Econowave Speakers

[Face]

Face, how do you recommend to measure drivers for importing into PCD? Should I do it in room where the speakers will play, or should I do it outside up high to eliminate as many reflections as possible?   Tom Danley says measure without reflections, then apply filters. What do you do?

For PCD, I measure at 1m with bass traps all around, eliminating all reflections.

[mgalusha]

Face, how do you recommend to measure drivers for importing into PCD? Should I do it in room where the speakers will play, or should I do it outside up high to eliminate as many reflections as possible?   Tom Danley says measure without reflections, then apply filters. What do you do?

Rich,

Not sure it will work any better, but Wayne Parham suggests laying the speaker on it's back and positioning the mic about a meter above it. Doing so outside is of course better. At least that should help sort out if the bump is the speaker or the room interaction. 650Hz is 1' 9" according to the real traps calculator.

mike

Edit: Wayne's measuring suggestions: http://audioroundtable.com/forum/index.php?t=msg&&th=12291&goto=72746#msg_72746

[richidoo]

OK, thanks Face. I'll redo the measurements without echos, and with correct polarity.

The low mid overkill is gone, tweeter is cranked up where it should be so the overall sensitivity is better. The speaker sounds better overall, but I only have parts to mod the one speaker so I'm listening to one. I don't hear the 650 peak and 1200 dip specifically but they're still there.

[richidoo]

mgalusha, thanks for the tip to lay it on back. With controlled directivity it should work great. I had my son talked into helping me hoist it 4 feet up onto a scaffold, so he will be relieved to hear an easier solution.

650Hz = 21"... Hmmmm.... the box interior height dimension is 40.5", but there's no bump at the fundamental 335Hz. Could just be a coincidence.  I think the big horn and big AE driver as obstacles inside the box would diffuse any vertical reflections.

[richidoo]

When measuring the drivers, should I put the mic halfway between their center heights? That is also my listening ear height. Then don't move the mic or test signal gain between woofer and tweeter measurements, right?

Or do you measure each driver on its own axis? Seems like you would lose the phase relationship.
Thanks

[Face]

Even with your listening height, at 1 meter tweeter height should be fine.  But with your C-C distance and being a CD type speaker, 1m may be too close.  Your best bet will be outside and further away. 

[richidoo]

It's been raining from TS Beryl last few days, so I haven't been able to measure outside yet. Tomorrow should be OK.

I am noticing the huge difference in midrange clarity gained by changing the woofer coils. Not only the value changed, from 3mH to 2mH (two 1mH coils in series,) but also the type of coil - the original was 3mH SuperQ iron core. The replacement 2mH are air cores. The midrange muck that I attributed to too much box stuffing is all gone, and I didn't change the stuffing.  It could be from filling in the missing midrange frequencies, and also from removing the magnetic hysteresis of the core, or both. 

I ordered some 2mH and .5mH air core Erse 14ga coils today from PE so I can play around with the values to zero in on what I like. I'll order some pad resistors and parts for BSC from Mouser tomorrow. btw Did anyone see the Mouser Electronics sponsored car in the Indy500? Tony Kanaan came in 3rd in the Mouser car! He might have won if not for last lap accident.

The combination of Radian and AE drivers is great. With the midrange flattened now the intensity and detail is really strong. Still more refinement needed, but there is incredible potential, considering the better horn coming and more crossover tweaks.

Using PCD is teaching me what the various crossover parts do, how they react to value changes. I'm hoping it will be easier to make tweaks by ear. Something I always thought was magic before. You know you're ignorant when something looks like magic.

[Face]

I wouldn't use a Super Q higher than the woofer of a 3 way...or any non-air core for that matter.   

[richidoo]

Thanks Mike. I agree, now that I've heard it. Zilch spec'ed cheapest iron cores for the ewave.

[richidoo]

I spent a couple hours outside in the hot sun with the bugs getting some measurements. Measurements are much flatter than inside, plus the mic and gain is same for Woofer and tweeter, and the phases are correct (I think) so sim should be easier and more accurate. The AE woofer had some FR anomolies when playing MLS signal lying down on back. It was fine playing on horizontal axis as intended.

I'll post some measurements soon.

[richidoo]

I got the smaller air cores on both sides now. Do coils need to break in? Sounded a little tight at first. Opening now after a couple hours. I got a couple sizes that will allow fine tuning. I'll need to measure to see the changes.

With the iron cores gone, the bass is much cleaner, the whole speaker sounds much better, and plays louder. The iron cores seemed to really suck out the life and the volume.

So now, of course, with cleaner bass I can hear new LF flaws.     The bass seems slightly resonant, chesty on alto girls and guitar low notes, etc. The box is sized for Q .57 with the Eminence Deltalite 2512, and it's way too big for this AE TD12X driver.  

EPB of this driver is 110. Probably shouldn't be sealed anyway. But that wouldn't make it too warm in the mid bass.

The simulated AE TD12X needs 30 liters for Q .7, 50 liters for Q .57,  75 liters for Q.5.   The box is currently at 120 liters, which spells Q .43    What is the sonic penalty of too large sealed box? I've searched hi and lo for the answer.  Grant me this wisdom, mighty Oracle.

Also, there is minimal fill inside the sealed box now. Usually sealed boxes will have more fill, sometimes even stuffed full. I don't need more volume, so I didn't bother filling it with fluff. But maybe more is necessary to damp the driver better?

More stuffing and smaller box?
Thanks

[richidoo]

Simulations of 30, 50 and 75 liters with AE TD12X.

[Face]

I got the smaller air cores on both sides now. Do coils need to break in? Sounded a little tight at first. Opening now after a couple hours. I got a couple sizes that will allow fine tuning. I'll need to measure to see the changes.

With the iron cores gone, the bass is much cleaner, the whole speaker sounds much better, and plays louder. The iron cores seemed to really suck out the life and the volume.

So now, of course, with cleaner bass I can hear new LF flaws.     The bass seems slightly resonant, chesty on alto girls and guitar low notes, etc. The box is sized for Q .57 with the Eminence Deltalite 2512, and it's way too big for this AE TD12X driver.  

EPB of this driver is 110. Probably shouldn't be sealed anyway. But that wouldn't make it too warm in the mid bass.

The simulated AE TD12X needs 30 liters for Q .7, 50 liters for Q .57,  75 liters for Q.5.   The box is currently at 120 liters, which spells Q .43    What is the sonic penalty of too large sealed box? I've searched hi and lo for the answer.  Grant me this wisdom, mighty Oracle.

Also, there is minimal fill inside the sealed box now. Usually sealed boxes will have more fill, sometimes even stuffed full. I don't need more volume, so I didn't bother filling it with fluff. But maybe more is necessary to damp the driver better?

More stuffing and smaller box?
Thanks

How well braced is the box?  

Want to make them smaller?  Do you have any extra bricks in your yard?  Sand maybe?  

[richidoo]

Thanks Mike. They are well braced. I do have some extra pavers that I could jam in there. But I could not kill off 50 liters with bricks. I can fashion a removable divider board that cuts it down.

Do you think the low Q could be the cause?

I don't gain much more extension below Q.5 anyway.

[Face]

Thanks Mike. They are well braced. I do have some extra pavers that I could jam in there. But I could not kill off 50 liters with bricks. I can fashion a removable divider board that cuts it down.

Do you think the low Q could be the cause?

Yes, it's possible.  A new cab or divider would be your best bet.