UPDATE:  Plywood vs. Hardwood



Having spent quite a lot of time with the plywood ZF15M baffles getting the drivers to break-in, which they did, I was able to remove the drivers from those baffles and install them into the new cherry baffles.

I have now spent enough time with the cherry baffles shown above, that I can confirm there is an audible difference in sound between plywood and hardwood. The hardwood has better clarity in the upper midrange and top end with a flatter bass response. My previous worries about perhaps having the F15 too close to the floor and thus accentuating the mid-bass slightly have been alleviated. That part I can't explain. Perhaps it's just that the overall sound is slightly cleaner and I noticed it in these two places...

The plywood was overall slightly softer sounding with more bass weight albeit in a narrow band of frequencies.

Choosing cherry for this pair was motivated by wanting to stick with a single wood and one on the lower end of the price scale. I definitely have my new favorite look over the other two, and I have to say the sound of these is pretty glorious. They have wrecked my acoustic memory of how the bigger ones sound which is rare.  In fact I can't remember ever a time that this has happened, it's one of my strengths! I can remember how things sounded for years. In fact I can listen to how things sounded in my mind during listening sessions which is to say hear both at the same time and compare in real time. And the best part is it doesn't have to be the same song or music. This is one of my most valuable A/B tools I have for design and it's just in my head. Well, listening to these speakers, it's like the whole circuit is gone, so either these sound exactly like the big ones, or they're so close in satisfaction that it probably doesn't matter which one you have, hell they might be better in some ways.  

When I look at all three I realize that the third time is a charm from an artistic perspective. Studying the shape and mass relationships in all three, the last ones finally got it perfect.

So I couldn't be happier with these. Having done some research, these are probably going to be about 1/2 the price of all the open baffle speakers they spank.



Steve

Really nice Steve.  Inspiring for me to see your work.  I also like that  size.

A couple of observations.  

This past weekend I was up at my cottage to shut it down for the winter.  It was pretty cold so I spent some time inside listening to my regular ol' Betsy drivers in baffles with a pair of Augies run by a plate amp.

Lately, the speakers I have been listening to at home are the Crystal 10s with the AE LO15s.  I was struck by how good the regular Betsy drivers were in comparison to what I was hearing with the Crystal 10s.  At around 1/10th the cost, they are really pretty good.  For those of you not in a position to drop that much coin into a set of OB speakers, what Randy offers is a really good value.

Given some of Will's comments here and an email exchange with him, I finally put the Big Betsy's back in my system to compare to the now broken in Crystal 10s.  I was immediately struck by their bigger scale and sense of engagement.  Not the detail of the Crystal 10s nor the exquisite bass of the AEs, but I'd have to say they were more musical overall.

In subsequent listening sessions, I have found it easier to get myself into the "zone" with the Big Betsy's.

To be fair, I do not have the Crystal 10s/LO15s in a proper baffle yet but in this comparison, Big Betsy was my preferred speaker.

I am looking forward to putting the Crystal 10 drivers into their new baffles over the weekend.

I wish I could combine them into one speaker !

Yes, thanks Pal and Archie for your comments on the F15. Also those from Steve as he went along, it seems the limits in extension may or may not be an issue for me, but everyone seems to get so "caught" by the F-15/big baffles, evaluation seems to get quickly forgotten...a big testament to the speaker's qualities for me.

These impressions fit well with what I heard from  the stream...preferring the F-15s sweet textural "magic" and big/fast bass seamlessly integrating with the rest. Watching the stream too, I found it very interesting that the big baffles and new HR-1s caused trance-like listening more than the others.... Maybe just when I tuned in, but the sound that conveyed through my headphone setup did seem extra complex and rich with these two speakers also...engulfing and seductive.

Am I wrong in imagining being able to integrate an appropriate tweeter if I wanted an F-15 baffle to go up more??? I have been tuning away on my updated HR-1s, and that tweeter goes high and is quite fast and clear, but also pretty tunable with caps and resistors making ways of integration relatively easy and flexible. What do you all think of a tweeter with the F-15?

So if I get the Crystal 10s - and say the AE LO-15s - the thing I may try is an active or digital crossover between the 2 - say as high as 450hz to see if that gets the slam and impact of the 15" woofer and you then retain the detail and transparency above that point.  I think that is the passive crossover point Pure Audio Project uses on their Trio15s.  So this violates my desire not to filter the signal going into the Crystal 10s but would be interesting to hear what that sounds like.

Quote:


F15's are a freak of nature.  I can confirm the above statement.  Crystal 10's to be a fair comparison need to be in a cabinet.  In a cabinet, they have nearly an octave lower bass and it does not roll off.  Will shake your entire house.  Still, compared to the F15, they don't have the same hit.

Steve

Make sure you have the "S" in the https: Decware address.

Trying to get slabs large enough can be challenging. What do you think about doing something like a river table? 2 pieces on the sides with the center filled with epoxy resin? Any idea on how it will effect the sound? Cutting and drilling it is an adventure but there are lots of color choices and it can fill quite a gap. Thanks

I've made a couple of pieces with the epoxy resin it's not that difficult to work with, a little messy and lots of sanding. Thought it would be an interesting look.

I can't imagine how a big "stream" of epoxy would sound with hardwood, both responding with the driver resonance-wise differently. Would they be complimentary? If so, it seems proportions of each could effect tone quite a bit, perhaps with fairly narrow parameters for best sound?...No idea here, just some questions.

If I had to guess, I guess that plastic will sound "dead."  Plastic soundboards are not used for instruments.  That said, I'd be curious about baffles made from natural stone and even the man-made "Quartz" stone.

Good idea Adam. Just like the TT tonearm!

New user; spent way too much time today reading this entire thread!  I'm going to have to get with Randy at some point and go listen to his speakers since I'm just a couple hours away in central Ohio.

One thing I didn't see (and maybe it was posted elsewhere on the forum, link?) was what people thought of the Lii Audio full speakers that were at DECFEST?  (Steve's initial impressions shown in reply 759)

appreciate the links!

Got my birch butcher block Big Betsy's done this past Thanksgiving weekend.  They look a lot nicer and, perhaps, sound a little better than the MDF version but its not an overwhelming audio difference.  They might sound a little clearer in the midrange but the bass sounds pretty much the same.  








Dan

Dan: those look really nice. And look as if they sound even better!

Good work!

The butcher block was $229 for the large piece, 74" x 39" x 1.5" (BBCT1502574 - Home Depot) and $109 for the small piece, 50" x 25" x 1.5" (BBCT1502550 - Home Depot).

I wound up facing the bottom side forward because it had more contrast between the glued up pieces that I thought looked better - more interesting.  Finish is linseed oil and then a coat of spar varnish (that was probably older than I am, but was still good).


Dan

This perfect plank stuff is nice to work with. I used it when I was a pattern maker.  https://perfectplank.com/
Not cheap but not outlandish.

Speaking of improvements, I have been enjoying a day of re-arranging in the shop and installing my media shelf.  As a result I had to find a place to put this rug, so I tossed it here.  The sound improvement is 12% if I had to estimate.  It is good enough that I will not be able to remove the rug now that I've heard what it did.  



Yes, a rug on carpet.  It makes sense, because it's creating a better diaphragmatic absorber and probably lowering the absorption frequency an octave or more.  I hear a more refined bass/midbass character and overall more animated image.

In fact this has been one of those evenings where everything is sounding lucid and wet.  I am just so impressed with these speakers!



Steve

Here is some insights into how sound behaves in wood.  The tuning fork demo is pretty excellent.  I started the video just before that part.

https://youtu.be/Em3oOJLTMks?t=63

Steve

I made the link above because I found it fascinating just how much the tension, wood type and design effects resonance in wood -- simply supports the notion that in these baffles different woods and construction techniques can actually sound quite different.

A piano soundboard, is a mechanical amplifier that makes the piano work.  We are not trying to create a mechanical amplifier with the speaker baffle.  In fact if you look at the frame of these pianos that the sound board connects to, it is massive.  Without that, the soundboard would not work, just as a speaker cone will not work without a frame to hold it.

If you were to make a comparison against a piano, the baffle of these speakers would be more like the frame the soundboard is glued to while the driver itself would be more like the soundboard.

I suppose it would be possible to make a hollow baffle frame from 4 x 6 oak curved beams, built like a piano, and put a soundboard in it with a slight twist to tension it and mount the woofer on that, but I fear it would take about the same amount of time to get that to work right as it did to invent the piano and even if successful, why make something 20 times the price just for the sake of complexity?  I can't imagine it sounding that much better, in fact I only imagine after tons of work, it sounding almost as good.

Steve

I still get confused about what the baffle is doing.  But it does amplify the sound, right?  

In the video, the example of bending the wood with the tuning fork showed that stress (tension) raised the volume.  Is the wood then more like a drum skin?

So, not like a panel speaker or like a music box motor that gets amplified when it's put on a table top versus in your hand?  I never tried playing the F15 out of its baffle.

UPDATE

I am still listening to the Cherry pair of ZF15M baffles as pictured in earlier posts.  I haven't had the urge to change them or try any other speaker yet, which is pretty good when you have an entire room full of speakers wanting their turn.  I have been playing them on a variety of amps so far, have successfully used them for at least 4 listening sessions with customers and am still amazed by all of it.  

The efficiency of these speakers takes the power equation largely out of it, making the 25th Anniversary Zen Triode amplifier hit just ever so slightly harder than a TORII Jr, TORII MK4, and ZMA.  I'll just never get used to that.

Anyway, I think over Christmas I'll probably put the large ones (ZF15L) back in and see how much more they bring to the table after many weeks of exclusively listening to these...

So at this point I think it's safe to say the test was a complete success with the possible exception that some people on Facebook think it looks like a toilet seat... now is their mind in the toilet?  

That's fine, it will be some free advertising  

No, I'm saying they could make you shit you pants during a demo.

Well, as an example, I often like to work the 25th Anniversary Zen Triode amp to exploit it's dynamics and weaknesses (which I have not found) so that I can know firmly where it stands in the grand scheme of things and what better music than 24 bit masters of Yello, and Borris Blank and Similar electronic music.  Tonight I spun the following track:

https://open.qobuz.com/track/8842315. (the link is only for the 16 bit version which lacks by comparison)

and about 1/3rd of the way into it, I realized the volume was as loud as I would ever get with the ZMA and the DNA2 speakers, but actually was hitting harder and had better delineation.  All night I have been listening to this kind of music gazing up at the amp waiting for the OA3's to blink, indicating the amp was nearing its power limitations.  They never blinked.  Then this track came on and was probably 6dB louder than the majority of what I'd been listening to all evening, and now I'm certain those ol tubes are going to be blinking their ass off, and NO!  Not even flinching.  It's just too hard to believe.  Really this is the demo for this amp and speaker pairing to show what is possible from 2 watts.  Not a hint of distortion and loud enough to be heard outside the building.

So as I've mentioned many times, the amp and these speakers have set new benchmarks that have exceeded everything we've done to date.  

What's fun, is the high power advocates who enjoy juicing SET owners into the back wall with 120dB SPL's from their giant wall of power and multi-way speakers would if here listening tonight find themselves setting on the couch with a puzzled look on their face and never be the same after they left.

It's true.  These speakers outperform nearly everything on so many levels, not the least of which is speed.

Speed is how fast a loudspeaker can stop.  If you have more than one driver complicating things, then it is how fast a loudspeaker can stop and how close can the two stop together.  These speakers are fast with big balls to back it up, making virtually any kind of music sound and feel like it's real. It's the ultimate B.O.C. audio achievement and would put fear into those who preach about multi-driver design superiority.

These speakers get virtually ALL music right.