Infinite Baffle Sub

[bri1270]

Well, I received and installed 2 x Avalanche 18's yesterday. It took me about 1/2 hour to install, and wire them up since I had done all of the setup work before hand. I have them wired for a 4ohm load being driven by an Alto Macro 1400 (450 w/channel).

First the sub - I was immediately impressed. I won't go through all of the typical buzz words - detailed - tight blah blah blah. It kicks serious A$$, and that's that. I recalibrated my system, and I deliberately ran the sub hot, and I mean all the way hot, and it still sounded awesome. It was a bit much, but I wanted to see what it would do. Basically, everything was vibrating, including my seat which is about 11 feet from the installation. The dog took off wimpering. There was no damage to the house. As a matter of fact, I was concerned about my installation because the IB is about a foot to the right of the TV, so I figured my screen would be shaking and vibrating all over the place, but it didn't. As a matter of fact, it vibrated less than whith my Earthquake sub. Music sounds great! I haven't had a chance to watch a whole movie with a lot of LFE, but I'm sure it's going to be good. I did throw in Finding Nemo for the Darla tapping on the glass scene, and it was freakin' awesome!

Now for the Amp - it's definitely built well, even though it's manufactured in China. I opened it up and it's pretty much the same as any other amp. Fan noise is a little more than I had originally thought, but it can't be any worse than the other pro amps, so the typical resistor mod should work. For me it's not an issue at all since all of my amps are in a "control room" behind my HT. It's pretty versatile, handles up to a 2ohm load, has clip limiter, 30Hz cutoff (switchable), and runs stereo, parallel, or bridged (also switchable). Binding posts are sturdy, offers XLR and TRS connections, as well as speakon outs. Gains with detents, and signal/clipping lights on the front panel. Signal lights are nice, they show how strong the incoming signal is. For example with the sub, you can see them blink when the amp receives a low frequency signal from my receiver.
I don't have the equipment to measure the amps actual output, but it seems to be good. I asked the guys at DirectProaudio.com, and they said it is what's spec'd. They also said it's their most popular amp. They rent them out locally, and they said they seem to take a good beating and keep on working.

Here's my uncorrected response:


Just for the hell of it, I took some more measurements:

10hz - 64dbC
11hz - 71dbC
12hz - 74dbC
13hz - 76dbC

My system is calibrated to 75dbC, with the sub running a little hot at 80dbC. My measurements were done at -20 on the pre.

At -10 I got 80dbC at 10hz

[curtis]

Very cool!

How is it from 20-80hz? Can you do an FR curve? Do you plan on getting a BFD?

[bikeman]

Very cool!

How is it from 20-80hz? Can you do an FR curve? Do you plan on getting a BFD?

Very cool indeed. I'm interested in the same questions Curtis asked. I'm also jealous.

David

[bri1270]

Well, here are some pics. I can't figure out how to get the curve to show up, because it's not a jpeg or a gif. So here are the numbers
Freq dbC
14 77
16 79
18 79
20 79
22 84
25 91
28 93
31.5 95
36 95
40 93
45 91
50 88
63 80
71 82
80 76
89 76
100 71
111 70
125 69


Yep, I have a BFD, and it looks like I am going to need it. You should see the dip I have at nearfiled. I go from 105 dbC at 50hz to 79dbC at 45hz. From 125 to 50 is pretty flat and from 45 to 14 is almost dead flat. All the conditions were the same as described previously.

You can also see my Ascends in the wall.

Okay, pics aren't working because they're too big. You can see one here :

http://www.avsforum.com/avs-vb/showthread.php?t=557868

I'll have to see if I can resize tomorrow.