Those look tiny
(and very professional)
If you can measure and correct the response (sorta like a Linkwitz Transform), and are planning a steep enough acoustical crossover slope (or a high enough crossover frequency) then a BR is often a better solution as it reduces excursion/distortion.Originally Posted by sebackman
This can all be simulated using winISD pro (beware that the EQ implementation in this software is a proportional Q type, whereas your BSS uses constant Q...)
Hi sebackman,
Nice work indeed.
If You plan to arrange 2-way box, I would suggest You to try with JBL D16R2441 ALUMINUM diaphragm, as it seems to me the best compromise if it is planed to be use up to 20kHz. Even D16R2445 Ti (that has more ringing around 12~14kHz) behaves usable up to 20kHz.
I think 2206 using as mid-bass in the sealed box about 50Lit would be the best solution.
If 3-way network is of interest may be DBX DriveRack PA2 would be acceptable solution (amazon.com 320 U$D).
regards
ivica
Thank you Pos and Ivica,
I guess I will have to build one of each to test. Cross over under the 2206 is planned at 80Hz-ish down to sealed SUB1500's.
For XO I only use BSS nowadays. I like them better than the DBX units. I do have a Driverack PA but a BSS Omnidrive with the newer FW sounds better IMHO.
updates to follow...
kind regards
//RoB
The solution to the problem changes the problem.
-And always remember that all of your equipment was made by the lowest bidder
Nice work Rob.
Here , I posed this question on another thread re the 2206 .
Since it is the inexpensive go to Mid Bass for projects like yours the problem is that it runs out of steam at 80 Hz. Since you are unlikely to need to use the 600w power that is available pehaps an option would be to re surround with a more compliant foam rather that the stiff pleated surround.
Clearly this will change the free air resonance down the way. Prehaps even add a little mass. This is all from the JBL method that we have seen before ( 2234 / 2235 ) You have enough measurement gear to work it out from there.
Since the 2206 is pretty good all the way up to 2K ish you have frequency range in hand Vs the x/o frequency.
You should be able to get it down to 40-50 Hz. Of course power handling will drop but that should not be an issue in your application.
Cheers Mac
Update,
Not much has happened. I have spent most of the summer time enjoying some time off. A few weeks in the US and some time at home.
The "muzak boxes" for the garage (2206/2450SL/VTXF12 horns) are all done as per above. Still too many drivers on the shelfs.... New projects.
Glad my little quest for M2 WG’s back in January has resulted in so many nice and talented people on this forum getting their own sets. It will be interesting comparing notes when some systems are up and running.
Three of the eight M2 WG’s I brought to the Nordics are shipped off to Gothenburg in Sweden and only five remaining here :-) .
Three of remaining five are shipped off to the guy who does the M2 adapter plates for me. He is going to mill away the edges on top and bottom so the WG will be even on all sides. That should make the cabinet structure easier without impairing the sound. I will post pictures when I get them back. He is also doing some additional adjustments, but more of that later.
Since I have some restrictions in size due to all speakers in my HT being wall hanged, to reduce the frontal acreage will be appreciated by others in the family. The M2 WG’s are not very discrete…
The last pair WG’s will probably go into a floor standing pair for 2-channel listening without sub, unless someone else needs them more than me. Probably with a good used pair LE14H-X or 1400PRO if I can find them. Only thing I have is a new pair of 2226 that may work. For the HT it will be 2206 to reduce size and there I do have subs.
Ideas much appreciated. Also hints on where to find a good pair of woofers.
-Probably getting the “treated” WG’s back within a few weeks.
Kind regards
//RoB
The solution to the problem changes the problem.
-And always remember that all of your equipment was made by the lowest bidder
Dear all,
Following some months of minimal action I hope to get some time over for building again.
Since there already is a thread dedicated to M2 clones and that is not what I’m attempting I will keep feeding into this thread.
After finishing the garage speakers as per above, the project has de-railed again and spun into two projects.
The first project will be a pair if stereo speakers for my overnighting apartment as I commute to work. They will be equipped with M2 “MkII” waveguides, 2450SL drivers and LE1400H woofers. No subs. I will try to put them in a pair of SP215-9 cabinets I have laying around. Please see picture with a 1400PRO for an idea. I’m going to use LE1400H’s (now getting new edges) and they are much smaller in diameter so they actually fit in the box whereas the 1400PRO does not. More pictures to follow.
The M2 is exactly as wide as the cabinet and it will be flush mount. I will add in a new baffle that will set the waveguide in level with the cabinet top. There will also be a new baffle for the woofer so that the woofer baffle and the front of the waveguide will be flush. Hopefully I get my LE1400’s with new edges within a few weeks and the fun begins.
I will use a Crown CTS4200 with a build-in BSS Omnidrive to drive them. 4 x 240W I plenty in an apartment .
The sharp eye can see that the “MkII” (have to call it something, right?) designation of the waveguide means that is lower than the original. The original waveguide is 394mm high but mine are now only 352mm to reduce the frontal surface of the cabinet. –Amazing what can be achieved with a CNC machine and some brave decisions.
In the cabinet I will mount them upside down with the JBL badge on top to reduce the distance from the woofer to the driver. Anyone with ideas how to source a JBL badge that can fit except paying $50 for the original M2 badge?
The other set will 3 new fronts to the HT equipped with M2 “Mk II improved” waveguides, 2451Be, 045Ti-1, K2 9800SE horns and 1400PRO’s. The rears will be 2206 with VTX F12 waveguides and probably 2451Ti’s. Or if I can source 2450’s, take of the snout and use them. -Anyone having a set of 2450 with our without diaphragms for sale?
Attached picture is to give an idea of the plan. And also here M2 MkII will be used albeit in “Improved” version with a 045 horn recessed in the waveguide. What do you think of that?
The woofer will be mounted slightly off set to make space for a reflex port.
I think using Be diaphragms may call for a super tweeter, at least from my measurements.
Best regards
//RoB
The solution to the problem changes the problem.
-And always remember that all of your equipment was made by the lowest bidder
Here are some additional pictures of the "Improved" version :-)
I also added a picture to show the difference between 1400PRO and LE1400H in size, the LE basket is much smaller (please note the favorite speaker building tool at the bottom of the picture...)
The 1400PRO is dia 362mm and the LE1400H is 355mm. The width is 343mm for the 1400PRO but only 325mm for the LE1400H.
I can't fit the 15"'s, so I have to make good with the 14"'s and/or 2206.
Best regards
//RoB
The solution to the problem changes the problem.
-And always remember that all of your equipment was made by the lowest bidder
http://www.audioheritage.org/vbullet...l=1#post375911
Are these mk2 versions entirely custom made with CNC, or are these originals with reduced lips?
Hi POS,
These are the original JBL guides. My CNC man says it would be difficult to do clones cheaper than the originals.... We have not scanned them. Maybe Guido has a better “CNC handle”.
However one thing that we discovered is that the JBL forms are not very accurate... We built a jig to fix the guides when we run the CNC machine and my 5 guides seem to come from at least two different cast sessions as we had to re-align the CNC machine to get good results. The 5 axis CNC is VERY accurate.
The material is also odd. The outer form is plastic and that is fine to mill. The filler is odd and eats routers.... -Just turns into dust when milled.
Anyway, now sanded and clear for some paint.
Worth noting is that 3 of the guides has some residual from the cast in the throat and needed some additional work to get smooth. You can check yours by running your finger in the driver opening, they should be completely smooth with no edge. 3 of mine did so that has been sanded off.
Kind regards
//RoB
The solution to the problem changes the problem.
-And always remember that all of your equipment was made by the lowest bidder
Yep I can sense and see a small seam in mine, but it is so small that it cannot affect sound (™), and sanding it would probably require the entire horn to be repainted...
Mineral loaded usually means sand filled in the urethane world. Yahoo! Super destructive to cutting tools and absolute hell on pumps until they figured out how to carry that (mineral) into the product fluid stream post pump.
Barry.
If we knew what the hell we were doing, we wouldn't call it research would we.
Hi
Makes sense that it contains some kind of mineral. Even sanding took some work.
When it comes to the “edge” in the mouth it is easy to remove with fine sandpaper (240). It is only in the inner mouth so it will be barely visible from the outside. And if you go after with (1500) sanding cloth it actually looks pretty much like before but without the “edge”. That is at least what I did.
I choose to believe that is an improvement ;-) . The first two guides from January did not have that edge…
I will have to repaint the upper and lower edges for sure, but I’m not planning to repaint the entire guides for the pair without the 045 horn.
I may have to repaint the whole of the 3 guides with the 045 horns as one of the guides needed some polishing after milling the 045 horn mount. -Why not in White….
Kind regards
//RoB
The solution to the problem changes the problem.
-And always remember that all of your equipment was made by the lowest bidder
Always an interesting project, glad to see it continue. Keep up the good work.
Hi all,
Short update.
Too much food and “Christmas” have reduced time in the work shop. Small progress have been done and the all the M2 horn are back after treatment. 3pcs are milled for JBL 045Ti-1 horns and drivers and all 5 pcs are milled for reducing baffle area as mentioned above.
The material is difficult to work with and I will see if I can polish the end surfaces or if I have to repaint them. -More info next week.
Three of them are going into the HT as new builds and 2 are going into 2 channels speakers to my other system.
On the 2 channel system some progress has been made. As mentioned above I will use LE1400H woofers and they just came back with new surrounds. -Brilliant job from LN Högtalarservice, they are as new (well... they are new).
I decided to build them using a pair of old stock JBL SP215-9 cabs I had and have braced them and will add new baffles to them this week. There will be a new baffle for the M2 waveguide on the box in the Picture and an separate elevated baffle for the LE1400 to bring them into plain level (pics will follow). The M2 will not have any cover, but the LE1400's will have a steel mesh/foam cover.
I hindsight it would probably have been easier to build new ones… The cabs are built in plywood and now reinforced with bracing and additional improvements.
They are about 60 litres (about 2 Cu Feet) net which may prove a little short on the LE1400’s. I plan for two 3” ports at the bottom. –Have not had time to run numbers so far and it may prove that the ducts will be longer than the depth of the cabinet to get to Fs 27Hz…. Some damping will bring perceived volume up to maybe 70 litres. Inputs here are very much appreciated,
A "scilent" Crown CTS4200 amp with an built in BSS Omnidrive unit is prepared and is standing by to be engaged. An excellent amp and with built in full BSS capabilities, easily a match for the new HD series except for “sheer power”. I would even argue that the CTS series may be better that the HD series for HiFi use, as for the power it is not really needed in home Environment, the CTS crank out above 4x200w RMS.
More info will follow.
Kind regards and Happy New Year
//RoB
The solution to the problem changes the problem.
-And always remember that all of your equipment was made by the lowest bidder
Can't wait to see the result!
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