I don't know what kind of hot glue you use but I have glue that I applied 5-6 years ago and it is still just as pliable as the bendy unused sticks I have.
This glue/caulk is going on the inside or outside of the box on the frame? and how thick is it going to be to provide mass addition? Hot glue doesn't appear to be very heavy...
I don't know what kind of hot glue you use but I have glue that I applied 5-6 years ago and it is still just as pliable as the bendy unused sticks I have.
What is said brand? I have used the cheap crap from Harbor Freight tools to no gokd ends. The Stanley is a little better, but it, too got hazy after a while and hardened up, ultimately falling off. This was on crossover boards.
I looked and I have been using the Stanley brand. I found a big glob I applied a few years ago inside an enclosure to secure driver wiring.. It is stiffer than I remembered, although still flexible enough. Maybe it would work on a driver frame, maybe not.
So I ended up with an approximate 4th LR around 1500-1600 Hz. Impedance is pretty benign, phase does not exceed +/-45 degrees anywhere and it is a true 8 ohm design.
Here is an on-axis with impedance overlaid:
The response generally tilts downward, and peaks and valleys are about equal.
This is the impedance plus phase:
Should be a very easy speaker to drive, at least as regards demands on the amplfier. No radical swinging, no radical phase angles. If this speaker was at all sensitive, it would do just fine with teh toobz.
I think this is the current crossover iteration, if not - it is pretty close (I may have swapped a 20uF in for an 18uF on the woofer circuit), and definitely good enough to give an indicator of the distortion performance. Amanda is sleeping right now, and 90db sine sweeps are not her preferred wake up call.
Below 250 Hz or so cannot be trusted, but as you can see 3rd order is -45db or greater at 90db/1M. This is a pretty fricken loud sine sweep, actually, and pushed my test amp. This is not an overly sensitive speaker - I am guessing 82-83 at best. The big air core coil I used on the low pass eats up plenty of amplifier juice on it's own. This is the woofer that yields the weird impulse, by the way.
I'll update with bass models, and a few more measurements later today. Looks like rain, and I need to mow.
One more showing the reverse null. I thought about doing a little more work on the woofer roll-off to further reduce its output above the crossover point, but for now I am leaving it as-is.
Here is the extension and excursion modeled to 96db, or - after baffle step loss approximately the level at which I did the distortion sweep. Ended up around 10 watts.
F3/6/10 of 52.6/46.7/41 respectively. Slight ripple centered at ~70Hz, but it is only about 1db.
Excursion at 10 watts:
As you can see, at loudish listening levels - no worries about the cone going bye-bye. Well, unless you are listening to the T-Rex foot stomps in Jurassic Park at 90db.
Here it is at 50 watts (welcome to the deaf zone):
This would be in the 96-98db range, so pretty damn loud.
Here it is with 100 watts and a 50 Hz 2nd order highpass filter applied:
With the highpass in place, F3/6/10 is now 56.2/50.8/45.4 respectively. So, in order to play these at ear destroying level without exceeding stated Xmax you will need a 50Hz 2nd order highpass filter in place and 100 watts of horsepower.
Here it is with an 80Hz highpass filter in place:
And the excursion:
So if you run with a subwoofer and want to deafen your ears and compress your inner organs and cause some damage to the sheetrock, get a seriously big amp and add a highpass of 80Hz.
For shits and giggles, here is four of them in a 30 liter vented cabinet with 800 watts:
So a Behringer iNuke and some earplugs and eight of these drivers would probably suffice as the midbass section of a world class home theater LR stage or even as the midrange section on a stage setup. Of course, I am convinced the voice coils would weld solid before 200 watts comes pouring in them, but it is fun to model and see those bigass numbers.
One of the things I always told JR about his speakers was that they were indestructible. That's sort of how Barbie Girl @ 100+db and dub step torture tracks evolved in our house tracks. Good stuff JR. Can't wait to hear these!
Seriously though, I think we found the limit of this woofer. The cone got pretty warm, and we bottomed them a few times. Compelling argument for a better frame design with more cooling, and a bumped back plate to keep the VC from hammering.
I think using a real frame and either tightening suspension to keep it from bottoming or adding a bumped backplate would be swell. There are better engineered drivers out there in the $30-40 class.
Can't seem to find my distortion graph. I've got driver #2 to measure so I should be able to repeat sometime this weekend. I did spend a bit of time pushing down the breakup a bit more. One note, these measurements are with the grills on.
First graph is the DSA 175 by its self. Seems like I've got something going on with those upper freq spikes (rattles). Didn't have time to track those down.
Goofy impulse window from omnimic. Not sure how to fix that. Bottom graph is my current design. Sorry JR not much you can take from this...
Comments
I am pretty happy with the crossover I have in place, and will be sharing that up pretty soon - along with associated measurements etc.
Here is an on-axis with impedance overlaid:
The response generally tilts downward, and peaks and valleys are about equal.
This is the impedance plus phase:
Should be a very easy speaker to drive, at least as regards demands on the amplfier. No radical swinging, no radical phase angles. If this speaker was at all sensitive, it would do just fine with teh toobz.
I think this is the current crossover iteration, if not - it is pretty close (I may have swapped a 20uF in for an 18uF on the woofer circuit), and definitely good enough to give an indicator of the distortion performance. Amanda is sleeping right now, and 90db sine sweeps are not her preferred wake up call.
Below 250 Hz or so cannot be trusted, but as you can see 3rd order is -45db or greater at 90db/1M. This is a pretty fricken loud sine sweep, actually, and pushed my test amp. This is not an overly sensitive speaker - I am guessing 82-83 at best. The big air core coil I used on the low pass eats up plenty of amplifier juice on it's own. This is the woofer that yields the weird impulse, by the way.
I'll update with bass models, and a few more measurements later today. Looks like rain, and I need to mow.
One more showing the reverse null. I thought about doing a little more work on the woofer roll-off to further reduce its output above the crossover point, but for now I am leaving it as-is.
F3/6/10 of 52.6/46.7/41 respectively. Slight ripple centered at ~70Hz, but it is only about 1db.
Excursion at 10 watts:
As you can see, at loudish listening levels - no worries about the cone going bye-bye. Well, unless you are listening to the T-Rex foot stomps in Jurassic Park at 90db.
Here it is at 50 watts (welcome to the deaf zone):
This would be in the 96-98db range, so pretty damn loud.
Here it is with 100 watts and a 50 Hz 2nd order highpass filter applied:
With the highpass in place, F3/6/10 is now 56.2/50.8/45.4 respectively. So, in order to play these at ear destroying level without exceeding stated Xmax you will need a 50Hz 2nd order highpass filter in place and 100 watts of horsepower.
Here it is with an 80Hz highpass filter in place:
And the excursion:
So if you run with a subwoofer and want to deafen your ears and compress your inner organs and cause some damage to the sheetrock, get a seriously big amp and add a highpass of 80Hz.
For shits and giggles, here is four of them in a 30 liter vented cabinet with 800 watts:
So a Behringer iNuke and some earplugs and eight of these drivers would probably suffice as the midbass section of a world class home theater LR stage or even as the midrange section on a stage setup. Of course, I am convinced the voice coils would weld solid before 200 watts comes pouring in them, but it is fun to model and see those bigass numbers.
I think using a real frame and either tightening suspension to keep it from bottoming or adding a bumped backplate would be swell. There are better engineered drivers out there in the $30-40 class.
JR I've got the same peak (I miss spoke earlier) see attached
These were better received than I expected - I am a harsh self-critic, I think.
Goofy impulse window from omnimic. Not sure how to fix that. Bottom graph is my current design. Sorry JR not much you can take from this...