JBL D-130s & Altec 511b horns...

[Zilch]

BEAUTIFUL! Those were quite a find.

Call a couple of your local furniture refinishers about stripping the grilles. One or more may still have a solvent "tank" to wash them like new for you at minimal cost.

I did that with a pair of Olympus fretwork grilles, and they came out spectacular(ly):

 

[Carl G]

I'm scraping up some money to get the needed test equipment. Not that I don't believe Zilch, but more because if I expereince it first hand I will understand it more. That and this kinda thing is of much interest to me. I wonder though :scratch2: , have the Altec drivers you measured been remagnatized?????? None of mine have, The 806A's have never been opened and the 808-8A have new Radian 1228 diaphragms in them. Neither setup sounded bad (actually pretty good) when used on the 511 with the A7 bass bin, but both are painful (literally) on the 811. I don't want it to be so, but I think the 800 series drivers from Altec are lacking :tears: . Still holding on to hope that it ain't so :sigh: .

I just want to echo Zilch's comments that the 800 series drivers should sound similar with both the 511 and 811 horns, at least on the top end - at least in my experience the various 800 series drivers I have tried sounded similar switched back and forth between 511 and 811 horns. The one caveat I suppose is that if the crossover is trying get anything much below 800 hz out of a 811/846A combo, I suppose that could cause the combo to sound bad. But, with everything set up properly, 811/806As can sound pretty nice. Just lacking on the very top end (and I prefer a tweeter up top anyway).

 

[macaltec]

I just want to echo Zilch's comments that the 800 series drivers should sound similar with both the 511 and 811 horns, at least on the top end - at least in my experience the various 800 series drivers I have tried sounded similar switched back and forth between 511 and 811 horns. The one caveat I suppose is that if the crossover is trying get anything much below 800 hz out of a 811/846A combo, I suppose that could cause the combo to sound bad. But, with everything set up properly, 811/806As can sound pretty nice. Just lacking on the very top end (and I prefer a tweeter up top anyway).

I understand, I found (in my application) that whatever I paired with the 811 caused me fatigue, whereas whatever I ran on the 511 was fine. The 511 is crossed at 800Hz and the 811 was tried from 800 to 2000Hz actively and 800Hz passively. It may have had more to do with its integration with the LF driver, I really dunno.

 

[ejfud]

Nice work Redboy! Those are going to look stunning when done. Almost a shame the horn will be covering the tops.

 

[Zilch]

Update:

Four 806A drivers now. Some GPA refurbished 802-8Gs on the way for comparison.

Second result adds in JBL LE85 driver, good to 14 kHz, apparently.

No, I don't have an agenda. I'm just clickin' buttons here..... :

 

[Redboy]

Got my crossovers today and have one barely working... shoddy wire, no solder on the joints. Pretty crummy job overall.

Now I'm running a single speaker off a crappy BPC receiver in the garage. I never was much able to judge the sound of mono. Seems I really need the stereo effect to understand what I'm hearing.

That and I've got a head cold and plugged up ears. :sigh:

So far, I'm underwhelmed. As I expected. Maybe tomorrow I can bring it inside and feed it some tube watts. That should improve things.

 

[Zilch]

So far, I'm underwhelmed.

We'll call that your "Baseline," then....

 

[macaltec]

No, I don't have an agenda. I'm just clickin' buttons here..... :

The truth is sometimes painful, especially to this Altec fan, but that doesn't make it any less true. I guess I have some nice midrange drivers.

 

[Zilch]

I guess I have some nice midrange drivers.

A sample of four is far from conclusive, of course, but I can't say it's looking real good, alas, at least not for un-refurbished drivers, which is what most everybody is listening to.

You're setting up to measure yourself, apparently, but you're welcome to send them out here for confirmation and addition to the database....

 

[macaltec]

You're setting up to measure yourself, apparently, but you're welcome to send them out here for confirmation and addition to the database....

Thanks, I doubt I'll get as far into it as you are but who knows. I'm a cheapskate, I won't even send them to GPA for a free remag with a diaphragm purchase. The cost of shipping just drives the price up to a point that seems ridiculous to me. I'll get more enjoyment from the test equipment. Of course I may end up getting rid of a bunch more speakers as a result of it too, the wife will like that :yes: .

 

[doucanoe]

Hey Nate, Sorry I haven't been around to talk much, I just started a new job on Monday and my dance card has been filled.

The cabs are sure looking great and I think everything will come around after you get settled in. It's hard to get a clear idea of what you are working with when you are trying to drive one speaker off one channel of a BPC SS receiver let alone trying to listen with a head cold.

Tubes my friend, tubes. I'm sure I will get a lot of flack from the Altec/SS guys for saying so but its just my opinion. If my options were limited to the SS amps I have owned or own I would probably sell my 291's and move in a different direction. I ask the question of tubes or SS to others here from time to time but never get a clear answer.

A couple of questions. Have you l-padded those 808's yet? Also, I assume that you have properly tuned, braced and damped the cabinet you are listening to? All of the above will make a difference I would imagine.

RC

 

[Redboy]

Yeah, my last post was pretty whiny... poor me.

RC, I do have the l-pad wired in. I'm aware that my testing conditions were far less than ideal. I was really just checking to see if I had things wired correctly, and I know I'll hear much better sound soon. :yes:

I'm with you on this one, though. Tubes are the way to go. I really don't like the sound of anything else these days. At least, not anything I own. I'm going to take that little Olson amp and a CD player out in the garage tomorrow. Or lug a couple of really big boxes in...

Oh yeah, I'm still looking for a 5" diameter tube to use for the new ports. Found out today that they don't make 5" PVC (I'm not a plumber!). Now I'm starting to look for things around the house that might work... oatmeal canister?!

Congrats on the new job!

 

[ejfud]

Jumbo craft tube from Uline or any other craft store should work.

 

[Redboy]

No port tubes installed yet, but I lugged these things inside today to run them off the Pilot 245-A. I listened to just one first, along with one of my Klipsch Forte's. There's definitely a chunk of HF missing when you hear the two side by side! However, the midrange from the 511B's seems much "bigger" to me. Maybe warmer, I don't know, but definitely different.

Once I got both speakers running together, I don't miss the high highs so much. I've got a lot more tweaking to do, and a lot more listening. Placement is no good yet and my ears are still plugged, but I'm hearing a lot more potential now!

I like where this is going... And it's a lot of fun!

 

[Zilch]

Tangerine:

http://audioheritage.org/vbulletin/showthread.php?p=160605#post160605

 

[Zilch]

Gettin' Close:

It's quite listenable "Out of the box."

But soooooo much better with compensation.

Gonna try adding one more notch to flatten ~3 kHz. :thmbsp:

[That's an important place.... :yes: ]

 

[Redboy]

Cool!

What effect will compensation have on sensitivity?

 

[GordonW]

Compare the 10KHz-20KHz levels to the 1KHz-3KHz levels on the plots of the uncompensated graph, to the graph of the compensated one. The loss in the 1-3KHz range, is the theoretical loss in efficiency, in an academic sense.

In real life, it MAY NOT be as drastic of an effective loss...

Regards,
Gordon.

 

[Zilch]

What effect will compensation have on sensitivity?

You can see on the voltage drive plot that it varies with frequency, using more at the low end, but the driver's playing too "hot" in the system there to begin with. Looking at the uncompensated frequency response: if I did nothing at 14 kHz and pulled 3 kHz down 10 dB (getting the rest of it right, of course, ) it'd play absolutely flat. I'm not taking it that far.

Also, be aware that the BMS driver has higher sensitivity than the Altecs, perhaps as much as 9 dB extra "headroom" to work with. In the end, if you still need an L-Pad to balance with the woofer, you have "enough" sensitivity.

 

[GordonW]

In the end, if you still need an L-Pad to balance with the woofer, you have "enough."

Yep. That's how it's turning out with my Radian coax drivers. The horn is like 10 dB louder than the woofer, but drops 8 dB over the range from 1KHz to 20KHz. So, I compensate 8 dB, and pad 2 dB... no problem!

Regards,
Gordon.