That's starting to remind me of something that I've seen before.
Here it is:
Sanders 10b Electrostactic Speakers Review
Looks like a cool project, I like the scale of it, will not take over your living space.
actually, I think the two are significantly different
Ok, so I've experimented some more, trying different combinations of stuffing. I can get rid of the box reflections just fine but there's still a huge dip in the lower frequencies. I've got a nice peak at around 50hz but somewhere between 60 and 70 the sound's almost completely cancelled out.
I'm hoping to fix this by adding bracing but I'm not sure where to start. Brace the sides, divide or driver first? Which is most likely to be the problem? Or am I expecting too much bass and should I just try to remove the peak around 50hz?
I'm hoping to fix this by adding bracing but I'm not sure where to start. Brace the sides, divide or driver first? Which is most likely to be the problem? Or am I expecting too much bass and should I just try to remove the peak around 50hz?
I did some listening tests a few days ago and those were the numbers I came up with. After fixing up the box a bit today (bracing, damping, sealing a bit more) and playing around with the equalizer in winamp, it seems my focus was way off. The bass is alright (the big peaks are likely from the room I'm playing in), it's the mids that are too powerful, for me at least. I've replaced the 1,8 ohm resistor in the notch filter with a 2,2 ohm now and, although the mids are slightly attenuated they're still a bit too strong for me. Could I improve the situation with some more damping, or should I just go with a higher valued resistor (2,7 or even 3,3 ohms)?
It should be noted that I've not broken in these drivers yet, so perhaps I should wait a bit. How long does the EL70 usually need? I know the Fostex drivers require several tens of hours before settling.
It should be noted that I've not broken in these drivers yet, so perhaps I should wait a bit. How long does the EL70 usually need? I know the Fostex drivers require several tens of hours before settling.
Alright!
I've spent the last few weeks working on my Desktop XLs and I think I'm getting close. I found out there were some major resonances in the back and top of the box at around 170 Hz, so I added a shelf brace at the top of the "funnel" against the back, and a smaller brace between that one, the back and the top. This proved enough of an improvement to get me to start building the second of the pair.
Not wanting to have the same issues again, I braced this one more (see pictures below) and all seemed fine. I've now spent the last couple of weeks moving stuffing around, trying to get at something that sounds "wrong" with them. The greatest improvements I've made is adding an extra sheet of plywood to the top half of the back (~33 cm down, since that what I had left of the wood I'd cut) and removing most of the stuffing.
I've now two layers of stuffing in the closed end, and about the length of the closed end of stuffing in the open end. My room has some terrible modes and I've placed the speakers pretty close to the back wall, so this amount of stuffing keeps the bass in check.
What I'm now experiencing is what "sounds" like an out-of-phase problem, either between the speakers or between the port and driver of the second speaker. It's very hard to pin-point but my brain is going crazy when I listen to them. I've come up with the hypothesis that I added too much bracing to the other speaker, causing them to act differently enough to be a problem. My only other idea is that I've messed up the taper on one of them enough to mismatch.
Could the added bracing cause this? I'm all for trying to remove some of it, but I'd rather not go in if it's likely something else.
The first picture shows just the shelf brace. The first speaker has just this (placed slightly higher) and a smaller brace between that brace, the back and the top, forming a sort of an L. The second picture is the complete bracing of the second speaker. It's got a much larger brace from front to back and for some reason a small brace halfway down the "funnel".
I've spent the last few weeks working on my Desktop XLs and I think I'm getting close. I found out there were some major resonances in the back and top of the box at around 170 Hz, so I added a shelf brace at the top of the "funnel" against the back, and a smaller brace between that one, the back and the top. This proved enough of an improvement to get me to start building the second of the pair.
Not wanting to have the same issues again, I braced this one more (see pictures below) and all seemed fine. I've now spent the last couple of weeks moving stuffing around, trying to get at something that sounds "wrong" with them. The greatest improvements I've made is adding an extra sheet of plywood to the top half of the back (~33 cm down, since that what I had left of the wood I'd cut) and removing most of the stuffing.
I've now two layers of stuffing in the closed end, and about the length of the closed end of stuffing in the open end. My room has some terrible modes and I've placed the speakers pretty close to the back wall, so this amount of stuffing keeps the bass in check.
What I'm now experiencing is what "sounds" like an out-of-phase problem, either between the speakers or between the port and driver of the second speaker. It's very hard to pin-point but my brain is going crazy when I listen to them. I've come up with the hypothesis that I added too much bracing to the other speaker, causing them to act differently enough to be a problem. My only other idea is that I've messed up the taper on one of them enough to mismatch.
Could the added bracing cause this? I'm all for trying to remove some of it, but I'd rather not go in if it's likely something else.
The first picture shows just the shelf brace. The first speaker has just this (placed slightly higher) and a smaller brace between that brace, the back and the top, forming a sort of an L. The second picture is the complete bracing of the second speaker. It's got a much larger brace from front to back and for some reason a small brace halfway down the "funnel".
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Alright!
I've spent the last few weeks working on my Desktop XLs and I think I'm getting close. I found out there were some major resonances in the back and top of the box at around 170 Hz, so I added a shelf brace at the top of the "funnel" against the back, and a smaller brace between that one, the back and the top. This proved enough of an improvement to get me to start building the second of the pair.
Not wanting to have the same issues again, I braced this one more (see pictures below) and all seemed fine. I've now spent the last couple of weeks moving stuffing around, trying to get at something that sounds "wrong" with them. The greatest improvements I've made is adding an extra sheet of plywood to the top half of the back (~33 cm down, since that what I had left of the wood I'd cut) and removing most of the stuffing.
I've now two layers of stuffing in the closed end, and about the length of the closed end of stuffing in the open end. My room has some terrible modes and I've placed the speakers pretty close to the back wall, so this amount of stuffing keeps the bass in check.
What I'm now experiencing is what "sounds" like an out-of-phase problem, either between the speakers or between the port and driver of the second speaker. It's very hard to pin-point but my brain is going crazy when I listen to them. I've come up with the hypothesis that I added too much bracing to the other speaker, causing them to act differently enough to be a problem. My only other idea is that I've messed up the taper on one of them enough to mismatch.
Could the added bracing cause this? I'm all for trying to remove some of it, but I'd rather not go in if it's likely something else.
The first picture shows just the shelf brace. The first speaker has just this (placed slightly higher) and a smaller brace between that brace, the back and the top, forming a sort of an L. The second picture is the complete bracing of the second speaker. It's got a much larger brace from front to back and for some reason a small brace halfway down the "funnel".
It may well be too late to get inside these boxes again; if not, or on future builds of this design ( we've got some enclosures that took 3 or 4 "proofs" to nail down ), you'd probably get much better overall bracing results by orienting the two pieces shown in your picture vertically (so as to provide a narrow cross section to the line), as well as to run bracing on both sides the the fold panel. (see red lines in attached PDF sketch for a representation)
Dimensions are not included on this drawing; it's 60" tall and approx 14"wide, so the rear mouth is a rather large opening that benefits significantly from the angled lateral brace.
I think I'm quite screwed trying to redo the bracing (it's all glued up) but I could try and see. Whatever I put in needs to fit through the driver opening (the horizontal shelf did, barely, which is why I put it in initially).
Just to be clear: you're saying the biggest issue with my bracing is the horizontal shelf and that this could be the cause of my problems? What about the little one halfway down. It's not full width, but it'll probably be the hardest one to get out if I go down that route.
Worst case scenario and I'll rebuild one of them to match the other, so they at least behave similarily. These are "just" a practice build but it would be nice to actually end up with something usable.
Just to be clear: you're saying the biggest issue with my bracing is the horizontal shelf and that this could be the cause of my problems? What about the little one halfway down. It's not full width, but it'll probably be the hardest one to get out if I go down that route.
Worst case scenario and I'll rebuild one of them to match the other, so they at least behave similarily. These are "just" a practice build but it would be nice to actually end up with something usable.
I kinda think so - they're choking the cross section area of the line with predictable effects - if this was a sealed box you'd likely have no issues.
just keep the direction of bracing in mind for any future QW action based buildsWorst case scenario and I'll rebuild one of them to match the other, so they at least behave similarily. These are "just" a practice build but it would be nice to actually end up with something usable.
I hacked out the big, vertical brace using force, a hammer and a bit of plywood (mostly to get at the other braces). I also managed to get to the small, half-width brace I'd put halfway down the "funnel" (what is the right term for this? Is there one? ) by running a length of speaker wire down one side, then back up the other side and then pulling at it while sitting on the speaker.
The last change did the trick. That little bit of wood completely ruined the sound from that speaker. I might look at reworking the bracing completely, but already they sound really good. I've also moved them out into the room a bit, and a bit closer together. Now I've got both good bass and a nice focus at my listening position. Hooray!
I wouldn't advice picking 12mm over 15mm, but if it's that or no speakers, it can be done and the results will be far from horrible.
) by running a length of speaker wire down one side, then back up the other side and then pulling at it while sitting on the speaker. The last change did the trick. That little bit of wood completely ruined the sound from that speaker. I might look at reworking the bracing completely, but already they sound really good. I've also moved them out into the room a bit, and a bit closer together. Now I've got both good bass and a nice focus at my listening position. Hooray!
I wouldn't advice picking 12mm over 15mm, but if it's that or no speakers, it can be done and the results will be far from horrible.
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