Hi All, I have been sound obsessed for a long time but just starting out on speaker builds. My goal with this project was to make the highest SPL 15" cab possible while still getting excellent clarity. These are for DJ use with electronic music and would always be paired with a sub. I want to hear your honest opinions. Cabinets are built from 3/4" pre finished birch plywood. 2.5CF box tuned to 40hz with dual 3" ports measuring 7.33 inches in length. These use an active crossover DCX2496, tri amplification, Neutrik NL8FC. Crossover points 1k and 4k. Here are the drivers:
Low: FaitalPRO 15FX600 15" Professional Neodymium Woofer 8 Ohm
Mid: B&C 6NSM51-8 6" Professional Neodymium Sealed Back Midrange 8 Ohm
High: B&C DE1095TN-8 2" Neodymium Horn Driver 8 Ohm with B&C ME75 2" Constant Directivity Horn 90 x 40
I spent about an hour doing DSP on the DCX2496 and achieved the following frequency response with VAR smoothing. Could likely iron it out more with additional time. Happy to answer questions and do any additional testing.
Low: FaitalPRO 15FX600 15" Professional Neodymium Woofer 8 Ohm
Mid: B&C 6NSM51-8 6" Professional Neodymium Sealed Back Midrange 8 Ohm
High: B&C DE1095TN-8 2" Neodymium Horn Driver 8 Ohm with B&C ME75 2" Constant Directivity Horn 90 x 40
I spent about an hour doing DSP on the DCX2496 and achieved the following frequency response with VAR smoothing. Could likely iron it out more with additional time. Happy to answer questions and do any additional testing.
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I've been thinking of mounting my CD tweeter like that in my home, to save weight to allow me to lift the bass reflex box onto the pole. 84 lb is too much for me at age 72 and 160 lb. But for PA use, a separate horn with no box is a non starter. Think of the inattentive or clumsy roadies. Think of the non-performers wandering around the stage. If on the front of the stage, think of the audience doing mosh pit antics. Chances of damage are significant.
+6 db minus 4 db response @ 400 hz requires more attention. My SP2(2004) are +-3 db.
As a home speaker pair, a good start challenging you to attempt some refinements.
+6 db minus 4 db response @ 400 hz requires more attention. My SP2(2004) are +-3 db.
As a home speaker pair, a good start challenging you to attempt some refinements.
What does the phase response look like?
You need to try that as a 2-way... I'm not sure the 6" mid is adding anything the 2" couldn't do.
You need to try that as a 2-way... I'm not sure the 6" mid is adding anything the 2" couldn't do.
Completely agree this is not a great design for touring. But for in home use or installations I think it has a cool look to it and saves a ton of weight as you say. These weigh 66.4 pounds each for reference. I will see if I can iron out that drop at 400, have not tried yet. Thanks for the response!
I might could use some educating on testing/understanding phase response. Based on what I do know, I used the auto feature on the DCX2496 to do time and phase adjustment. No changes were made to phase. For timing, the High is at 0, the Mid at 284mm and .83ms and the Low at 154mm and .45ms. As for eliminating the 6" mid, that is easy to do with the active setup so I will give that a shot and see how it changes the sound and frequency response. Thanks for the response!
Those delay setting sound reasonable, people say the auto alignment system in the DCX flat out doesn't work but in my experience it's pretty good.
FWIW I have some B&C DE750's (cousin to the DE72.. uses the same diaphram) paired with dual 15" mid/bass drivers with a 1khz/24db LR crossover and it is smooth and has no problem "keeping up", and I'm also using the DCX for processing.
FWIW I have some B&C DE750's (cousin to the DE72.. uses the same diaphram) paired with dual 15" mid/bass drivers with a 1khz/24db LR crossover and it is smooth and has no problem "keeping up", and I'm also using the DCX for processing.
Is there a way to test the delays the DCX came up with and verify? And I had a feeling the CD I chose for this build had enough room to run a couple mid bass drivers. I figured the first comment would be "why such a powerful CD for one 15" but that comes from lack of experience on my part. Something I could use some help with, how do I figure out what the limits of the speaker are? And if I can find those limits, maybe I can program in a limiter on the DCX?
Apparently there are tools in a newer version of REW, I don't think the version I have includes them as I don't recall seeing it so I may be overdue for an update. Have a look at this video.. Link
Big CDs like this are always going to have more output capability than reflex loaded mids and mid/bass drivers, and that is a good thing. The benefit these 2" exit CDs provide is the ability to use a much lower crossover frequency which counters the narrowing polar response that a larger mid/bass driver produces at higher frequencies, and this results in a much more uniform polar response for the speaker system as a whole.
You don't have to worry about finding the power handling limits of them either, in most cases the subs are going to be the section that runs out of headroom first, and to prevent the sound from becoming unbalanced(more mid & highs than lows) the limiters for all other outputs should activate at the same signal level as the sub outputs.
Thanks for this good to know!
OK so I eliminated the 6" and everything between the 1000-3000hz range sounded super tinny. Took away the warmth and changed the sound pretty dramatically. Although I did not try eliminating it, checking the frequency response with REW, and making DSP adjustments. Maybe I should try that before jumping to conclusions. I purposely did this build as an active crossover and tri amp so I could do these kinds of experiments.
Are you saying you just removed the mid and didn't change any of the processing? If so that won't work. Try a sweep of the CD from 1khz up(with crossover), there will more mid output than topend but EQ will have a dramatic effect.
Hopefully you adjusted the crossover for 2-way! Coincidentally, I was doing some experiments yesterday with crossover points/slopes with dBx Driverack PA2 active crossover for my 2-way horn+woofer setup, and changing the crossover filter/slopes had a large effect on SQ. In general, my ears seem to much prefer 18dB slopes over steeper ones and probably prefer Butterwoth over Likwitz-Riley.. Worth experimenting in your room/setup.
Very curious what the crossover looks like here. Seems like a nice build otherwise. The 400hz null is probably a room thing, but it could also be crossover related. Nice job overall, especially for a first attempt.
The mid driver itself is probably a little weak in the 400 Hz range. 15’s tend to run 96, 97 dB sensitivity, 6” tend to run 3 to 4 dB lower. That’s why you often see two used instead of one. And if it’s sealed back it may be rolling off in the 400 Hz range. You may need to bump the overall mid level up, reduce the order of the high pass feeding it or lower its frequency (leaving the woofer where it is). Then shelve the rest of the mid response back down a bit.
With electronic music a midrange dip isn’t the end of the world, nor does it take a buttload of power there. So not correcting it or correcting it are both valid options.
With electronic music a midrange dip isn’t the end of the world, nor does it take a buttload of power there. So not correcting it or correcting it are both valid options.
If staying with the three way design, look at lowering the crossover frequency between the 15 and the 6 inch maybe to around 400Hz.
Also experiment with "under lapping" the crossover points some.
Also experiment with "under lapping" the crossover points some.
Good effort. I personally would cut the 1khz to 2khz by 3db, and 150 to 350 by 3db.
Are you sure there isnt a protective high pass filter set on your xover unit? Because it looks like it needs a serious low end boost currently about -4 or -5db at 50hz dropping further to about -20 at 40hz. This would be bad for modern techno or drum and bass. That said if you don't listen to that or anything with deep bass it would probably be fine.
Are you sure there isnt a protective high pass filter set on your xover unit? Because it looks like it needs a serious low end boost currently about -4 or -5db at 50hz dropping further to about -20 at 40hz. This would be bad for modern techno or drum and bass. That said if you don't listen to that or anything with deep bass it would probably be fine.
That is correct I just moved the crossover point effectively eliminating the 6" without changing any processing. I will eliminate, do a sweep and see how that sounds.
No passive crossover, only active using DCX2496, crossover points at 1000 and 4000. Is that what you are asking? Thanks for the comments!
Since this is tri amped I could make up for a the sensitivity difference by bumping the amp right? I think that is what you meant by "bump the overall mid level up" and then I could make further adjustments if parts of the mids were too high as a result. Thanks for the comments!
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