My IB Sub

[jeffbridges]

Chrisbee - can you point me to a thread where you uncover what was holding you back? I read some posts a while back where you were not pleased with your IB, now I read some where you are thrilled - but I haven't seen much in between. Can you pls explain? Jeff

[Chrisbee]

Jeff

I'm not sure I posted to a particular thread either here or on the The IB Cult. It was probably just improvements I mentioned in passing.

The problem was really simple. My stereo preamp gives out about 300mA. A pro amp (like the EP2500) needs 1.2Volts.

The EP2500 has two attentuators which I (and many others) thought were volume controls. They're not. These two knobs reduce the input independantly to each channel. After 40 years of the hifi habit I was simply afraid to wind these controls up fully. It's just not done with stereo volume controls.

So I had nowhere near enough input juice to excite the EP2500 to decent levels of output. Even in bridged mode I wasn't getting dynamics or much visible cone movement. The SQ was fine but the IB had no real guts.

I needed to increase the input to the EP2500 by 6-9dB. This was easily accomplished by screwing up the input gain on my Behringer CX2310 active crossover and winding up the twin controls on the EP2500. The bass channels were increased to +6dB and the speakers channels backed off to avoid overloading the speaker's stereo power amp.

Finally (and quite by accident) I discovered my DVDP was set to DRC (dynamic compression) and quickly fixed that problem.

Now I had frightening bass. It went well beyond my wildest dreams. In fact it's a bit of a nightmare once the cones start moving seriously. I'm really afraid I'll hit bottom on the 4 x IB15s limited Xmax as the house creaks and doors rattle in their frames.

Now I discover I'm not even getting my LFE and Centre channel bass redirected to my front main channels. (which is how my IB is driven) So finally I have to buy myself an AV receiver to get serious bass perfomance? I'll probably need 8 drivers to cope and a lot more nerve to survive!

If only AE hadn't collapsed and air freight didn't more than double the price of drivers for IB fans in Europe. I would probably have 8 x 15" drivers by now. Or at least 4 x 18" drivers with serious Xmax. I don't want louder bass and can't fault the superb SQ. I just want better dynamics with less cone movement. So I can relax and enjoy films without worrying about hitting the end stops. I have never have heard anything at all odd from the IB but I do worry about suddenly reaching the driver limits without warning.

[toecheese]

I had to use the DSP1124 to boost the signal to what I needed on the EP2500. Actually, that's how I got to this site- getting info on the REW. The guide is very good and tells you how to program the DSP to give the output needed.