"... I am interested in knowing the material that you made these out of... I've read you mention doing patents, so if "mum's the word," I can certainly respect that..."

No problem... If ever I were to make horns for sale to others, I would definitely not make them the way I've made these or my other horns. The processes used here are fine for making one set, or a functioning prototype. Doing it this way as a commercial venture would require that one use 3rd world labor, and even then, I would still use other processes.

The product used for the 40Hz horn is made in Germany; it is marketed in France under the name "Plasticrete". There is surprisingly little information out there on this stuff. I've done internet research for the equivalent in the US, but came up with zero. It was once used in, among other places, the auto industry, to make quick molds of clay prototype models. There are people in Detroit who must know where to get it.

It consists of a liquid used to laminate fibers. 

The fibers are soaked in an acrylic liquid (looks sort of like thinned out wood glue), mixed with an acrylic powder (looks like plaster). The ratio is 1 part liquid to 2 parts powder (a drill with a mixing attachment is about the only way to get it properly mixed). The resulting liquid is of a similar viscosity and appearance to the batter used to make crepes over here. The soaked fibers are then placed on the forming tool and left for 3 hours, after which point the lamination is fully cured; hard but not brittle.

I would guess that about half of Las Vegas is made of this stuff, so there must be an equivalent in the US. Over here it is expensive. One mid-bass horn costs me 2000€ in materials (just the bare horn, without driver, chassis, rear chamber, etc).

Above : On the shelves are most of the materials that go into one 40Hz horn. On the top shelf is a roll of very thick chopped strand fiberglass mat, which was developed specifically for this process (one horn takes more than just this one 60m roll)... When rolled up, the fibers are compressed, when unrolled they expand and soak up a LOT of the liquid. The resulting lamination is extremely heavy. One advantage of the product is an absence of shrinkage.

Some may be wondering how I know that one horn weighs around 900 lbs... I know this because I pay for the materials by weight, and I waste almost nothing. Yes that shelving unit is overloaded; the wheels are flat-spotted and will not roll. The whole thing just started swaying why I tried.

To the left of the shelf is a large sewer pipe that will serve to make the adjustable rear chambers (see upper-bass horn a couple pages back).

"... Is there something I should know before I cast my upperbass horns?..."

I assume you mean with regard to matarials (?). From what material will you make them?

"...Aesthetics wise, it looks like you were the designer of the Ariel Atom or Deronda or Caparo T1..."

Well... It would be "off-thread" to go into that; I already feel guilt for having posted photos of my cats!

jd*

"... Is there something I should know before I cast my upperbass horns?..."

I assume you mean with regard to matarials (?). From what material will you make them?

Thanks for replying...I'll email you as not to clutter the thread.

jessie.dazzle wrote:

1) Set horns to fire all in same direction (will require some modification to the house) 2) Move to a new house

jessie.dazzle wrote:

So it sounds like you're considering a move...

Yep, I am contemplating this now…

jessie.dazzle wrote:

Criteria : 1) Main room minimum 80m2 with correct length-to-width ratio 2) No mid-room obstructions (no poles, columns, or other supports) 3) Absence of street noise 3) Ground floor That's all I dared ask for.

Yes, I have in way similar criteria. 1 sq meter = 10.8 sq feet, so you are talking about approximately 900-1000 sq feet.  Of a single room. That is pretty much the dimension that I am looking for. A minor thing that the rooms (lofts) of this size frequently comes in Boston with 43-50 foot ceilings.  This might be a bitch as it is extremely difficult to make such rooms to work well. You need a lot of power and anal or of exertion to feel such a volume with bass and we are vey beyond the SET capacity to do this. I would rather prefer to have moderate 15 foot ceilings.

jessie.dazzle wrote:

I spent 4 or 5 months trying to find such a place, but in Paris, large spaces are often divided up into small spaces in the interest of maximizing financial gain.

Yes, the same is in Boston but I am considering buying not renting so I perfectly intend to tear down the walls… I hate the compartmentalized rooms and dummy corridors as well.
 

jessie.dazzle wrote:

I can position the large horns (which are in fact 40Hz horns) only if willing to accept toeing them in way more than I'd like.

Well, I was conserving to leave a part of the 40Hz horn outside of the walls… anyhow, the subject of real-estate and the bass horn is kind of funny and I think it very well might deserve own dedicated thread.

jessie.dazzle wrote:

I look at this audio thing as something that takes time, and I'm OK with that as long as I don't go wasting any of it. It has taken time, but I feel I've moved relatively efficiently; in any case, this is not a passing interest, and as such, its impossible to over-invest. I do however need to get the project done while there's still time left in life to sit down and properly use it!

Well, you do not need to tell me about it. Anyhow, what I see is that my audio demands for real-estate are WAY more ugly them my out of audio demands for home. The last thing would be looking proportion with reverberation time tester and specter analyzer.  Unfortunately with my consulting occupation I need to be in specific area…. That adds insult to injury….

jessie.dazzle wrote:

Also, I'm convinced that a too-big space is horrible for audio as well as being non-conducive to good mental concentration (some of the best ideas are born on the toilet!)

The subject of playback in very large rooms is a separate subject and to get a proper sound in there it requires very different technique then we are familiar in high-end audio. I tend to agree that in I do not like very big rooms but I never have seen a right attempts to properly sound re-enforce a very large closed listening space.
 

jessie.dazzle wrote:

Those Boston lofts may require lowering the ceiling/adding a second level. Quite easy to do if you keep with an "industrial" theme.

Actually it not a bad idea at all….. I never thought about it, I probably shall…

jessie.dazzle wrote:

I have almost no "normal living requirements"... Give me a non-preformatted space and somewhere to fire up the barbeque and I'll be just fine. Ideally, ….

I do have "normal living requirements" but they are very integrated with my audio habits.  I like when my audio is sitting in the middle of room where I live, I like to take my t-short from washer machine and hang it to dry on my horn overnight, I like when my Cat warms up her ass atop on my amplifiers, I like when women are hissing when I pay more attention for cleaning of my records then to compliment their make up or their hair color change, I in a way like when women get very angry because I remember Rachmaninoff birthday but “forget” my anniversary with them, I like do not go somewhere when I would like to hear what I would like to hear…. Well, lately those anniversary become shorter and shorter, I wonder why…  :-)

jessie.dazzle wrote:

If you've tried both, and decided to keep the 16R versions, you've answered a question I've had for quite a while; I too use the 16R version, but have always wanted to try a pair of 8Ms with 8 Ohm coils (should have ordered them back when Fane were still in business!), just for the sake of comparison when used in a 115Hz horn.

Well, you need to understand that my decisions to go for 16R Fane in 2000 were mostly argon decibels. Since at that time I was driving everything from the same amps I was concern that my upperbass horn would have the similar output with my MF horn. The Fane Studio 8 was born as a replacement of the default driver in the Avantgarde upperbass horn. I got the 8R initially and it was a few db lauder then my MF channels (I use many-many MF driver at that time for MF, including the AG own MF driver). So to EQ the things I do not use voltage dropping in crossover but I drove the different channels from different taps of my ML2. Then I went for 16R version Fane. When later on I when to DSET then the impedance of the drivers lost any significant as it always might be tuned by transformer ration. 

jessie.dazzle wrote:

Sort of on the same subject: I edited the last post I left back in the Living Voice thread; if you've not already done so, it would be interesting if you could comment on my assumption that Vitavox specified a lower R version of their 15" bass drivers in anticipation of the additional load (seen by an amplifier) once the driver is mated to a horn. It seems inevitable that additional physical load would translate into additional R as seen by the amp. Never mind that its likely no commercialized implementation of this driver loaded it to such an extent as to require the lower resistance winding.

Might be, it is hard to speculate. To do it I think it needs to be known how Vitavox intend to drive those speakers and this is the information that I do not have. I have seen a few SS Vitavox amps but never tube amps. I do not know if Vitavox was in tube amps business and I have no idea what amplification they uses in 50s and 60s for sound re-enforcement.  Those sound re-enforcement requires a lot of power – most likely they uses SS amps. I know Pink Floyd used S2 drivers and it was all SS amplification I guess. Still, I feel that in our home utilization we all those drivers to much, much, much more sophisticated degree that they even meant to be used. So, I recognize what they did back then and what their objective were as very much raw material and I do not take their initial intentions too serious.

Romy wrote :
"...I do not edit the posts of others..."

I think you misunderstood my post (my fault; I was not very clear)... I meant to say that I had edited my own post, and was asking for your comment in the event you had not already made one while I was writing the new post here in this thread.

Thanks for answering.

jd*

Btw, I usually have to edit my posts a few times to get colors and font variations to "stick".

Jessie, your post catches me thinking about multi-channel driver matching, as well.  I am not familiar with the Fanes, but I wonder if simply throwing more power at them would make them nothing more than louder, so they would then "match" the rest of the system, irrespective of their "native efficiency".  I guess it's a matter of how much difference we're talking, here, but I've noticed over the years that drivers with differing efficiencies typically sound different, in terms of character, if nothing else.  Let's use LF as an obvious example.  One way or another, LF usually requires more power to "match up" in terms of SPL.  And I think that, if we are honest, where we actually find LF, then "servo bass" winds up more or less "attached" to the rest of the spectrum rather than a "natural" continuation.  Conversly, the "best LF" in terms of character generally seems to be the bass that best matches up with the rest of the sytem.  Don't get me wrong; I have heard some truly astounding "bass" coming from "pro" installations burning crazy amounts of power. At the same time, this has never been anything I'd want in my home.

Sorry to put this mostly in terms of LF.  LF is just an extreme - and obvious -  example of what I'm talking about.  The question is actually about level matching and final balancing in a multi-channel system.  It's hard to argue with DSET, for any number of reasons.  But I wonder how far the idea will stretch to cover channel-to-channel efficiency "mis-matches".

My own mental "modeling" these days - spurred by JLH's posts on the "tapped horns" - is tending to use multiple drivers for each frequency range of each channel.  This seems - potentially - to offer the multiple "benefits" of "oops loading" and added efficiency.

Anyway, lots of self-reflective words to ask generally about efficiency versus character in multi-driver HE speakers.

Best regards,
Paul S

jessie.dazzle wrote:

As for balancing the amplitude between channels by driving them from different taps: I drive the upper bass horns form the 16 Ohm taps, and everything else from the 8 Ohm taps. An 8 Ohm versoin of the upper-bass drivers would allow driving everything from one pair of taps, which would be ideal. I did try using the 4 Ohm taps to drive the S2s; they did not respond well.

If you drop everything to 4R tap then your upperbass horns from 16R tap will have extra 3dB. I did not problem driving S2 from 4R tap – in fact this was the only operation mode I like with ML2. You need plastic suspended diaphragm to do it. The 16R tap… It heavily loads the out tube and I do not like it. It might make bass inappropriately bloomy and muddy.

What you report is sagest that you have very room. Your upperbass with 16R driver in 115Hz Tratrix and S2 with plastic suspension at 400Hz Tratrix has the very same sensitivity – 109dB from 1W.  You run upperbass loaded twice harder it made you have to have 3dB more at upperbass. Apparently your room is large enough and you listening and radiating locations are not “active” enough in the room that you are losing some DBs. Yes, what you finish you midbass horn you will be able to run it along with upperbass and it would help. Still, I would make the upperbass to work properly. The upperbass horn in your configuration is VERY important for imaging of the whole system – it grounds the whole system imaging-wise. Make an experiment: play a piano concerto and set one upperbass 2dB different then another upperbass, with other channels equal. You will see that the whole presentation will sound VERY strange…

What I would do if I were you is to take any cheap amp for test and to run the upperbass from. You will see how your playback sounds when the upperbass is sufficient from your room. Then you will be able to make a conclusion if and how much you need to boost your upperbass.

ayebee wrote:

I’m probably suggesting the obvious, but have you tried adjusting the crossover component values on the fundamentals and MF-channels? On the fundamentals-channel, increasing the inductor-value, and decreasing the cap, so that the slopes cross on the same frequency, but in a lower amplitude, could be one way to decrease the sensitivity without resorting to resistive attenuators. The same could *perhaps* be applied on the MF-channel as well. When I changed the driver in my upper-bass horn, I could increase the cap on my JBL 2420 MF-driver from 3 (if I remember correctly) to 3.3 uF to match the increased sensitivity. This change actually affected sensitivity of the MF-channel more than it did affect tonality. Of course, this is just another way to burn sensitivity, so that particular headache is still not cured. Could you perhaps post a schematic of your current crossover?

Anders, yes and no. You need to be careful playing those games. First of all adjusting the sensitive via crossover works only what the driver sit on transition slope. It means that driver does not operate in a horizontal section of response.  Let take foe instance your JBL 2420. It you use it from let say 7kHz and up with first order then you might to a degree adjust the sensitivity of the channel by moving it higher or lower on the slop. However, if you have your JBL 2420 sitting at 1000Hz or 500Hz then you have no such option as you need your driver to demonstrate linear sensitivity from 500hz to 12KHz.

The adjustment sensitivity by crossover would work on tweeter or on the bass channels if they do not work very wide. It would work technically very well on the Fundamentals Channel if it has a very narrow bandwidth, however, I would not advise to use the crossovering method for Fundamentals Channel. You see, the Fundamentals Channel sets the scale of the MF weigh. It is hard to explain you need to play with it - when you add and reduce the Fundamentals Channel’s output then you moderate the body size the instruments resonators, you can set their perceptual speed and their “seriousness”, you can moderate the level of musical legato of enter presentation and you can tight the upper channels with bass channels to a very high level of “accuracy”. I use “accuracy” in quotes as it is not the “accuracy” per say but rather your perception of “how it shall be”. There is a kink in it though. When you are setting up your Fundamentals Channel via non-inductive volume controls then you change only the Channel’s output. However, if you do not use volume controls but move the channel up and down on the transition slope via crossover then with each change of filter you introduce new phase characteristics and you need to do time re-alignment at each new volume level. The bitch is that when you re-align time then you get new amplitude. You then kill another .5dB of amplitude and then you need to re-align time…It might be a bit pain in ass to do.