Those look great!
Rob:)
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Those look great!
Rob:)
They look awesome!!
This is so cool :)
If you get any 045s over when you are finished, I might be interested. One of mine 045Be are faulty.
Short update.
Sorry bubbleboy76, no spare 045's. Check with LN.
Ivica, I have not gotten so far to figure out XO yet. The 1400PRO is clean to about +1200Hz so I might potentially increase to 1kHz XO as I have no bass in these, so very limited cone travel. I don't know if that made any difference when designing M2 but 2216 will have to generate some real cone movement to produce bass.
I have finally started to prepare for the XO and DSP correction file. The JBL M2 file does not seem complicated and in the BSS version, there are 17 PEQ points for each driver but no FIR or phase corrections. That means that the chosen XO points and the cabinet are very well integrated indeed. The delay in the M2 is somewhat surprising long at 271ms. To determine the acoustic delay in mine I just shot an MLS puls on each driver and note the flight time/distance the system gives me to a fixed point (mic) about 2 meters out and use the difference as a basis. Some very advanced tools in the form of a "setsquare" direct on the monitor was used to determine that the peaks matched. Delay was calculated at 125ms for the woofer and 427ms for the 045.
Attachment 85866
A first set of data wa collected out doors with no flat surfaces within 5m, except for the ground. Hight of pole mount was just above 2m. A bit chilly at 10 degrees C, but with a lot of coffee it was fine.
Attachment 85867
I order to get a reference for timbre a very competent monitor in the form of an active Genelec DSP studio monitor was collected. Very valuable to have a good ref. The Genelec is within +/- 1,5db 58Hz to 20kHz with clean phase all the way. That is not too shabby.
Attachment 85868
Attachment 85869
Best reagards
//Rob
Hi Rob,
Nice to be seen that THE PROJECT advanced.
From the point of LF bass response I would not expect any spectacular results from the mentioned drivers even with the larger EQ applied, especially in such small box. From the simulation point using over 150Lit bass-reflex box with 2216nd drivern can reproduce a kind of "usable bass response".
But using 15-inch driver over 500~600 Hz may produce a "directivity" problem, especially if such "wide dispersion" horn as M2, is applied. Using 'smaller diameter driver' would improve such "problem".
Using here 14-inch driver over 1kHz may would introduce , such mentioned "directivity" issue. But as can be seen on JBL EON 615 solution a kind of "slot dispersion bass cover" would be helpful, but 'scalled' to the bass driver size
https://reconingspeakers.com/product...plate-5039904/
I believe that 'pure rectanglar' cover round 8-inch width can sovle "the problem".
Regards
Ivica
The curve for the 1400PRO, even in such small cabinet, is pretty encouraging. Not much bass however. I do XO at 80Hz to the subs.
Here are some measurements
1400PRO in cabinet
1. Nearfield 170ms 3mm
2. Far field 30ms 146cm outdoor
3. Far field 30ms 146cm with EQ outdoor
Attachment 86215
Attachment 86216
Attachment 86217
Here are some measurements for the 2451Be's in cabinet on my butchered M2 horns.Attachment 86218
No smoothing and please check scale change.
1. Far field 6ms 154cm outdoor
2. Far field 6ms 154cm with EQ outdoor
Attachment 86219
Here are some measurements of the 045 on the K2 S9900 horn incorporated into my butchered M2 horns.
Also attached is a system plot on the full system.
All these curves are taken outdoors on a 200cm speaker stand with no reflective surfaces within 5m except a sloping grass area 200cm below.
1. Far field 3ms 145cm outdoor
2. Far field 3ms 145cm with minimal EQ outdoor
3. Far field full system 10ms 157cm outdoor with EQ & LR24 @ 800Hz and 13kHz
Attachment 86220
Attachment 86221
Attachment 86222
Here are a comparison between the old and the new. Slightly bigger but still acceptable by the Government.
Attachment 86223
Attachment 86224
The room is about 5x8m and pretty decent when it coems to modes. 2x JBL SUB1500 subs do low end duty, one at the font of the room and one at the back.
Electronics is still same old fully digital rig with Meridian pre, BSS DSP and Crown CTS amps. Soon to be turned into a museum piece .
Drivers has no protection cap but a 8db attenuator. 045's are rather low sensitivity so they have no attenuator but are protected by a cap as they probably would react negatively on any voltage spike.
This summer I will devote a few days to re-measure and se If I can get the XO's more seamless by playing with the delays and potentially fiddle little with the EQ points.
Attachment 86225
Attachment 86226
Really cool. Nice work.
Nice measurements as well.
I would angle the L and R more inwards to reduce SBIR from sidewalls a bit, but that's just me.
Hi bubbleboy76,
Thank you.
I agree, I would turn them in more if possible.
The sides are both angled both inward and downward as much as the wall mount allows, please see better picture attached.
The angles (down and in) are pretty spot on to where we sit.
Wall reflektions is far from optimal but the M2 WG is pretty nice off axis, better then most alternatives so it is not perceived very sonically disturbing. Maybe I will add some some kind of foam there later.
I can't really move them more inwards either, with this size screen.
Compromises, compromises.
The 045's blend very well with the Be's and allows for limited EQ on the Be drivers. I have no idea if it would have been better to put the 045 horns at the top as in the K2's, or if the centre position is equally good.
I have not seen any documentation outlining which placement is preferred. Probably the top mount as this is what JBL does in the K2s. But that could also be driven by aesthetics. For me it was a matter fitting into a small cabinet.
Fronts are already made and hopefully I can get the cloth on this weekend. They attach with resessed magnets.
I hope to be able to place the M2's better in the 2-channel room.
Attachment 86227
Maybe you can try some temporary thick damping on the walls close to the speaker, just to see what happens.
I would gain from it myself I think, but I can not do it due to WAF, so I donīt want to try it. I donīt want to know what I am missing...
I think you placed the UHF-horns perfectly.
They look great and thank you for sharing all of your work. They make for great reference as well.