Klh 17

[Paratima]

Jah! Radius-turn 90's.

Waiting, more or less breathlessly. Building all sorts of strange cables for Spkr Wrkshp.

 

[Zilch]

Where did you get the numbers? PE? Goldwood spec sheet? I've seen some stuff on mfg spec sheets that was so far off it looked like a different driver.

BB6P database includes two sets of T/S parameters, 2005 (left and black) and 2000 (red):

That is weird. I would think you'd have to have a monstrously high Qt for the driver to not show an effect from a box that size.

Just measured them: Fs = 39.5, 40.52; Qes = 0.957, 1.54; Qms = 5.580, 5.356; Qts = 0.816, 1.119; very different from what PE says they are, which matches the 2005 BB6P spec:

http://www.parts-express.com/pe/pshowdetl.cfm?Partnumber=290-324

I believe the high Qs explains how they measure:

I'll confirm the measured T/S on the second unit.

Any suggestion where to tune these for power handling?

Edit: Fs, obviously.

Also, same nearfield results as a month ago:

 

[SPL db]

 

[Zilch]

I HATE these.

[Sound good freespace, tho.... :tongue: ]

 

[Zilch]

DC250-8 Revisited, Vented:

Listening.

Complete specs pending.... :yes:

 

[vinylisfinal]

henry kloss is spinning in his grave!!

 

[Zilch]

henry kloss is spinning in his grave!!

Perhaps, but I guarantee he's also tappin' his toes to "Burning Down The House" right now....

"Take Me To The River"

 

[GordonW]

Leveling the rising response of the Goldwood GW-10PC/8 in this alignment lowered its sensitivity to ~85 dB, and the Selenium D220Ti required ~24 dB total HF comp and attenuation using the E'Wave crossover at 1.88 kHz to balance with it.

So, at least IMHO, it looks like the Dayton DC250 kicks its butt.

That's not surprising, to me... that Dayton Classic woofer is remarkably easy-to-use and very tractable, IME.

Regards,
Gordon.

 

[GordonW]

That is weird. I would think you'd have to have a monstrously high Qt for the driver to not show an effect from a box that size.

That's EXACTLY what I expect is going on, with the Goldwood driver.

Almost every other Goldwood driver has had this situation... no matter what they SAY the Qts is, it's usually somewhere over .6!

Good for IB or OB, but not for much else...

Regards,
Gordon.

 

[Paratima]

I've been researching alternatives on our sponsors' sites. I know it's late in the game and I don't have any information other than published specs, but there are two other 10" woofers at PE that don't look too bad.

There's: Pioneer #1. Looks to be a PA model.

And: Pioneer #2. Higher class and a bit more expensive, though not exorbitantly so.

Fs, Qts and SPL all look to be in the right zones, esp. on #2. Xmax is a bit low on both, but I'm not sure how important that is. Both are higher SPL. No curves published on either.

Anyone know anything about either of these?

 

[Zilch]

That's EXACTLY what I expect is going on, with the Goldwood driver.

Almost every other Goldwood driver has had this situation... no matter what they SAY the Qts is, it's usually somewhere over .6!

It's been a head-scratching adventure tracking it down. I should have measured Fs and Q first thing.

It'd sure be neat to find a modern driver that worked closed-box in these, fit the cutout, had decent response through 2 kHz, good power handling down at 40 Hz in that alignment, and was dirt cheap....

I've been researching alternatives on our sponsors' sites. I know it's late in the game and I don't have any information other than published specs, but there are two other 10" woofers at PE that don't look too bad.

Next step is to put the T/S parameters for each into a box modeling program and compare how they perform in comparison to DC250-8, closed and vented, 0.9 cuft.

DC250-8 does come in ~4 dB more sensitive than the Goldwood, even using essentially the same lowpass filter. You can see it has a bit of a rising response, as well. You can also track how I reduced the attenuation in the E'Wave highpass to compensate by comparing the two schematics.... :yes:

 

[dew042]

This is blasphemy. Seems to me that if installing new drivers and making ports are want you want to do, maybe a new enclosure is in order as well?

dew.

 

[Zilch]

This is blasphemy. Seems to me that if installing new drivers and making ports are want you want to do, maybe a new enclosure is in order as well?

Naw, we're bein' environmentally conscious here, is all.... :thmbsp:

 

[Paratima]

DC250-8 does come in ~4 dB more sensitive than the Goldwood, even using essentially the same lowpass filter. You can see it has a bit of a rising response, as well. You can also track how I reduced the attenuation in the E'Wave highpass to compensate in comparing the two schematics.... :yes:

Erm... to the extent that I understand those things, yes indeedy. Just keep on truckin' & I'll catch up!

Naw, we're bein' environmentally conscious here, is all....

Que quiere decir, en otras palabras, "Enclosure & Grill Cloth Recycling". Si?

So... I guess the next question is, "Do the published specs for the Pioneers indicate a significant improvement and are they anywhere near reality?" My wallet likes #1 better, but #2 looks like it's got more sizzle. Well, come to look at it again, it's $60 for the pair vs $80 for the other - about the difference between the D220Ti and the D210Ti. It does add up. That it does.

 

[Zilch]

Que quiere decir, en otras palabras, "Enclosure & Grill Cloth Recycling". Si?

Something like that, yes; I recognize and acknowledge other available options, and that what I do may be an affront to prevailing restorationist sensibilities.

My mission, if it may be suggested I have one, is to demonstrate that modern performance may be achieved in vintage packages, and I do not apologize for offering up this alternative; it is clearly NOT a casual endeavor on my part.

These KLH-17s were acquired for $20, restored, did not perform well by contemporary standards, and were turned over to me as an experimental upgrade platform. I have learned from working with them, and I trust that others will have, as well, blasphemy notwithstanding.... :yes:

 

[Paratima]

'Nuff said. If it twangs on your delicate sensibilities, look away. ara:

 

[Zilch]

Two Pioneers:

Anyone know anything about either of these?

They are in the BB6P database.

#1 = Vio, #2 = Cyn, DC250 = Blk

 

[Paratima]

Oh!
Never mind. Love them DC250's! :yes:
Updated schemo printed & hanging over workbench.
Parts list being updated - order will go out mañana.
Jig saw warming up.

 

[Zilch]

Love them DC250's! :yes:

BB6P says DC250 has ~3 dB of boom in 2-Pi alignment, i.e., one boundary, not unlike what the Bauhausler is experiencing with his E'Waved Advents. My nearfield measurements confirm that; they're 2-Pi also. It'll be fun to see what you measure when they're done.

My ducts are now 5" each, just 2" going through the baffle plus the elbows, which are now aimed up and inward. BB6P says I'm tuned to ~40 Hz with that; I'll measure to confirm, and then maybe stick the extensions back on the elbows, still aimed up this time, tho.

I'm playing them on stands, freespace, i.e., no boundaries reinforcing the bass, just room rise. They don't sound boomy to me, but I imagine they could be, if I moved them back to a wall. With an Fs of 25 Hz, DC250-8 can likely handle a lower tuning; BB6P says that'll get a couple of Hz lower F6, and knock down the peak by ~1 dB, all worth pursuing.

Yes, they'll rock the house -- 106.3 dB down to 32 Hz it says.... :yes:

 

[Paratima]

Cool. It'll take a couple of days for all the parts to get in, so maybe you'll come up with a "best" porting by then. Not afraid to play with that some, anyway. 1.5" ports, right?

I'm diverting everything from the Advents over to this, so I'll have to make/acquire new PCB's. Got the positive masks, so I should be able to make my own. I expect to copy Bauhausler's general plan for the board mounting & interconnects, L-pads, etc.

Copious note- and photo-taking will occur.