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Posted by Paul S on
06-12-2023
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The Loudspeaker (Troels Gravesen project); a report started "too soon" because they've taken sooo long to build, and they fired right up (first try), and they already do Music!
For some time (at least a decade) I thought about
building a very large center speaker, in order to add power and Musical presence
to my stereo system. I played with many vintage drivers, trying to improve the
sound and increase the amount and range of Musical sounds I got from them. Fair
to say, I learned a lot, including sobering up with regards to my own
manufacturing capabilities. As it turns out, I just don’t have the chops to
make my own drivers. During this time I listened to and kept track of many stock
speakers and drivers that interested me, including re-built and classic-type direct,
horn, and hybrid speakers. I ran across Troels Gravesen’s website a couple of years
ago, and I liked the way he went about things and what he said about vintage
drivers and open baffle speakers that I already knew something about. When
Troels came up with The Loudspeaker, I was hypnotized, and I saved up and
bought the Jantzen kit (which includes full specs), then I back-ordered the
drivers from US-based pro sound distributors. I used Visaton horn UHF drivers. My hopes/expectations were fueled
by “classic” JBL speakers I have heard over many years. Generally speaking, I
was hoping to wind up with speakers that were very immediate and lifelike
without being too shout-y or pushy. Due to the pandemic and personal health
issues, it’s taken me a long time to finish this complex and difficult project. Anyone interested in what Troels has to say about it can go here: http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm
Troels’ original The Loudspeaker is either based on or
it’s coincidentally very similar to the fairly short-lived JBL 4345 studio playback
monitor, a Greg Timbers design/model I’d heard about but never actually heard. For
better or for worse, Troels’ version uses selected and mated modern/contemporary
“pro” divers rather than re-built or new JBL “tribute” drivers, along with Troels’
proprietary crossovers and his own cabinet design, which is very similar to but
not the same as the JBL 4345.
Please note: IMO, The Loudspeaker is not a good first (or
second…) DIY project. It’s just too big, heavy (over 200#/ea.) and complicated
for a rooky to handle. This was a very difficult project for me despite I am a
Master Carpenter with over 50 years of experience and lots of tools. Basically, these cabinets are a job for a fully-equipped (and properly staffed) cabinet
shop with full scale panel saws, etc. In fact, CNC would be nice! My approach
was to “circumvent” the fixed equipment with very basic “work-arounds”,
including dead flat cutting tables on the garage floor, a special blade for my
Skilsaw, and several straight edges. I can’t in good conscience “recommend” any
of my work-arounds; there’s just too much margin for error, especially given
the cost of the Baltic Birch plywood, which is very “unforgiving” and difficult
to process under the best conditions. Further, glue-up of sub and main
assemblies also requires flat tables, and 3-D controls. There are lots of
pieces, and assembly is very complicated and nearly impossible without a lot of
pre-engineering and pre-fitting, and, preferably, another pair of experienced hands,
not to mention loads of clamps and well-thought-out control measures to get and
keep everything in line for clamping before the glue sets up. Regarding construction details, I will tell more on Troels’ Builder Response board only.
Here at GSC I’ll try to stick to conceptual and construction basics and focus
on the sound. I do want to want to mention that I spent a lot of extra time messing with
glues and sound deadening/dampening ideas as I went along. Also, I bi-wired
(and internally wired) my Loudspeakers with 12 gauge Speltz Anti-Cable speaker
wire. One pair of speaker wires goes from the amp to the woofer X/O, and the
second pair of wires goes from the amp to the X/Os for the rest of the drivers.
I should also say that my X/Os are all passive, at speaker level. My amps are
Marantz MA9-S2 monoblocks that are literally made for bi-wiring, and these amps
put out a lot of power, including a whole lot of current. I have already posted
plenty about these amps on this board, and they are an integral part of my speakers in my
system.
Per Troels, The Loudspeaker is a 95 dB efficient, 4-way
design that uses an 18” treated paper woofer in a big reflex cabinet from about
25 Hz up to ~160 Hz; a 10” paper cone midrange unit in a sealed box up to
~1,300 Hz; a compression driver and a short horn for upper-mids and treble to
~9k Hz; and I use a compression horn for UHF above 9k Hz, for anyone who can hear
it. Again, look at Troels’ site if you
want full specs. Please understand that I am not offering any specs as “proof”
of anything, in any case. I will repeat,
because I like this quote, what the original designer of the JBL 4350, Greg
Timbers, said of that speaker, that “It does not know it is not supposed to
sound as good as it does.” When it comes to designing a loudspeaker, I agree
with Troels that any loudspeaker is a pile of compromises, so it’s basically a
matter of Pick Your Poison.
Like I said, too soon to say much. So far, I've only listened to 3 LPs: Kind of Blue; Sketches of Spain; Solti/Chicago Symphony Orchestra, Bruckner 7. I actually built them to try to further explore Bruckner and other "difficult" Music, and indeed, new Musical doors are already opening.
Paul S
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Posted by Romy the Cat on
06-13-2023
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Paul, congratulations on your
finished project. I do not have a lot of experience with central channel, I wonder
how you route signal to it in context of stereo recordings. If you use DSP then
I presume that it is more deterministic to the final result than the quality of
your central channel speaker. What I
find interesting in your post is the following: “in order to add power and
Musical presence to my stereo system…”
What do you mean? Why do you feel that your center channel helps you to
add the “Musical presence”? Are you sure that it is “Musical presence” and not something
else?
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Posted by Paul S on
06-13-2023
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OK, Romy, maybe more like, the presence of Music. I felt like I was getting good sound, but I wanted more of it, with "an expanding sense of it", including better "center fill". We have talked here about the technical/electrical problems inherent in re-allocating parts of left to right and center, and vice-versa, and I just could not convince myself to continue the center channel, not to mention the extra amp (which I actually kept on hand for several years...). I got resistant to "solving" the algorithm/allocation thing, and even James Bongiorno himself did not win me over, in the end. What I went for instead, and what it appears that I do have now, is just lots more power that "gets out into the room", to charge the room. The horn I have now is very short and "fast", more like a wave guide, and the sound does not attach to the speakers in my current set-up. I will try to do some pictures. If this does not work out, it won't be because I did not get what I wanted; it seems like I did get that, and at this point I look forward to continuing with it.
I checked again, and I first contacted Troels Gravesen about this project 4 years ago, and I started seriously rounding up parts 3 years ago!
Best regards,
Paul S
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Posted by Romy the Cat on
06-14-2023
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Paul, what I am saying has nothing
to do with your Troels project but rather a psychological exercise to understand
what truly is going on. Also, I very much not knocking at your door with my
mental approach to audio objective am trying to demonstrate that everything is
not so simple.
So, you are injecting int
the room one more acoustic system that for sure “increase the density of Music”
in your room. How can we methodologically differentiate from the changes you
experience after you put your central channel in play and the changes you would
experience if you increased the radiating surface of your right and left
channel? It is not clear what kind signal you use to drive your central channel
and not clear how your right and left channels are installed in the context of
your listening room. So, from perspective of general audio analysis we still do
not know if the improvements you might have related to the functionality of the
“central channel” or related to the functionality of “another channel”. Here is
a little methodological tip that I use myself to understand what is going on. When
you make acoustic change like this, try to take your focus from what became
better towards to observing what become worse. For whatever reason when this
think about what become worse we are dealing with known N it multiple time help
me to debug problem much more accurate.
Anyhow, if I were in your
shoes I would experiment to drive the center channel from different type of
signals, probably a good digital signal processor would help you with
experiments To get out of main signal sum, delta, different phase shifts, and all
of it might be very much frequency dependent. The digital companies did a tone
of research in this direction. While you experiment with this do pay attention
not only to what became but what became worse. Interestingly, I do not
recommend to find error configuration when amount of worse is minimal and to
use it. However, knowing in which configuration the damage from central channel
is minimal will give to you a reference point upon which you can keep your
mental aim.
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Posted by Paul S on
06-14-2023
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Romy, are you thinking I am running a center channel now? I am not. I am just running the new stereo speakers, right and left. I had already decided that I wasn't going for the center channel before I went this way, for all the reasons I cited. I made an announcement about it and sold my 3rd amp, maybe 3 years ago. The only way in which my current stereo set-up "derives" from thoughts about a center channel is the idea of putting substantially more energy into the room, especially in terms of "center fill", and I have done a version of this with more powerful stereo.
Best regards,
Paul S
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Posted by N-set on
06-17-2023
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Paul, congratulations! But which of Troels' projects have you completed? The webpage shows them all.
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Posted by Paul S on
06-17-2023
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Jarek, it's the biggest thing he's done, as far as I know, dubbed... "The Loudspeaker". Hence, the title for the thread... He went on to do successively smaller versions, the TLII and the TLIII.
http://www.troelsgravesen.dk/The-Loudspeaker.htm
Best regards,
Paul S
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Posted by Paul S on
06-28-2023
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Weird, I realize, but this speaker project included a
mental exercise about “proper” playback for Bruckner 7”, how to facilitate hearing
and figuring out what is going on with that Music. As ever, I turned different
speaker and amp ideas around in my head like a Rubik’s Cube, trying to mentally
line up a design with the sonic goals until they “clicked”. I have heard very
little Bruckner played live, but brushes with Bruckner’s music, live or
recorded, always piqued my interest, even as it confused me. My previous
speakers are good enough that I have known for some time that Bruckner uses LF and
dynamics “differently”, but I haven’t clearly heard, felt, or understood what
he is doing before now. Very generally, I felt like I needed “more” of what I
had, and it would be a plus if only the 2 speakers had to change. With these
speakers (and the same MA-9S2 amps) I can finally hear and feel the incredibly
rich LF sonorities that Bruckner creates. I also hear differently/better and
understand better the slow to mid-tempo “crescendos” that eluded me before, now
that the rising and falling is better articulated, resulting in certain rich
textures that derive from amazing, subtle timbrel and dynamic instrumental
contrasts, both assonant and dissonant, at times spread out over surprisingly
long intervals, and at times very loud. I also enjoy the way Bruckner uses
large ensembles in every register to weave tapestries of sound, including
texture. The feeling I get is that Bruckner seems to be in grateful awe of Creation,
and his Music makes me feel that way, too. Perhaps, once one hears and
understands Bruckner this way, it is possible to hear and feel it from a car radio
or a boom box. Anyway, I am just, finally, starting to get it, and it looks
like I took a wild shot at this, and it’s working! In truth, when I read about
these speakers, I equated them with big JBL monitors I’ve heard, and they
“matched up” pretty well with my developing mental picture, which included most
of my existing set-up, and I pulled the trigger. I referred several times to
this project as my “latest folly”, because I was not 100% positive how this
big, difficult, expensive project would work out. Heightening the tension, I
built the whole project before I listened, over 3 years, and I basically feel
like I lucked out. Others can decide if my 60 years interest in audio,
including a fair amount of DIY, and tons of “mental cataloging”, gave me the
background to steer myself where I needed to go to get what I wanted. I’ve made
plenty of audio mistakes. I’m glad this was not one of them. I should also say
that I remain a musical omnivore, and if I’ve lost anything by adopting these
speakers, in gaining Bruckner, I have not noticed it yet. I feel like it was
Troel’s design; I just curated, and I was lucky. It would be too funny if these
speakers only did well with B7, but not other Bruckner!
>Sorry about image size! This is the first time I posted a picture here! It took me several tries. >
Paul S>>
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Posted by Romy the Cat on
06-29-2023
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It is a very interesting subject, Paul. If we presume that an acoustic system has an objective the most “interestingly”
reproduce Bruckner, then what the acoustic system he should do? Pay attention I
did not say more “accurate” or more “faithfully” as that is a whole different subject
and the one that I do not particularly subscribe to. I do not wan to hijack you
thread as I can write 1000000 wor0s about it but I think thinking about it for
an audio person is very healthy.
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Posted by Paul S on
06-29-2023
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Romy, I actually feel a little sheepish that my process did not include a multi-media map for others to follow, if they choose to, although Troels already did a great job of exactly that. I did post construction pictures and explanations on Troels Gravesen's builder response board:
http://www.troelsgravesen.dk/The-Loudspeaker-1_Paul_US.htm
This hyperlink is the place to look for construction details pics, although I will be happy to discuss here both the rote project and the Bruckner/Music connection.
Again, Romy, I did not mean to make the picture so large! Feel free to reduce the size of it!
Paul S
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Posted by Paul S on
07-09-2023
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Via Mengelberg’s performance of Ein deutsches Requiem, Philips CD
Perhaps it’s possible for someone to “get” Brahms’ Ein deutsches
Requiem by way of a table radio. Speaking for myself, I only got hints that way,
and it wasn’t until I took special steps with my sound system that I began to
understand this mighty work. Naturally, I had to try this CD with my new The
Loudspeakers! And despite the CD itself was damaged a while back by playing it
in my old Volvo, I was immediately drawn into the piece and I had a better experience
with it than ever before. Make no mistake, the re-recording of the 1940 live performance
is not “audiophile quality” to begin with, and The Loudspeakers are not good
because they “fix” that problem, but they are good because they bring me more
than before from both the Music and the performances, despite the compromised
aspects of the recording. I can’t say there is more color from The Loudspeakers
than from my BassZillas, but there is certainly more coherent LF information.
In fact, there is more coherent information at all frequencies, and the sound
spectrum is better sorted out, overall, as well, I think, generally less tipped
up. Massed violins are better pitched, and more natural for that, and they are clearer
vs. recording artifacts; and the same with chorale voices. Basically, I get
More Music from this CD, and this has been the case with several “compromised”
recordings I’ve listened to, so far. I am still working to get my vinyl playback
where it was before I pretty much went off the rails, a couple of years ago,
but even now I get Music that can be better than the sound of the LP itself
would suggest to an audiophile. I am always happy to add program, and so far
The Loudspeakers are helping me to do this.
Paul S
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Posted by Paul S on
08-08-2023
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Like I said in my previous post, I lost my
tonearm/cartridge synergy a while back, and then I realized that I needed to
replace the surrounds on the drivers in my BassZillas, and I shut the system
down for some time, until I got The Loudspeakers up and running. So, I’m glad
to say, it’s been pretty easy to tell what’s going on with the system via The
Loudspeakers, as they break in, and I as blow the cobwebs out of my long-idle electronics.
Today was especially nice, starting with some Coltrane, then on to the Scherzo
and the Finale from Bruckner 7. Great listening to both LPs, and I still feel
expansive enough at this point to say these speakers were “worth it” just for
the Bruckner 7! By the end of that LP I was weeping with joy! This Music is
magnificent! I really look forward to “getting into Bruckner”. I just now found
a few more Bruckner LPs I was afraid I’d just imagined. I guess I’d “set them
aside”, then forgotten about them, because they were not where they were supposed
to be, in my record racks, where I expected to find them (but couldn’t) last
week. I plan to get Wand’s Bruckner 8 that was recorded live in Lubeck. I’ve
only seen this performance on CD, so I guess that’s peripheral to this post. As
for how, specifically, The Loudspeakers have revealed Bruckner to me, it turns
out I got the “more” I wanted. There’s just more Music there now than there was
before, and The Loudspeakers do more Music with less fuss and bother; they make
it seem natural, and “easy” in that sense. I’m still messing with speaker
positioning, pretty much gilding the lily.
Paul S
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Posted by Romy the Cat on
08-09-2023
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Paul, you are lucky person,
I never was able to find Bruckner music on LP that I felt was good quality sonically
and artistically. I own a lot of Brucker LPs but I hardly ever listen them.
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Posted by Paul S on
08-09-2023
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Well, Romy, at this point I am listening more to the
Music than to the performances, if you know what I mean. I already shared the
Solti/CSO 7th LP, an old London ffrr stereo that does not seem to
have the weird curve. So far, that’s the beginning and the end of my good luck
with Bruckner LPs. I hope but do not expect to be so lucky with the other LPs I
just “found again”. After all, there were reasons that I haven’t played them
for years. It remains to be heard whether I can glean significant Music from
these LPs.
Paul S
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Posted by Paul S on
08-13-2023
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Like I’ve said, my aim was to find/build a pair of
speakers that could be driven “full range” by one of my Marantz MA-9S2 amps per
stereo channel, and these speakers would have to give me greater insight into
Bruckner in order to fill the bill. I put “full range” in quotes because, now
that I have stronger, deeper LF I can hear “what it would be like” to have ULF.
And so it goes. Does this mean there is a problem with TL bass? Perhaps the apt
analogy is adding a helicopter deck to one’s luxury yacht. After all…
Meanwhile, it seems like these “95 dB” speakers play
louder at the same volume settings than my “97 dB” Basszillas. Not that this is
the first time in my audio experience I’ve noticed this sort of discrepancy.
One case in point is my Visaton TL 16 H (horn) super tweeters, which definitely
play louder than my Audaphon UHF ribbons, at least they contribute more at
higher volumes. And I think this is part of the phenomenon, that the
lighter-weight, “more efficient” drivers choke up when the going gets tough. I
have to say, the TL drivers have sounded better and better as I’ve played them
more and more, not in the sense of some “ever-present” quality or qualities,
rather they do a better and better job with “soundstage” and rendering dynamic
and tonal differences. If I was happy before, I am becoming fairly content with
these speakers. I suppose it’s in my nature to push my sound system
occasionally, just to do it. A nice 10 - 12” vintage driver powered by a small
SET can produce some intoxicating music. But it does not make Bruckner happen
for me. The Loudspeakers and my amps do make Bruckner happen for me, and the
combination makes Casals or Manitas de Plata sound pretty good, too; in other
words, they seem to “scale” well.
Paul S
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Posted by Paul S on
08-16-2023
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Something worth thinking about as one chases an “ultimate
sound system” is that “accurate” playback will likely reveal sounds of the
recording process along with the musical performance. And The Loudspeakers are
certainly “guilty” of this. From knobs being twiddled, to reverb, mixes, and
artifacts from previous iterations, the playback through The Loudspeakers will
be a close repetition of the signals they are fed, for better or for worse.
Speaking for myself, I would rather do without the sounds of the engineering.
However, these sounds have so far been a consequence of insisting on “faithful
reproduction” of recordings that has otherwise paid off in terms of Music
appreciation. I am certainly open to getting the upside I get via The
Loudspeakers without the baggage, if anyone wants to share how that’s done. But
to date I have not heard “the good without the bad”, as it were, on this score,
although some recordings are better than others, for sure, in any number of
ways. As I have noted, The Loudspeakers
do not emphasize non-musical or a-musical parts of recordings. In fact, they
seem to do a pretty good job of “sorting out” and “setting aside” parts other
than Music. So far, this has been better
than worse, and I continue to work to take advantage and make the most of good
engineering and poor engineering.
Paul S
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Posted by Paul S on
08-23-2023
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A while back I mentioned that I would not want speakers
that could not “do” Gieseking. Well, The Loudspeakers do Gieseking, all right,
including telling me more about his performances of Debussy’s Etudes. I have
long admired and appreciated Gieseking’s wide range of expression over a
relatively narrow dynamic range. Via The Loudspeakers I can now hear and feel
his physical strength, and just how hard he can push the keys down with no
“wind up”, and it is clear now that his overall dynamic range is a good deal wider
than I’d thought. I had also thought that his use of the pedals was very
limited. But now I can hear that I was quite wrong about this, as he uses the
pedals extensively, he is simply deft at this, as he is with the tinkling
chromatics that light up this Music. He also feels less aloof via The
Loudspeakers; I can feel his vulnerability as he performs. This from a brittle
old Angel LP that most audiophiles would pass on, I’m sure, not to mention this
Music sounds like gibberish through most systems, to begin with.
Paul S
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Posted by Paul S on
09-03-2023
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Something about The Loudspeakers that shoppers have
likely noticed is that the original design electrically splits the 18” woofer
from the MF, HF and UHF drivers. And,
just to be clear, there is sound thinking based on lots of experience behind
this design. It takes lots of power to get deep, Musical bass at concert levels
from a loudspeaker, and if there is a work-around here, I have not heard it
yet. To be clear, I am not talking about sound effects or Mobile Sound Club
systems, but I am talking about serious Music via home systems. Troels saw/heard
the wisdom of Hypex for LF, to allow for better sounding amps for the other
drivers. And anyone who goes another direction (as I have done) will want to
think it through carefully (as I have done) before committing funds and effort.
I am still playing with my Loudspeakers, but another thing worth thinking about
is that a woofer that does 200 Hz Musically won’t be doing Musical 18Hz at the
same time. Based on things I read, it looks like plenty of vocal audio people think
“good bass” means prominent bass, just like “good HF” means lots of details and
“air”. I think I will not get on my soapbox but I will answer questions about
this if/as they come up. Meanwhile, 18” woofer notwithstanding. The
Loudspeakers have nothing to do with prominent bass or sound effects but
everything to do with the unaffected revelation of the Music that’s in the
recording, at least this is true of my version. I will say I would not be happy
if I found myself mentally parsing the Music as I listened to it. I am OK with
the compromises embodied in The Loudspeakers (my version, anyway) because they
have a very broad range of Musical expression that allows me full access to my
Music Library.>>
Paul S
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Posted by Paul S on
09-13-2023
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I’m thinking I’ve never mentioned on this board that the
listening room I’ve used for the past 16 years is 21’ X 17 ½’ X 8’. It has three large openings into a very
large house, including a long, wide hallway and successive open rooms. This
means The Loudspeakers have a big job to do in order to charge this room. My
strategy so far has been plenty of amplifier power, and sitting close to the
speakers, which I have well out in the room, over 7’ from the front wall. The
sound I am after at this time is the sound that charges the room and “appears” spread
out behind the front wall, loading into the room from there. There is little to
nothing in the way of standing waves, and I am amazed to get plenty of HF from
my horns with the speakers slightly toed out. Orchestras can be very powerful,
depending on how they are mic’d, and well recorded solos and ensembles sound
and feel like that, according to the production. As far as the drivers go, these
are not high directivity, quite the contrary, so they lose those benefits but
gain in terms of room loading. Between the 18” and the 10” direct drivers and
the M/HF compression driver with its very short, fast horn, these speakers
really do seem to charge the air, itself at all frequencies. I am surprised and
pleased that the Visaton UHF horn also, somehow, gets its contribution into the
mix off axis. I will say, as I have opined before, that there is such a thing
as too big for a listening room, and I feel like I am right at the limits of
what I can use with these speakers and my present amps. While there seems to be
plenty of electrical and mechanical power for more volume, I think I would have
to do something to contain the sound to keep the air charged if this room were
any bigger. I would also say that a smaller room would be fine with these
speakers, and one might then use smaller amps for MF and HF, although I stick
to my previous observations regarding LF and amp power: Even in a smaller room
it takes big drivers and big power to get orchestral LF.>>
Paul S
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Posted by Paul S on
09-23-2023
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Today was a good day in The Loudspeaker Land. I’ve been
using The Loudspeakers to do some targeted listening, with excellent results. I
already mentioned at the start of this thread that I had lost my
cartridge/tonearm synergy a while ago, and today I got it back. From there I used better
Sound to dial up the MOSFETs in my phono stage, also with great results,
including more depth and vertical ambience, and I’ve re-positioned the speakers
closer to the front wall, resulting in greater room charging.. I think (hope) all this will
keep me pie-eyed and not thinking about Reverb Injection for a while.>>
Paul S
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