Originally Posted by LTD02
"Why do you ask?"
i was kind of wondering if the peak in some the recently measured subs behaves in the time domain similarly to the way a room mode does or not.
That's what I thought you were getting at.
First, you can't eliminate a room mode with EQ. You pull down the peak with EQ, but you don't eliminate the stored energy. That's why you still see it in a waterfall graph.
A notch in the signal to the subs naked FR is a different situation. The peak from high inductance is not stored energy. It's what's left after the roll off above it.
I have disagreed with Seaton's 'fingerprint' theory simply because I've never seen any evidence of it. He says it rears its head when you 'push the sub to its limits', but any number of bad things (and/or changes caused by design, such as limiting) can happen anywhere in the chain when you do something like that.
In any case, I've heard dozens of subs in my room over the past 20 years. If there was any sort of ringing from the SSD-based subs, I would have heard it, rejected the design and not have ever suggested the SSDs to anyone.
On the contrary, other than lacking a few dBSPL below 20 Hz compared to other systems I've built using longer throw, lower Fs drivers, the system kicks serious a$$.
The Tumult MKI (and several other overhung, long throw, low Fs drivers I've used) rolled off -8dB from 50-100 Hz and I never experienced ringing after L/T signal shaping. (Instead of a notch, I used the L/T to treat the peak as a high Q sub, which gives a similar end result, but the price is that the L/T extends to above 200 Hz).
When most people say a sub is 'tight', they're usually referring to the fact that there is no low end. When I refer to a system as sounding 'tight', I'm invariably referring to the fact that there's no audible ringing because every system I design is flat to 4 Hz in my room.
I've read various opinions about high Q ringing and have since dismissed them as irrelevant to the 'after' notch with L/T response and its performance. When my systems are pushed to their limits, it's always below 20 Hz where the heaviest L/T boost is. Where the notch is, the system is doing the back stroke. Otherwise, you've designed a seriously flawed system.