You won't see the issue unless you test for it properly. Seal up a woofer from the front to the baffle and play a test tone.....now run a gated measure on the tweeter and mid and compare with and without the woofer playing........with ribbons and planars the results are vey eye opening so you get an idea of the destruction at play during complex music. The baffle would have to be extremely dense and non resonant (read expensive and heavy) to alleviate the effects........and it's not hard to implement in construction
Yes........body to woofer box will be sealed across the face fof the woofer box and a layer of thick neoprene to eliminate the transfer of vibration......i plan on a nice grill to cover the fasteners and slots anyways.
From post #102 per xrk:
"It could be shorter as there is extra height on baffle above tweeter that could be trimmed a few inches."
That said, what can I get away with?
Attached is a 42 inch high version. I also changed the shape of the baffle above the top of the flanking wings to give it a slimmer look. Will that baffle change affect the crossover?
"It could be shorter as there is extra height on baffle above tweeter that could be trimmed a few inches."
That said, what can I get away with?
Attached is a 42 inch high version. I also changed the shape of the baffle above the top of the flanking wings to give it a slimmer look. Will that baffle change affect the crossover?
Attachments
The passive XO is the only way I can have any assurances that the crossover and voicing is as I designed. When you do active DSP XO, I can tell you the crossover frequency points, but the voicing and slopes and integration of the drivers to be smooth in phase space is really all yours. There is no guarantee that it will sound like how I designed it.
But it may work fine.
But it may work fine.
Thank you very much, one of the reasons I have not gone in either direction.....always a "but" to deal with....and budget as well as time, again do to all out RV remodel project that keeps growing in scale as we go.
I may of missed seeing the numbers, can you let me know what the slopes are you picked for tweeter to mid and mid to woofers. The Xkitz are 24 db, pretty steep slopes so possibly not a good fit.
I did see though cannot recall the details, 12 db to the woofers with a natural roll off of 12 db, if I am correct, that could work out, maybe that is.....
It is pretty shocking the differences there can be going from 6, 12, 18, 24 dB slopes, I have had good luck in mobile audio getting the bass from the rear up on the hood just using slope change.
Idea: I want to bi amp so bi wired between mids and woofers using the right passive values might work out though as you have mentioned I would have to figure those out on my own and I can do that.
I sure as heck hope these work out in our RV, will do whatever room treatments I can to help.
Thanks
Rick
I may of missed seeing the numbers, can you let me know what the slopes are you picked for tweeter to mid and mid to woofers. The Xkitz are 24 db, pretty steep slopes so possibly not a good fit.
I did see though cannot recall the details, 12 db to the woofers with a natural roll off of 12 db, if I am correct, that could work out, maybe that is.....
It is pretty shocking the differences there can be going from 6, 12, 18, 24 dB slopes, I have had good luck in mobile audio getting the bass from the rear up on the hood just using slope change.
Idea: I want to bi amp so bi wired between mids and woofers using the right passive values might work out though as you have mentioned I would have to figure those out on my own and I can do that.
I sure as heck hope these work out in our RV, will do whatever room treatments I can to help.
Thanks
Rick
Changing baffle shape will definitely affect the XO. The key rules to preserving a proven crossover are: (1) use same drivers; (2) keep CTC distance and baffle offset the same; (3) do not change the shape or width of the baffle. The latter affects the frequency extension and diffraction. It may be minor but won't be the same. Changing the shape of the wing will affect bass extension. If you make it deeper that is fine but not smaller.
One last design deviation question and then I’ll leave you alone if you don’t mind?
So the resonances from the stamped steel baskets. Adding the damping material to the frames was certainly an excellent mitigator…..but what if the drivers all faced inwards?…..wouldn’t the forward output be cleaner with just the cone output?…..any high frequency resonance from the back sides could be damped out/down with absorbing material within the winged chamber? The volume of the slot could be adjusted to compensate for the magnets by making it thinner, no?
You can try it, but the reason magnet goes in on one is mostly to negate suspension induced distortion. As one moves in the other moves “out” even though still in. So whatever distortion there is one direction, its pair is doing the opposite. You can see this is the -50dB or better harmonic distortion.
If you made it cone facing in on both, it might actually sound sweeter with higher second order distortion due to asymmetry.
It’s probably not a huge difference but I never measured it.
If you changed the chamber volume it may affect the upper bass crossover point. Definitely changing the slot dimensions will change that.
If you made it cone facing in on both, it might actually sound sweeter with higher second order distortion due to asymmetry.
It’s probably not a huge difference but I never measured it.
If you changed the chamber volume it may affect the upper bass crossover point. Definitely changing the slot dimensions will change that.
"If you changed the chamber volume it may affect the upper bass crossover point. Definitely changing the slot dimensions will change that."
agreed and that's why i mentioned having to adjust the slot volume to counter the removal of the magnets and cone displacement if i decide to do all in firing.
I suppose once built, i could try it both ways and measure just to see if there's a measurable difference.
Did/Does NP have an opinion on SLOB loading that's relevant to the option?
agreed and that's why i mentioned having to adjust the slot volume to counter the removal of the magnets and cone displacement if i decide to do all in firing.
I suppose once built, i could try it both ways and measure just to see if there's a measurable difference.
Did/Does NP have an opinion on SLOB loading that's relevant to the option?
Yes the exit aperture area of the slot should be maintained.
Don’t adjust the depth as that affects the 1/4 wave cancellation frequency. The slot depth as designed allows for a 470Hz woofer low pass fall off from the depth. If you make it deeper (for example to fit an 8in woofer) that changes to 370Hz. So that affects the XO frequency.
It sounds like you like you are a tinkerer and not a by-the-book plan builder, if I understand your thinking based on these questions. I would suggest you go the active DSP route and you can account for the changes in the mechanical design of the speaker if you choose to modify it.
If you want to use the passive XO as-designed (the schematic and parts have to be purchased as a kit from my shop as this is a commercial speaker that I designed with assistance of business partners), then you should stick to the mechanical dimensions as close as possible. Especially: driver to driver CTC distances and locations, baffle width, wing depth and shape, woofer apertures, woofer chamber depth, tweeter and midrange rebate depths and brand and model of drivers. These all affect the specific XO as designed. But if you go active DSP, you are in your own as to filter development etc. I can only suggest XO points and slopes. You can see all that from the XO response curve on post 1.
Don’t adjust the depth as that affects the 1/4 wave cancellation frequency. The slot depth as designed allows for a 470Hz woofer low pass fall off from the depth. If you make it deeper (for example to fit an 8in woofer) that changes to 370Hz. So that affects the XO frequency.
It sounds like you like you are a tinkerer and not a by-the-book plan builder, if I understand your thinking based on these questions. I would suggest you go the active DSP route and you can account for the changes in the mechanical design of the speaker if you choose to modify it.
If you want to use the passive XO as-designed (the schematic and parts have to be purchased as a kit from my shop as this is a commercial speaker that I designed with assistance of business partners), then you should stick to the mechanical dimensions as close as possible. Especially: driver to driver CTC distances and locations, baffle width, wing depth and shape, woofer apertures, woofer chamber depth, tweeter and midrange rebate depths and brand and model of drivers. These all affect the specific XO as designed. But if you go active DSP, you are in your own as to filter development etc. I can only suggest XO points and slopes. You can see all that from the XO response curve on post 1.
I am a DIYer……but your design is solid and I don‘t intend to move far enough away to not be able to use your existing XO. The GRS drivers are proven by you….they produce the tactile experience clearly……..I just think the sub 400hz including the 200hz ring could be better……and I couldn’t live with the wings screwed on….the woofer module will need to removable…..probably 4 bolts and inserts through the bottom and three bolts and inserts through the baffle into the woofer module……I would cover the slots with a grill anyway and not give the grandkids a new parking place for their toy cars! Lol
The removable woofer array with 10 bolts or screws from the baffle and foam gasket between woofer array and the baffle in back should do the trick. The grill will cover the screw holes. But sometimes screws are not so bad looking. I have lots of speakers with screws on the front and it looks good.
A quick question before I begin assembly…..time alignment?…..is there any advantage to have the mid and tweet on a separate baffle farther back and aligned with the acoustic centers of the 8 woofers? Considering the high XO point of 450hz, seems to me this would help to solidify the detail
I didnt like the screws either, and put a lot of thought into that. Yes, I went path of least resistance and screwed them on.
Will like seeing how you tackle the removable assembly. They do sound really good.
Indeed it would help time alignment between the woofer array and mid/tweet (which are time aligned). But that would change the crossover. You would have to do you own woofer to mid XO. The time alignment of the woofer array is less important in this speaker as it is a dipole and uses direct and reflected sound for bass - which comes from all angles after it reflects off rhe back and side walls.
This speaker's breaking is STILL on going! Midrange cleared up in few days, but continuing to improve. May be there now? Bass is broken in, seems to have reached a point I can't detect further change. The highs, while not as wicked as midrange break in, continues to improve.
Sounding fine all around at this time. I guess I need to put the feet on.
Russellc
Sounding fine all around at this time. I guess I need to put the feet on.
Russellc
Ever since I had them up and running, If at home running until bed, work days from 5 PM until bed. Basically, I wasnt thrilled with highs, but they were last to really sound good. At first, some highs had a bit of a sizzle, but has sweetened up remarkably. I would love to hear this top and mid, properly matched
to my JBL bottom....way above my paygrade, and really no need. I dont think anyone that builds would be disappointed, so if on fence, just jump.
Russellc
to my JBL bottom....way above my paygrade, and really no need. I dont think anyone that builds would be disappointed, so if on fence, just jump.
Russellc