Ardent Speaker Camp

[cjd]

Could be. There's a mental shift too, lots of people start looking at early retirement, worrying about the "non-working" future. It used to be living to 60 made you ancient.

[JonMarsh]

Could be. There's a mental shift too, lots of people start looking at early retirement, worrying about the "non-working" future. It used to be living to 60 made you ancient.

Well, in a day and time not so long ago, late 40's or early 50's was typical...

These days it's different, but still requires an individual commitment to maintain lifestyle quality.

[Paul W]

Tail end of the bath-tub curve for inherent defects or lifestyle issues?

Too many near misses over the years, so I consider myself extremely fortunate to greet 2010. The "excitement" tonight will be cajun food.

[JonMarsh]

Hey, there's a morbid sort of thread we could start, each of our "near misses" - I understand that feeling, had more than a few, especially being a motorcycle rider- but other sorts of near misses, too. Without modern medicine, I doubt I'd be around, or I'd be so debilitated I'd be useless. Quite a contrast to the actual state of affairs, where I'm actually in better operating condition for the most part than ten years ago- partly because some things have been "fixed" in the meantime!

We undoubtedly each have our blessings to be thankful for... even if the finger joints do click now in the morning as a result of building the Ardents!

[mkc]

Hi Jon and all

Happy new year. We got a little more than 3 hours to go of the old year.

Now, if I just could get your attention to the SS discovery series of units... I have to find a way to buy that ACO mic.

Best regards,
Mogens

[JonMarsh]

Which of the Discovery series interest you the most?

I've got several designs underway with the D2608/9130.

The 10F/4424G looks like it could be a very nice mid priced midrange unit (well, my idea of mid price- it might be high end for others) - it appears very well behaved for the range 300 Hz to 3 kHz, allowing some room for the required overlap on top and bottom. This is one of the more intriguing (to me) new mids, but I didn't want to broadcast that around until I got one to evaluate-

The 18W/8434G00 looks promising as regards the basic characteristics; one could hope for a touch more Xmax, here it has to go up against the Seas ER18RNX. It would be interesting to see how they compare on HD. For a single driver MT, the 18W/4434G may be a good choice, again, only being hindered by the 4.2 mm Xmax compared with 6 for the competition. If it has a lead in midrange distortion, that might make the difference, but the VC impedance curve doesn't look like special measures are taken to reduce inductance, so I'd expect a rising distortion plot due to inductivity modulation above 500-600 Hz. Of course, I could be wrong, just informed speculation.

Have you seen any published test data on these drivers?

[cjd]

We undoubtedly each have our blessings to be thankful for...

Ahh, perhaps I have something to look forward to after all. . .

[mkc]

Hi Jon,

I have been wanting to try out the D2608/9130 (108$ in Denmark), but haven't got around to it yet. The old Peerless version was a little cheaper and can properly still be had.

I agree with regards to the 10F/4424G. I have also had my eye on that and I believe it to be intended as a mid priced unit, though that mean 114$ here in Denmark. Well, I expect the whole Discovery series to be intended as mid-priced. Basically it would be interesting to see measured data for all of the Discovery units, just to get them characterized, but I have not seen anything other than mnfg. spec.

The SEAS unit is nice, despite the 140$ price tag here. Of course, it pays to buy them else where here in Europe, if one needs more than a few units as that helps even out the shipment costs. That also apply for ScanSpeak Units. :x

Happy new year,
Mogens

[JonMarsh]

The 10F/4423G could wind up being a preferred midrange choice for a lower cost version of the Ardent, just to wrap the discussion up back on topic!

European distribution and pricing is always something that has us NAFTA guys scratching our heads- it seems to me that in a lot of areas, the European consumer gets rather shoddy treatment price wise. And being able to get Scanspeak or Seas kit cheaper from a distributor outside of Denmark is a clear example...

[Carl V]

The 10F/4423G could wind up being a preferred midrange choice for a lower cost version of the Ardent, just to wrap the discussion up back on topic!

European distribution and pricing is always something that has us NAFTA guys scratching our heads- it seems to me that in a lot of areas, the European consumer gets rather shoddy treatment price wise. And being able to get Scanspeak or Seas kit cheaper from a distributor outside of Denmark is a clear example...



Price control, cost shifting....not unlike health care or Perscription drugs.

[---k---]

Please, no politics. Thanks.

[evilskillit]

Please, no politics. Thanks.

Well... Can we talk about religion then? Just Kidding, the last thing anybody wants is for this thread to derail. I'm with K.

[JonMarsh]

Ss D3004-6640

How did that old comedian's signature routine go when triggered by the wrong words or situation?


"Slowly I turned... step by step... inch by inch..."


Well, I'm not angry about testing drivers, really I'm not, except maybe occasionally the ones I spend buckets of money on- that's always a crap shoot. Better to do like John Krutke, I guess, and test other peoples stuff. :W

in my case, I think it refers more to how slow I am getting things done when there's a lot of stuff on my plate and it feels like I'm wading through molasses in slow motion.

ANYWAY..., without further silliness, I'm thinking this may be the tweeter I wind up using in the Ardent as I finish it off.






D3004-6640 Beryllium Family of Curves, 0 Deg, 10 Deg, 20 Deg, 30 Deg




D3004-6640 Distortion, 2.83V Drive

Ideal? No... but I'm going to do some listening to them in comparison to the D3004-662001 and 662000, and see what I think- you see, to my ears, the latter are a bit too hot in the 10-20 kHz octave -

For the Be tweeter, not the relative absence of a high Q breakup peak- yes, there is one there it seems around 35 kHz, but the Q is more on the order of what you see with ceramic dome tweeters from Accuton, not so much like the higher Q resonances from typical metal dome tweeters. With my prejudices, I tend to think that's a good thing.

Here's the 662001:


D3004-662001 Curves


D3004-660000 Curves



D3004-660000 on axis

These were all measured on the same baffle with the same mic, amp, etc.

Re distortion, the D3004-6662001:



they're both characteristically Air Circ tweeters, with the higher HD2 (sweetener to add some harmonics?) though the 6640 seems cleaner in the upper octave. Won't add as much zest to the Zildjians, I guess.

Probably I've spent too much time listening to the D26NC55, which while it has it's sins of omission, has surprisingly little in the way of sins of commission. To my ears, anyway- YMMV.

Perhaps it's in the faceplate design differences, even. I dunno.... need to do some listening.

[Carl V]

Please, no politics. Thanks.

gotcha.... I never meant for it to become political. Only,
that businesses often cost shift. I avoid politics & religion
on these sites.

[JonP]

Tony's execution (or hired execution) is pretty interesting, but the crossover looks over the top even to me, though leaving out some things that shouldn't be left out - like Midrange LCR zobel!

I think this concept has some room in it, and the RS270 is one of the drivers I planned to analyze for this concept. There are other scanspeaks that would work, too.

Nice work Ryan, but let's see if we can split the difference in a creative way during the next couple of weeks? I hope no one minds if I use a different tweeter... :W

All in favor of a completely re-worked design with NeoD CC crossover and a reasonable budget, raise your hand and say "Aye".

BTW, wanted to get my AYE! in...

Still have my RS52's, never got a pair of DN26's (a shame, I even have a pair of HiVi 6.8's, wonderful gift, half needed for the original NeoD) So is this NeoD CC II, or the Baby Duelund? Or does it matter? :B Heck, you even got me with the Modula MT II, as I have some of those waveguides languishing around here someplace...

[JonMarsh]

With a single 8-10" woofer, I'm calling it the BD Monitor- Baby Duelund.

There is a NeoD CC MkII in the works, just got those drivers in, including the D2004/6020 - need to measure those soon, but need to cut a new baffle. I just re-organized the measurement setup, a new shelf unit that makes things more convenient and tidy, and some new test stands and a second turntable.

[ergo]

Jon, would you please elaborate a bit on the tools and techniques you use for a speaker set measurements.

I see from above that you mainly seem to use Fuzzmeasure for measurements. There are some questions that I have though.

* Do you use a measured phase response or create a minimum phase?
* If measured phase then where do you usually start the gating window.

Sometimes it is set to most maximum impulse peak - this is easy to determine for tweeters, but not so for midbasses and woofers as the impulse is not as sharp and maximum is harder to determine.

Sometimes the marker is set before impulse, but with moders ADC-s and DAC-s there is usually pre ringing thus again hard to determine where to set the marker.

* How do you get the low frequency part for woofers / midbasses. The usual near and far field + simulating the baffle step and combining the two? If so, which tools you consider good to determine the baffle diffraction and baffle step?

***

There is an interesting paper from 2008 from Juha Backman for getting better low frequency extension in non anechoic room measurements.

http://www.aes.org/e-lib/browse.cfm?elib=14483

I've been planning to try that approach, but have not got around to it yet.

[JonMarsh]

Jon, would you please elaborate a bit on the tools and techniques you use for a speaker set measurements.

I see from above that you mainly seem to use Fuzzmeasure for measurements. There are some questions that I have though.

* Do you use a measured phase response or create a minimum phase?
* If measured phase then where do you usually start the gating window.

Sometimes it is set to most maximum impulse peak - this is easy to determine for tweeters, but not so for midbasses and woofers as the impulse is not as sharp and maximum is harder to determine.

Sometimes the marker is set before impulse, but with moders ADC-s and DAC-s there is usually pre ringing thus again hard to determine where to set the marker.

* How do you get the low frequency part for woofers / midbasses. The usual near and far field + simulating the baffle step and combining the two? If so, which tools you consider good to determine the baffle diffraction and baffle step?

***

There is an interesting paper from 2008 from Juha Backman for getting better low frequency extension in non anechoic room measurements.

http://www.aes.org/e-lib/browse.cfm?elib=14483

I've been planning to try that approach, but have not got around to it yet.

I have CLIO, Praxis, and Fuzzmeasure, but mostly use the latter lately. I like the graphing and general capabilities, and find it very productive with my working style, especially as how I can combine a variety of measurements in one file.

In Fuzzmeasure, there are many options for how to proceed, as you have full gating control for the impulse equivalent (though like Praxis it uses a sine chirp as the stimulus), and several window filters available- rectangular, Hamming, Half Hamming, Hanning, Half Hanning, Bingham and Half Bingham; for in room speaker measurements, I prefer Half Hamming, as you can use moderate length windows that preserve some low frequency detail while rejecting a lot of upper frequency reflections; Praxis has a similar mode.

Low frequency performance beyond 6-7 milliseconds is just as dependent on room placement and room characteristics, and that's what you actually have to live with, so I'm not really a fan of spliced full range measurements, though I usually spend some time looking at extended range nearfield measurements and measuring ports output (when present) to see if things are playing as expected.

For example, this measurement is in room, 1 meter on axis, with a moderately long window, but as the port was partly blocked by cables, I wasn't really too concerned about measuring the LF behavior below 40 Hz, and subjectively, the speaker had pretty extended bass, and very articulate - but the ripples in the response between 60 Hz and 1 kHz reflect a combination of floor, ceiling, and probably wall bounce, too- which you have to live with for a speaker in a real room.



In the design phase, I save a copy of the measurement of each driver as a minimum phase measurement, and I also measure the system with all drivers driven simultaneously full range, then in LspCAD I adjust the driver positioning/offsets until my synthesized response looks like the measured response before working on the filters. Usually, this comes in pretty close to just using the VC offset from the front plane, so if I'm in a hurry and working on something with a lower crossover point, I'm comfortable just using the physical calculated offset. Rarely have I gotten into trouble that way.

I use an ACO Pacific mic with 88 kHz sampling, and I generally haven't seen much ambiguity for windowing the impulse response in Fuzzmeasure manually; again, if you use the built in function for creating a minimum phase sample, things seem to work out fine, IME. But then it helps to have clean well behaved drivers, too, I'm sure.

When I'm concerned about evaluating the baffle characteristic BEFORE the effects of driver, I usually use Edge for design studies, with a multitude of microphone positions and a fairly dense calculation grid. Sometimes I do this for sealed/ported boxes, but always for dipole designs. Of course, the best test is to use measurements, and I generally favor taking multiple measurements of each driver on and off axis at several positions through a forward 30 to 60 degree arc, and averaging that data to design the crossover for the flattest power response. That can get you in trouble, though, if the drivers fall off significantly beyond 15 or 20 degrees off axis in a critical band; but then, one probably shouldn't be using them there anyway.

This is all pretty straightforward stuff, nothing innovative or out of the ordinary, I'd say.

Is this the feedback you were looking for?

[ergo]

Yes, thank you.

There are only few DIY project authors who elaborate how they do measurements and how their workflow and reasoning is. The different details people have in this process is very interesting though and can teach a lot.

I used to do only on axis measurements with JustMLS, then near field and merging. This produces ok data for simulation tool but does not necessarily sound good in the end.

Thus now I also start by simulating the baffle diffractions first. Edge is good and JeffB-s new spreadsheets are nice - the Frequency response modeler allows to combine the data-sheet tweeter response and baffle simulation, which is a nice feature to have.

http://audio.claub.net/software/jbagby.html#WBC

It is still very odd that none of the manufacturers are willing to make the measurement data of datasheet curves available as text files, so it would not be such a hassle to simulate the performance of driver for a given project.

Though I guess ideal would be to have a LspCad optimizer be able to optimize the driver position against 30 degree angle left and right or similar.

For crossover what I have been doing lately is to measure tweeter and mid on axis but also 5...90 degrees angles in 5deg steps and form an off axis model. Part of the problem is though that LspCad can use Praxis file, but importing the data to Praxis is pretty time consuming. ARTA on other hand allows creating an off axis model also but unfortunately none of ARTA-s supported formats work for LspCad (I should make a feature request to Ingemar ).

Looking at on axis response and power response based on real off axis data at same time has been very rewarding - this has provided much better sounding crossovers.

I also had a chance to buy a Fuzzmeasure for work related reasons, but I do find it very nice to use and it produces stunning graphs and indeed the multi measurement file saving is great. ARTA on PC has much more features, but for a concrete task of loudspeaker measurements what Fuzzmeasure has is very nice.

[Jed]

I used to do only on axis measurements with JustMLS, then near field and merging. This produces ok data for simulation tool but does not necessarily sound good in the end.

I guess that goes to show that if you have all the tools in the world it doesn't necessarily mean the sum of the parts will sound well together. That is assuming you are taking on and off axis response plots of the system after simulating the imported response curves in LSPcad, with the actual crossovers in place.

I find the procedures outlined in the MLS manual work well for other software packages, like Arta for example. The final system measurements verify that. One thing I learned from Jon-- here at htguide, Linkwitz, et. al, is that if you use drivers in their most pistonic range of operation, more than likely the off axis response will hold up well-- like predicted in LSPcad. Obviously one could go through the trouble of taking all the off axis response curves to prove it, but if you stick to that mantra, things will sound right and have verifiable results through measuring and listening.

That is not even taking into consideration phase characteristics, which wasn't mentioned. The response plots only tell so much about that when working on axis and measuring the system. But, if the phase is done correctly in the crossover simulation and construction-- given the crossover is doing its job to hit the target slopes; again, things hold up well on and off axis (flat power response). Just my 2 cents.

Speaker building is also an art.

[Dennis H]

For crossover what I have been doing lately is to measure tweeter and mid on axis but also 5...90 degrees angles in 5deg steps and form an off axis model. Part of the problem is though that LspCad can use Praxis file, but importing the data to Praxis is pretty time consuming. ARTA on other hand allows creating an off axis model also but unfortunately none of ARTA-s supported formats work for LspCad (I should make a feature request to Ingemar ).

All you need is a text editor to copy/paste an ascii off-axis file from multiple files. See Extended format, p.32 in the LspCAD manual.

[data]
## EXTENDED DATA ## OFF AXIS <X,Y>
[data]
## EXTENDED DATA ## OFF AXIS <X,Y>
[data]
## EXTENDED DATA ## OFF AXIS <X,Y>
[data]

[ergo]

Jed, that is true, but only if the drivers have a predictable behavior. Which they mostly have. But I have also played around with waveguide loaded tweeters (waveguides from Finland) and in that case predicting how they behave is much harder.

DennisH - thank you for that very good tip. I will try it out :T

[sdl2112]

Jon,

If you mentioned it already I missed it but what enclosure size did you (have you) use(d) for the C79 sub-enclosure? I may see one in my future and was wondering with its limited low end what you found optimal.

Also was the limited off axis angle testing of the D3004-6640 on purpose? At a glance people may assume it was tested at the same angles as the other tweeters.

Thanks so much for your testing....we really do appreciate it!

Scott

[JonMarsh]

A true pistonic dome tweeter without phase sheild will generally not do so well at 45 degrees or more, unless it's a vary tiny diameter. Cloth dome tweeters do better usually through some bending modes or developing waveguide cavity effects (like the D3004-662001). In this case it wasn't my intent to obfuscate or obscure, in spite of my signature, but just that I was more interesting in detail at a realistic listening angle.

With regards to the C79 enclosure volume, I didn't think it would be this long before I threw all the details up on a web site. To keep things simple, I did model it in Unibox, shooting for an enclosure size to keep the Q at about 0.5 or a bit less; with a nominal crossover point of 300 Hz but controlled roll off desired down to 100 Hz or so, I ended up with ~3 L, which was similar to the target calculated for an RS100-4.

The midrange enclosure has sidewalls running front to back on the inside that are 4-3/4" tall; the interior space is 4-3/4" tall by 4-1/2" wide, by 6" deep.

This top view of the midrange enclosure should convey the concept.



The front wall is toward the bottom of the drawing- the back wall towards the top. The walls are lined with 1/2" wool felt, and stuffed with long fiber wool. Fs in the box is about 175 Hz. LF zobel is necessary for the midrange to get the right roll off function; otherwise the broad impedance peak will mess up any filter attempt.

[mgrabow]

Some measurements...

Per request, the individual drivers are measured as well as the summed total, on the midrange driver axis. Gating window width is 60 msec, so room effects are visible, of course. The cabinets haven't been cranked up on the points fully, and cables are coming through the port, so LF output is a bit restricted- though it didn't really sound that way. Ports don't have the flare extension yet, but tuning frequency is ~32 Hz.



LF Measurement



Midrange Measurement




HF Measurement



All drivers summed. Note that midwoofers and tweeter are at the same level at the center frequency of 900 Hz, at ~ -18 dB. The midrange tracking starts falling off at ~180 Hz on the bottom end, but holds up OK to 8 kHz on the top end. I think I can live with that. :W

This is a newbee question, but how are you measuring the individual drivers on a completed project? Are you tapping into each circuit on the crossover?

[JonMarsh]

Yes, just driving one crossover input at a time- it's a good idea to do so, to see if the target transfer function for each driver + crossover filter set is being realized in practice. A step often omitted, I think.... :W

These were relatively long gated windows, so they show the effect of room acoustics and position on the response curves. It's always possible to "pretty up" things, but more instructive to see what's really happening.

I didn't have a chance to get back to these this weekend, as originally hoped, instead finishing up most of the work on cherry cabinets for the Modula MT project, and getting about half way through an SACD player modification (Pioneer DV-79AVi). But everything is gathered together and ready, probably weekend after next, as finishing the first pair of Modula MT MkII is top priority for next weekend. They're deliverables!

[---k---]

This is a newbee question, but how are you measuring the individual drivers on a completed project? Are you tapping into each circuit on the crossover?

This is offtopic, but I'm curious about your signature. The link in your sig is to a company that designs custom speakers and crossovers. Doesn't add up to "newbee" questions. What's the deal?

[chrismercurio]

"mgrabow"

Is awfully close to a handle from the old Madisound board days as well. Like 10 years ago old...care to comment? I think that guy was a student at UCLA at the time.

Chris

[JonMarsh]

Time to Be all you can Be...

Getting back to this a lot later than I'd hoped this weekend, but at least I should have things ready for some real testing and tweaking another evening later this week- need to go out and get some banana post pairs for plugging things in for crossover testing.




'scuse the cell phone pic- running out of time for nicer shots.

[savage25xtreme]

stockin up on cutting boards I see...

Nice Ardent too :B

Thanks for all that you do, very interested in your new designs.

[JonMarsh]

Ooops! Not supposed to see that secret stash of baffle material, culled from all the Target stores within a 25 mile radius.... the hot tip is the True Bamboo 3205 for the larger cabinets, but for tweeter baffles and braces there are some nice smaller ones.





I also bought a couple of 1 X 12" 8 ft boards at my Pleasant Hill Rockler last Friday. Better for big projects, but I figured to try some of the cutting boards for little items. They're competitively priced in most cases with the raw lumber. :W Seriously, it's to try them out as alternative in case others want to try that and they have a Target nearby, but not a wood shop stocking LBL!

[BOBinGA]

I noticed that the orange box store near me had 5/4" thick stair treads in LBL. They look like they are 11 1/2" by 36" but the round over on the front of the tread looks like it's 1 1/2" and a different material (about the same as the ends on Jon's cutting board). You'd probably have to cut that off leaving about 10" X 36" X 5/4" for just $20.

-Bob

sorry - no pictures.

[benchtester]

Ooops! Not supposed to see that secret stash of baffle material, culled from all the Target stores within a 25 mile radius.... the hot tip is the True Bamboo 3205 for the larger cabinets, but for tweeter baffles and braces there are some nice smaller ones.

John, did you hit the Target across from Rockler in Pleasant Hill?

(I live in Oakland and work in Concord. I am guessing you didn't make it out to the new Target in Albany.)

[numberoneoppa]

The Publix supermarkets by me all sell these and there's not a time I see them without wanting to make speaker baffles out of them!

[JonMarsh]

John, did you hit the Target across from Rockler in Pleasant Hill?

(I live in Oakland and work in Concord. I am guessing you didn't make it out to the new Target in Albany.)

Yeah, that's the one. I didn't make the Target in Dublin, yet, though, so I may check that this weekend- but I think I'm set for now. :W Smaller boards are perfect for tweeter mount baffles behind waveguides. And if you're doing PE cab like constructions, with a step recess back to the front panel, then some of the stores, including Safeways, have 5/8" thick LBL cutting boards about 12" by 16". I just love the way a high grade drywall screw will lock down hard using a 7/64" pilot hole, even if you put it in and take it out several times- with that treatment, MDF just turns to mush. Same thing putting in new tweeter mount screws for the Ardents with the Be tweeters with a total new hole pattern.

[Jed]

How are those Be tweeters sounding so far? I've been thinking about pairing them up with my C173-T6-90s I have on hand, instead of my 6600s.

[SoundOfNothing]

Why did you trade out the 6600?

[ThomasW]

Why did you trade out the 6600?

His response when I asked this was he didn't like the sound of the 6600

[JonMarsh]

My measurements, other measurements, and my auditioning show an upper end peak that I shouldn't hear, but which I do seem to in auditioning-



I believe (possibly erroneously, but what the hey) that it is due to the shallow waveguide design built into the front panel of the D3004/66200 series. I believe this front panel design is part of what gives the 662000 the superior off axis response at 30-45 degrees, but I think it also results in the elevated response in general in this area. I shouldn't be able to hear it, I suppose, but I do compared with the top end on some other tweeters that I find more neutral, like the D2608/9130.

Now, the Be 6640 version has a rather different front panel design, more of a broad shallow waveguide, actually, and not the bell like mouth. It's behavior is rather different.



So I've put it in one speaker, and will be re-measuring and tweaking the crossovers for both- even ordered some new inductors today. This will be a more relaxed and deliberate evaluation than the frantic preparations trying to get ready to drive for RMAF in Denver- I still have a deadline, but now it's late April, and most of the main work is done.

My secret dream of dreams is that the Be drive may give 75-80% of the performance sonically of the Accuton diamond drivers, at 1/4 the cost. The breakup resonance is well controlled, so I'm hoping for a combination of good detail without audible edge in the audio band. That may be naive, but there's only one way to find out. It is rare to find a tweeter as well behaved out to 40 kHz as this one.

[JonMarsh]

How are those Be tweeters sounding so far? I've been thinking about pairing them up with my C173-T6-90s I have on hand, instead of my 6600s.

I should have some totally subjective responses about that, plus some more measurements, before long. unfortunately I have to leave on business travel on Sunday for a week, which means Saturday will be mostly getting ready! Got a few more parts on order, too.

Once I have an opinion and some results, I'll certainly post on that...

[JonP]

Ooops! Not supposed to see that secret stash of baffle material, culled from all the Target stores within a 25 mile radius.... the hot tip is the True Bamboo 3205 for the larger cabinets, but for tweeter baffles and braces there are some nice smaller ones.

That cracked me up when you first posted these... I remember seeing them in a Bed, Bath & Beyond store Xmas before last, (even bought a few for a gift) thinking how nice they would look as a front baffle... not to mention the physical properties!

[JonMarsh]

Yeah, it's too bad you can't actually see any of the LBL in the Ardent's - it's more stealth mode, but when you're doing the driver mounting, it's quite obvious!

[---k---]

Can you post a picture of the end grain of your LBL. (Cameraphone is ok. ) Does it have the same laminations like plywood?

[Face]

Can you post a picture of the end grain of your LBL. (Cameraphone is ok. ) Does it have the same laminations like plywood?

Check page 4.

[JonMarsh]

Thanks, Mike.

I'll repeat a few here..










Tonight I'm listening to Synchronicity from a 24/176.4 source... having a real "80's" moment in bliss!