

The LDR is interesting technology, but you have pointed out some things I didn't know before. Nice to hear the comparison with the TKD too.

Bob was nice enough to lend me a Lighter Note in response to my question. In the near future, I hope to have a personal audition of several attenuator/preamps. I hope to compare a plain pot (an old and rather plain Alps, not a TKD), the digital volume control on the Squeezebox, the Lighter Note, and my Relaixed2 preamp (stepped attenuator switched by relay, plus buffer). At the moment, I'm listening to the Relaixed2 and it sounds good, but I am curious how the sound of the others will compare.

Jac
 
.......
I've had an LDR attenuator (one of the first version of Uriah's ones) and it sounded really clean, pretty transparent.

But it had some drawbacks (none of them directly related to sound but I found them annoying):

I loaded him up with both the basic Lightspeed and the LN. ;) The only slight annoyance I've experienced is a small horizontal shift on big movements of the volume pot. Both versions have a balance pot to compensate but it's not needed that often. While checking out the LN before shipping, I did notice a tiny lag in the balance function. Not a problem but interesting, something that became apparent only at that extreme near field position.

Who listens at complete attenuation?

Using series connected series LDR elements and parallel connected Shunt LDR elements combined with ultra low operating current gets beyond -80dB ref full volume.

This is kind of an old story/debate I have with myself, but as someone who currently uses PC/digital as a source 95% of the time, I have a direct link between the DAC and the power amp. There is a very small compromise using the PC drivers for volume control but it's acceptable for non critical listening. (plus it allows complete system function control from my phone :D). The volume is always up a little and signals when the rather long PC boot sequence is finished.

One of my major spring projects is to resurrect the vinyl playback system which will require putting a discrete device back in the chain. I suspect it will be the JC-2 Pre with the LN as it's volume controller. That worked out quite well in the integrated build from a couple years ago.
 

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Who listens at complete attenuation?

Using series connected series LDR elements and parallel connected Shunt LDR elements combined with ultra low operating current gets beyond -80dB ref full volume.

I was curious about Dario's comment as well. As an experiment, I set the Relaixed2 at a good listening level, then reduced to the lowest level I could hear from my listening position. Since the Relaixed2 has discrete, known volume steps of nominally 0.95 dB per step, I was surprised that I could still hear the music at about 44 dB below listening level or 59 dB below ref full volume. Of course, the full 80 dB that you described would be inaudible, but I appreciated that two steps down on the Relaixed was full mute. I agree with you that I will never listen at such low levels, but I also understand that a fully muted option might be nice to take a phone call or converse with someone else in the room. I could see where an LDR with a switched full mute option might be an interesting idea.

Jac
 
Who listens at complete attenuation?

Using series connected series LDR elements and parallel connected Shunt LDR elements combined with ultra low operating current gets beyond -80dB ref full volume.

Hi Andrew,

Obviously no one... but the one I've owned didn't attenuate so much, the audio was clearly audible.

I agree with you that I will never listen at such low levels, but I also understand that a fully muted option might be nice to take a phone call or converse with someone else in the room.

Exactly :)
 
One of my major spring projects is to resurrect the vinyl playback system which will require putting a discrete device back in the chain. I suspect it will be the JC-2 Pre with the LN as it's volume controller. That worked out quite well in the integrated build from a couple years ago.

OT: Bob , did you look into the various arduino-controlled attenuators that allow re-calibration of the LDRs and volume level / resistance control by software?
 
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