power response curve for Altec 288-8K

[Horatio]

I have recently acquired a pair of Altec 288-8K drivers, and have been struggling to find a response curve for this driver. Ideally, what I am looking for is power response on a tube, so that it is possible to see the driver's upper roll off point.

Anyone have this or know where it might be found?

Thanks!

[sunnysal]

which model 288? B, D, G, K or L?

http://www.greatplainsaudio.com has a good specs library as does http://www.lansingheritage.org/html/altec/altec.htm

regards, Tony

[sunnysal]

forgot to mention the only response curve I have ever seen for the 288 but it is for the G model:

http://alteclansingunofficial.nlenet.net/publications/techletters/TL_231.pdf

tony

[Horatio]

Thanks- another lister recommended to look at a 299A datasheet, too, which shows essentially similar behavior, except that the 288 has better response above about 9 Khz or so. My understanding is that the 288-8K has even better high end behavior than the earlier 288 models, although the audiophile contingent seems to value the 'g' series more. I have not heard the 'g' vs 'k', so I don't know.

I have mounted these to a pair of EV HR6040 horns, and so I am looking to see how to equalize the drivers for the CD character of these horns.

When I first listened to these drivers with the same EQ I used with EV DH1012's, I was initially disappointed in the 288's- the lower mid range seemed lost, although the high end was there, and silkier than I recall the DH1012's having.

Then, I looked at a response curve (unequalized) that was obtained here: http://www.triodefestival.net/index.php?page=etf-2010-shootout At the bottom of this page is a pdf of the results of this 'shootout', and a pretty cool summary of how the 288+HR6040A measured.

This shows what is listed as a 288 on an HR6040A, and the bottom end of that response clearly needs to be equalized. This seems to match my listening tests of the 288 I have on the earlier model of the HR6040: top end sound's good, but the bottom seems missing or lost. The measurements also show that the 288 doesn't need much CD (top end) equalization, if at all, on this horn, but it does need some bottom end tuning.

It's funny that the DH1012 doesn't sound like that at all on this horn. But then, this driver was probably developed in conjunction with the HR series.

Thanks!

[sunnysal]

the EV DH1012 is not a bad midrange driver and mates well with the horn (though depending on your room the 90 degree horn might have been a better choice), why are you interested in using the altec? what tweeter are you planning to use? you´ll want to cross over at about 6k with the DH1012 regards, tony

[Horatio]

Tony:

I agree, the DH1012 is a very nice driver. I went to the Altec to get more top end, so that I did not have to go back to a three-way configuration. The 288 can take me high enough that I don't really have a need for a tweeter (not sure I am hearing that high up beyond the 288's any longer, anyway!).

I have a pair of HR9040A's, and I actually used those atop the Klipsch bass horns for a time, but they are way too large to accomodate long term. The HR6040's fit, width wise on the Khorn bottoms, and while they make the overall stack taller, they permit a true 2-way design, and give very stable polar behavior. This package gives a liveable size envelope, and is more, shall we say, wife-compatible. I have had custom cabinetry done to integrate all this, and am pleased with the results. With a decent equalization and crossover setup (all active) this combo is really quite impressive in my opinion.

I am keeping the HR9040A's, though, and using those on top of a pair of University Classic bass horns I have built. They fit nicely on those cabinents, and I will use the DH1012's to drive them. What to do about tweeters, here? Haven't sorted it yet, but I have a pair of Eminence APT's that seem pretty decent. This setup will get the active treatment, too.

-M

[sunnysal]

ok, now I get it. yeah the altecs will do a better job on the top end. unfortunately my hearing forces me to still use tweeters, lol. for tweeters, the JBL 2404H is a nice unit (doesnt go into the stratosphere in terms of upper range, 18-19khz? nor is the price to high...). sounds like you have some nice systems there. regards, tony

[gibber]

Just stumble overr this thread, @Horatio & rgd the ETF.10 shootout,

the meas taken by JMLC at the time were erroneously marked. The driver used was of own composition, mating Altec290 core with 288C diaphragm. In essence, a 288-8G. I took, perhaps unusually, a second horn/driver combo into that 2010 shootout with JBL2353+288-8K and perhaps caused Jean Marie's (may he rest in peace) mix-up of the comp driver names. Pretty evident in the photos the Melaudia / French ETF team took and published.

 

EV's HRx040 and HRx040A series differ significantly in lower mid freq response, see exchange on their history in AudioKarma between AK member abez0 and myself. Those posts were commented on by former EV staff elsewhere and provided here on this forum pointing to the possibility the changes were in fact mainly made due to easier manufacture (this was my initial guess, but the "A" series advantages then led me to believe otherwise).

Positive (mid/treble) and negative (lower cutoff) side effects of changing the HR series' initial expansion were maybe overlooked at launch as the majority of the horn bell, the parts facing the listener, stayed unchanged in expansion/shape. My (unconfirmed) guess is that when launching the "A" series, these went out from EV with data sheets previously compiled by Don Keele and actually show the non-"A" series radiation pattern details. Can some light on this be shed by someone more knowledgeable here, maybe?

Edited March 6, 2018 by gibber
Added 2nd paragraph with EV HR-series hints and unconfirmed assumption