Will this work to test an Altec 288-8K CD?

steve71

Member
2007-11-12 6:01 pm
I have an Altec 288-16k CD and 288-8k CD that I purchased off of CL today. I'd like to test them out and I was wondering if I could cross them at 200hz at low to med volume via my receiver to verify they are in good working order?


If this sounds like a really dumb idea :D, can anyone point me towards a software based HP filter for my PC so I can roll off anything going to the receiver 400hz? Once again this is just to test the compression drivers, which have Mantaray horns attached.

Cheers

Steve
 

steve71

Member
2007-11-12 6:01 pm
Thanks for the responses guys. I ended up downloading a bit of software that could apply a HP filter to a mp3 file.

I slowly worked my way down to 250hz with no trouble, so I decided to cross them over at 200hz via my Receiver. That way I could use my subs to get a better impression of the sound.

To my surprise they actually sound OK like this, even though the CD impedances do not match nor do the horns :xeye:.

Anyway this is a great opportunity for me to play around and see if horns are my cup of tea.

I'm getting a bit of shout and ringing on some recordings, but I guess that the MR64 and MR92 horns :confused: Anyway that is the subject of another post....
 
Hi Steve,

I own the 288C's that came as 24 ohm. I sent them down to Great Plains Audio and had new 8 ohm diaphragms installed and had them re-magged, so the option is there if you want two drivers the same. Mine are hooked up to the big horns, OK down to 300 hz but I'm afraid that's too low for my liking. When I get them up and running, I think 500 hz will be the lowest I will consider.

Good score, what did you pay for them and the horns included?

Any pics?
 

steve71

Member
2007-11-12 6:01 pm
Hey Cal, I think I've seen a pic of your speakers setup outside your garage. Looked like something from a rock concert :cool:

Thanks for the tip on Great Plains. I actually called them yesterday and talked about swapping the diaphragms so I'd have two the same. Bill (IIRC) suggest I test out the drivers in case one wasn't working.. better to replace the broken one lol! Right now I'm running the 16ohm driver about 5db hotter and that seems be working well enough for me to get an impression of the sound.

I was really lucky and got the whole shibang for $50. They came out of a Baptist Church, so naturally I had to play "Sympathy for the Devil" to christen them in their new home. I'll post up some pics tomorrow.

:D
 

steve71

Member
2007-11-12 6:01 pm
panomaniac said:
Why not just put a cap on them to test? Simple enough.

The main reason is that I don't have any caps laying around and it's easier to download a bit of free ware than to drive to radio shack. :) Yes I'm lazy!

I also really wanted to be able to use them with my subs so I could get an impression of the horns to see if that was something I should pursue. I've been entertaining the idea of selling my B&W 801 sII to fund a DIY horn project. I've never listened to consumer horns and I've hated the horns I've heard at concerts. However I keep reading such great things about horns...

So the opportunity to knock together a crude horn speaker using my subs and receivers crossover has been invaluable. Now I can decide for myself if it's worth selling the 801's and I only had to invest $50 in the test project.

Strangely enough they don't sound half bad on the the right recording. Just running a frequency sweep with RoomEQwizard I can hear they are down about 6db (guessing) from 10-15kHz and there's no output above that. Output seems fine around the 200hz crossover point. No doubt crossing the 288's at 200hz causes all sorts of issues, but that is as high as my receiver goes.
 

steve71

Member
2007-11-12 6:01 pm
Cal Weldon said:

I guess one could say that at $50 from the church, they were this close (putting finger very close together) to being a gift from God. :clown:

Anyway here they are. Far from optimal placement.. more like a mono setup, but since the subs are running mono crossed over at 200hz I wouldn't get much stereo separation anyway. I'm primarily interested in getting a feel for the dynamics and transients, so it's all good.

Subs are two VMPS Larger's powered by two crown XLS 402d's.
 

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