AudioNervosa
Systemic Development => Speakers => Topic started by: Carlman on August 28, 2009, 11:37:55 AM
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I'm in the process of rewiring and considering a cap upgrade. I read great reviews about Duelund VSF-copper caps and thought, wow.. that sounds exactly like what I want.. They seemed a little pricey but I wasn't sure 'how pricey'.. but now that I've got the xo's out.. and I see I need a 47uF cap, they're in the $1,200 range, EACH.. in USD! Do people really pay that per cap? I mean wow. If I were to replace all the caps I have (bass and tweeter), that's 6 per speaker... even at 1,k per cap, that's 12,k... in addition to the cost of the speakers... which wasn't small change either.
Sorry if I'm late to the high-price-cap party... but I just needed to vent and wonder aloud at how that's even possible that people use these to upgrade speakers.... ?
-C
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There are 10 caps in the mid/high filter each speaker and 3 each in the bass filter. 13 caps per speaker. They are 4th order crossovers with some impedance or EQ correction. The stock parts quality offers a good upgrade opportunity. I think you would be surprised with the improvement, even with Jantzen caps and coils, which are still premium parts. Use mundorf silver/oil on the tweeter high pass if you want to get fancy.
Duelund makes aluminum caps too, a lot cheaper, but same order of magnitude. And they make silver plate caps too. Special order only :shock:
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That big cap is probably on the woofers, right? I would keep the one that is there and just look to upgrade the tweeter crossover caps. That's where you will get the biggest bank for the buck anyway.
If you really want to you could put a .1uF bypass on that big cap and get 90% of the improvement you would see with a full replacement. I would suggest using one of those inexpensive Russian Teflon's. It may or may not work, sometimes that bypass could bring too much to the top end and not sound correct at the crossover point. Your ears will have to be the judge.
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I put photos in the gallery... (http://www.audionervosa.com/index.php?action=mgallery;sa=album;id=2) You can see what we're working with... Rich gave me a great analysis of what he saw (crap) and I appreciate it! :) Thanks for your suggestions about the bypassing, Bob... I will check into it more.
Some curveballs to play with..
1 option: Go with an actively amped system.. I think this makes sense but I've never heard it or dealt with it.. so it's a complete unknown and a steep learning curve, which sounds fun.
2nd option: Create new crossovers, keep them external, leave the stock xo's as-is for re-assembly/resale
3rd option: Stick with the plan and just upgrade some parts on the existing board.
4th option... some combo of 2 and 3.
I have one speaker on the floor with its guts hanging out and the xo's on my desk... decision time!
-C
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Obviously...I'm going to follow this closely...since we have the same speakers :-k !
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That's a lot of parts, I'm guessing option 2/3 would be your best bet. One of the trouble with the good Jantzen's and Mundorf is the size. Both are double wound to cancel inductance but it also doubles the size for a given value.
The first thing I would do is draw up a schematic if you have not done so already so that you can determine which parts will have the most impact. At least the caps on the tweeter board look like polypropylene but kinda hard to say for sure.
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I'm taking my dissasembled speaker to our local xo master/guru Rick Craig and getting his opinion.. I'm fully capable of admitting when I'm in over my head! :shock: But at the same time I'm enjoying the learning! :)
Mike, I'm pretty sure I'll have to go outboard on the XO's... more to come on that.
So, I'll report more... and Steve, I'll be happy to let you hear what the improvements do.. Maybe we could do a direct comparison at some point... I did that once in the past with a couple pair of Usher 718's where I had the V-cap upgrade.. I think you were there, it was a long time ago.
I think the sub 1,k Usher's had a better xo design than these 15,k Piega's... so, I expect a bigger improvement but I'm not real pleased with what I've found so far... and some poor work has been identified by myself, Rich, and now Rick. The cabinet is great and the drivers are mighty fine... but I'm really looking forward to this tweak/complete rework now.
-C
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Taking them to Rick will no doubt guarantee a good result. :D
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First post here so I'll keep it short. :D
I looked at the crossovers and went over everything with Carol on Saturday. First listening was today. If Carl approves I'll blog here as I go.
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Welcome Rick. Glad to have you hear. Looking forward to your impressions.
Bryan
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Welcome, Rick! :)
I wasn't sure if you wanted to 'go public' with this project so I was keeping quiet. Blog away! You can even use my comments/replies in email.
I'm excited about what Rick's doing and he's already found all the issues I had and is planning on how to work it out with a completely new, outboard crossover for these speakers. I think the C8LTD's are great speakers but there has always been something holding them back.. and I'm starting to feel good about deciding to crack these babies open and take a peek.
Once these are done, (i.e. voiced, settled in/broken-in/etc.) I'd like to compare them to Steve's and hear what the real improvements are.
Thanks and welcome,
Carl
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Hi Rick!
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First post here so I'll keep it short. :D
I looked at the crossovers and went over everything with Carol on Saturday. First listening was today. If Carl approves I'll blog here as I go.
Welcome Rick, blog away.
charles
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Thanks for the welcome. Carl and I started with discussing how he wanted to improve the speaker and what things he liked about the sound. I tend to favor mods that just don't replace parts but also improve the execution / design of the crossover. In this case the crossover design is pretty complex, much more than you would typically see in a high end speaker. The parts quality was pretty much what is expected for a commercial speaker; however, the layout of the inductors could present some problems (mutual inductance). Small iron bobbin coils are also prone to saturation and the distortion from that smears the sound.
We talked about how much space would be needed for replacement parts and it became obvious that going outboard was the only solution. Fortunately the input terminals are bi-wire capable and the mounting plate will allow for a third set of terminals. Carl brought both speakers with one intact and the other open for inspection with the woofers and crossover removed. The construction of the cabinet is very good with excellent fit and finish. The first thing I noticed is that the crossover was so complex that you can tell this is going to be a difficult load to drive. Stay tuned...
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Hi everyone, this should be an interesting journey. Rick did an excellent job on my crossover design- seamless transition, smooth and still very detailed. Seems like a challenge to come in to an existing cabinet, drivers already there, and go at it from that angle. Looking forward to hearing the updates.
Rob S.
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It's amazing to me how quickly Rick figured out so many specific things that took me a long time to discover through listening. There IS a science to this stuff after all! :) Rick has pulled back the curtain and let me see into the workings which has been a fun learning experience. He explains why something is happening which is helpful when I marry the explanation to my experiences. And a greater understanding is reached! :)
Yes, it is very Zen-like... 8)
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Looking forward to hearing the updates.
Hopefully you can hear the finished product on your visit.... 8)
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I feel my pocetbook starting to pucker-up :(
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I haven't heard them yet, nor do I expect to for a while. I'm out of town Sat-Wed so I'm hoping to hear them when I get back.. I'm curious and excited and trying not to let my hopes blossom into unrealistic expectations. I think it's probably like being in the waiting room during your wife's breast enlargement surgery. ;)
-C
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I'm posting a timeline and emails from Rick (with his permission):
This is the initial assessment after Rick had some time with the speakers:
--- On Mon, 8/31/09, Selah Audio wrote:
Carl,
I spent some time listening to the Piega today. Here's a
few notes I made on the sound.
1) Driver integration needs some work. I could hear
shifting of sounds vertically when there was a transition in
frequency from the lower to upper mids. The mid/tweeter
panel at times really seemed to overwhelm the output from
the woofers depending on the source material.
2) Overall balance on some recordings was good but on
others the top two octaves were too prominent. Everything I
played is mixed fairly well so I could see where poorly
recorded stuff could drive you out of the room with this
speaker.
3) Hardness / edginess / congestion was evident at times in
the upper mids / lower treble. Again, the speaker isn't very
tolerant in this area but I had suspected that would be the
case given the mid and tweeter design.
4) Bass at times was bloated and lacked pitch definition.
There seemed to be a resonant mode - not sure the reason for
that but the measurements will help reveal the source of the
problem.
5) Integration of the mid to the tweeter was good and the
coincident layout is working well. Vertical dispersion for
angles above the tweeter axis was pretty good.
6) Lower mids were lacking "body". Some of this may have
been intentional in the voicing the designer prefers. I also
suspect the crossover to be a problem in that area as well.
7) Horizontal off-axis response was not as good as what I'm
used to. In the top octave the tweeter's width affects that
so there's not much you can do with that (not that it's bad
but I've been listening to the Raal ribbons quite a bit
lately). Once I measure I'll see if the crossover is an
issue as well.
8) Sensitivity is low and this speaker really sucks power
from the amp. No way it's close to being 89db. Like we
discussed I think the crossover is sucking some of the life
from the speaker with inductor losses and phase angles.
Overall I think there's definitely room for improvement and
redesigning the crossover should help improve most of these
areas.
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Another email from Rick with technical measurements and values:
Lots of testing today. Explanations below:
PWFREE - free-air test of the woofer. Fs=41.5hz which indicates their 28hz
claim for bass extension is a little "optimistic"
(http://www.audionervosa.com/MGalleryItem.php?id=160")
PUWNEAR : Uppermost woofer measured nearfield. The port contribution won't
show here so the extension is only 55hz/-3db and 41hz/-10db
(http://www.audionervosa.com/MGalleryItem.php?id=157)
PLWNEAR: The bottom woofer summed with the port. 48hz/-3db and 31hz/-10db
which is normal given the Fs measurement of the woofer. Not bad extension
but falls short of what I would expect for a speaker at this price.
(http://www.audionervosa.com/MGalleryItem.php?id=156)
PONAXIS: On-Axis measurement, mic at tweeter height. The elevated upper
midrange and rising response in the top octaves that I noted in listening is
evident here.
(http://www.audionervosa.com/MGalleryItem.php?id=158)
POFFAXH: Response is pretty flat a 30 degrees horizontal off-axis. Typically
this would be tilted downward a little as you move up in frequency response;
however, since the on-axis has a rising response the off-axis has more
energy. In a room with little or no treatment and / or walls that are close
on each side the speaker will sound too forward / bright.
(http://www.audionervosa.com/MGalleryItem.php?id=159)
POFFAXV: Vertical response on-axis at 1M. Measured from the top woofer to
about 6" above the top of the cabinet. Very little change at all angles and
shows that the concentric mounting of the tweeter works well.
(http://www.audionervosa.com/MGalleryItem.php?id=154)
PIEIM: As expected from looking at the crossover the impedance shows a
difficult load with large phase angles. Given the low sensitivity this is a
pretty difficult load and high current solid state amps will fare much
better than tube amps.
(http://www.audionervosa.com/MGalleryItem.php?id=155)
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Even just biamping the ribbon array my 100W tube amps did not fare well.
It gonna be much better than a boob job. Because you're gonna be able to play with them whenever you want. :yay2:
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When you modify a speaker you never know what to expect. I've had a few unusual speakers come in from two other manufacturers that reside at Audio Circle. Sometimes I tell the owner it's not worth it as was the case with one where the driver combination and design execution sucked really bad. I felt for the owner but basically told him what the problems would be before I even measured it.
The second one was made by a company who gets quite a bit of hype on the net. Upon removing the drivers I found out that the woofers didn't match. From the outside they look the same but apparently they never bothered to do incoming inspection or test them before shipping. After measuring the response of both I found that the wrong woofer had been used for the crossover design and so the crossover wasn't optimal for the cabinet (sealed cabinet but woofer intended for a ported cabinet). I told the owner that he should be compensated because he paid for expensive crossovers that were unusable with his specified drivers. When confronted with his error the owner of the company refused to give him a refund - so much for great customer service!
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The replacement parts arrived today :)
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Yay! Really looking forward to hearing them... I'm all excited like a little kid! ;)
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Yay! Really looking forward to hearing them... I'm all excited like a little kid! ;)
The initial listening test started today. Originally the crossover had 63 components (19 inductors, 24 caps, and 20 resistors). Right now the new crossover has 12! The first change is a huge increase in sensitivity. Only one resistor! Overall response is more linear, greater dynamics, and a cleaner presentation. Now on to fine-tuning the voicing.
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I always knew in my mind that the Piega crossover was the real culprit in how it sucks power down like nobody's business.
I've thought about upgrading mine for a long time, but I have always been terrified of how it would turn out. I just assumed the extreme complexity in the crossover was necessary to match the wildly different drivers. I will be anxious to hear the result.
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I'm with you guys...if a substantial improvement, then this may be in my future, as well 8).
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Carl, think you'll have these by Saturday or Sunday?
Also- did you go with Rick's recommendations on parts for the crossover?
Rob S.
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Yay! Really looking forward to hearing them... I'm all excited like a little kid! ;)
The initial listening test started today. Originally the crossover had 63 components (19 inductors, 24 caps, and 20 resistors). Right now the new crossover has 12! The first change is a huge increase in sensitivity. Only one resistor! Overall response is more linear, greater dynamics, and a cleaner presentation. Now on to fine-tuning the voicing.
63 to 12 - that's quite a difference Rick. If it can be made balanced, I'm all for the KISS principle.
Bryan
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Carl, think you'll have these by Saturday or Sunday?
Also- did you go with Rick's recommendations on parts for the crossover?
Rob S.
Rob, I don't know... Rick's still voicing and such so I don't know the ETA yet. I hope so as it'd be nice to have you by to hear my room with the 'real deal' speakers. But at the same time I don't want to rush anything.
-C
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I always knew in my mind that the Piega crossover was the real culprit in how it sucks power down like nobody's business.
I've thought about upgrading mine for a long time, but I have always been terrified of how it would turn out. I just assumed the extreme complexity in the crossover was necessary to match the wildly different drivers. I will be anxious to hear the result.
Actually it wasn't that hard to integrate everything; however, if I were to start from scratch I would've designed the woofer section differently. I came up with an unusual solution to match the woofers to the planar drivers and it turned out very well. The crossover was more complex than anything else I've ever seen, maybe with the exception of some older Thiels. The new design is *much* more amp-friendly.
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Carl, think you'll have these by Saturday or Sunday?
Also- did you go with Rick's recommendations on parts for the crossover?
Rob S.
Right now I have one speaker stock and the other with the modified outboard crossover. I'll set it up so Carl can compare the two. The modified crossover has Clarity PX and SA caps but he can choose other caps in the mid and tweeter section if desired.
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Very interesting. Impressed by the professional approach and methodology. Rick , have some Maggie 3As to play with. When I'm ready you will be the man. Like your style.
charles
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We heard the first draft of the new crossover today in one speaker only, compared to the other speaker with stock CO, playing Carl's usual audition tracks. I thought it was no less than an amazing transformation. Much cleaner, less grunge, clearer tone, much more open. The difference in bass quality is amazing. It is a truly high end speaker now. I can't wait to hear them in stereo with final tweaks. Thanks for inviting me Rick and Carl.
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Yes, it's a transformation.. and the speaker has changed its personality a bit.. it's more 'grown up' sounding... There is much more detail at every level and there is no (audible) distortion. The downside to this is that it somewhat requires excellent recordings. You can hear every nuance of everything. I heard new things I've never heard before yesterday... even in that Peter Gabriel 'Growing Up' song... which we've all heard too many times. ;) My reaction was, "oh, so that's what that is"... and wow, that recording is weird... as was most of the stuff I brought.. (mostly over produced pop crap). Sufjan Stevens recording choices were more evident.. with this nasal-sounding mic and for the first time I could really hear how off-key the violinists were. They're bad.. and I can't imagine it was intentional. It was super easy to pick instruments and hear the complexity unfurled. It gave a more 'you are there' presentation. There was definitely more emotional impact also. I can't wait to hear the pair in my room...
It was very cool to go back to the stock speaker and hear the changes. There was a familiarity there which I enjoyed... there is a little distortion in the upper mids that sweetens the highs a bit in the older design... but that's about all I can say good about the older design after hearing the new one. The new design is just heads and tails above in every way.
I decided not to change anything Rick had done until I'd lived with them a couple of months. It's a big change and I didn't feel qualified to tweak Rick's design after listening to 1 speaker in an unfamiliar system.
I'm hoping to get Steve to bring his C8's to compare directly when I've got these setup in my room so we can hear the difference. I'll have a G2G of course. :)
This change will take me further into the ability to hear the differences in components.
Charles is correct about working with Rick.. a real professional and a class act all the way... and he knows his stuff.
-C
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Carl is on the way home with his modified set. :D
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Now I'm just waiting for wife and friends to get home to help me move them to their home! :)
They sounded really good at Rick's... can't wait to get them into the big room.
It has been a pleasure doing business with Rick, from beginning to end.. thank you!
-C
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Come on, big guy!!
You know that you are excited enough that you can carry them down all by yourself :rofl:!
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Carl is on the way home with his modified set. :D
Hi Rick...
Don't know if you've checked out Carl's new room, but it is a "must hear"...really nice.
Hope to see you again in Oct. in NYC...too bad no RMAF this year.
Chris
Enjoy Carl..... :beer:
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They are in and playing some reference tracks.. and oh boy.. you guys are not going to be dissapointed. It's the kind of improvement that builds and builds.. very satisfying. :) Also, the personality of the speaker is intact, which was one of my bigger concerns. I'm still in the 'new' phase.. and will let these play overnight.. and get others' opinions tomorrow.. but I'm extremely pleased with the upgrade.
-C
Come on, big guy!! You know that you are excited enough that you can carry them down all by yourself :rofl:!
You know, I almost did.. had I thought about it more, I think I would've... I have a hand truck.. but the way the crossover was dongled to the speaker made me nervous doing it alone... plus uncrating was a 3 person job.
Note: It would be a good idea to have the external crossovers removable from the speaker. ;)
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I've heard serveral of Rick's designs before and 1 of them in my own room. Never heard anything that didn't have a ton of potential.
Waiting to hear your impressions after a couple days Carl
Bryan
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Carl is on the way home with his modified set. :D
Hi Rick...
Don't know if you've checked out Carl's new room, but it is a "must hear"...really nice.
Hope to see you again in Oct. in NYC...too bad no RMAF this year.
Chris
Enjoy Carl..... :beer:
I hope to check it out in the near future. I'll be in NYC after the show if you can make it on the 18th.
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I'm pretty sure we'll be meeting on the 26th to compare the C8 stock vs. upgrades... that's this coming Saturday.. I'll post it in the other thread about the meet once I confirm with Steve.
So far I'm still liking the sound.. and realizing more and more I'd like a sub.. or 2. The percussive thud is just missing.. always has been but it's more noticeable now that I have the rest of the musical structure intact. It's a very cohesive sound.. I just need a little more time to get them positioned properly. Piega's do not sound good until they're in THE position they want to be.. and that's that.
I think I'm getting closer but it'll take lots of experimentation before they're 'right'.
-C
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I'm pretty sure we'll be meeting on the 26the to compare the C8 stock vs. upgrades... that's this coming Saturday.. I'll post it in the other thread about the meet once I confirm with Steve.
So far I'm still liking the sound.. and realizing more and more I'd like a sub.. or 2. The percussive thud is just missing.. always has been but it's more noticeable now that I have the rest of the musical structure intact. It's a very cohesive sound.. I just need a little more time to get them positioned properly. Piega's do not sound good until they're in THE position they want to be.. and that's that.
I think I'm getting closer but it'll take lots of experimentation before they're 'right'.
-C
First off, GOOD LUCK. Carlman those new caps and things need to break in a bit especially the woofer section. Give them some serious time before you add subs. The caps alone need 200 hours plus to settle . If they are Teflon caps longer. The drivers are well broken in so no problem there. Live with them for a while.
charles
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Rick used 'Clarity' caps.. and I'm sure they'll open up more with break-in.. but I don't know how much. They're of reasonable size. Steve took some photos of the crossovers.. maybe he'll post them here?
-C
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Any updates?
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Still lovin' it. I've done some tube rolling and things just keep getting better. I just moved my speakers an inch and need to re-measure everything again to get them dead-on.. but I haven't really wanted to change anything yet.. I still want to add subs, though.
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Any pics or a description of the modifications?
Thanks,
Mike
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I came here to make a quick update and noticed I'd missed your question, Face.. I thought someone shot some at our big comparison/G2G with Stereofool's stock C8 Ltd's. It's nothing spectacular.. For now just imagine point to point wired caps and inductors, in a big black box. ;)
Back to the update.. I decided to pull down the tweeter a touch because it's just too harsh/hard for my listening/musical tastes. I wanted to be sure I was doing it right so I enlisted the help of Richidoo. The friend that he is, he drove here w/ soldering gun and all sorts of tools and toys.. It was basically minor surgery, just add a resistor where Rick Selah described.. but crossovers just aren't my realm... In any case, Rich pretty much just added them.. and thanks a million!
My system 'should be' laid back.. I have a tubed non oversampling DAC, tubed pre with romantic tubes, and McIntosh amp.. But it wasn't. It did/does a lot right, though. Now it's actually a little laid back, like it 'should be'. 8)
Many songs that were previously unlistenable now are.. and the detail is still there. I can listen 'into' the music now. I get to hear the intent of the music... I can reach out and touch the soul. It's like the singer, cymbals, and high hats took a half-step back. Also, it sounds like the bass is a little louder which I like.. since I can't afford subs yet. ;) I'll continue to get used to these changes over the next month and see how it goes. I might reduce resistance a little to get back a little bite but maybe not. I think it sounds pretty much like it should given the electronics in front of the speakers.
Do resistors break in? Seems like it's sort of changing as I listen.. not sure if that's me or the new thing, though..
Thanks again to Rich!!!! :thumb:
-C
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Resistors do break in, but nothing like the sometimes endless process with caps.
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You're more than welcome Carlman! They sound a little laid back for me, but the edge is polished off nicely, which fits your listening style better. Maybe less singeing the eyebrows now. :D I prefer it as it was, dead flat for violin excitement. It's only a smidge and on attitudinal rock it is welcome.
If you want a little more bass, you could pad the mids with the 2 ohm, then pad the tweet with the 4ohm. Then M andT stay as they are now but the bass is relatively louder. You got the parts, might as well try it.