Re: Subwoofer crossover issue - Paradigm
Hey Tom,
I have a couple of suggestions you may wish to check out: Before I get to that, let me just say that I only know Paradigm to make good products and although the PDR-10 may not be the company's current flagship, I'm sure it's still a pretty decent unit. The same can be said for your Denon AVR. In other words, my presumption is that your challenge is NOT due to substandard audio gear!
There is some further info that may be helpful, but in the absence of that I shall rely on mere intuition.
If the sub has a phase/polarity adjustment, I suggest playing around with it. It may be an infinitely variable adjustment between 0 and 180 degrees say (typically a rotational knob), or some sort of 'click-stop' or toggle switch that adjusts the phase in fixed increments (like 0 OR 180 degrees). Your sub may be currently playing partially or fully out of phase with respect to your mains. If that is indeed the case, you shall surely observe attenuated mid and deep bass especially with music program material. The effect is normally more pronounced in the mid-bass but can carry over into the deep bass if your mains are capable of substantial deep (< 45 Hz) bass output and the high-pass Xover in the AVR is of low order (gentle slope). Note that when you calibrate the speaker levels of an HT system with pink noise and a sound level meter, you do so speaker by speaker which does not reveal the speaker interactions that shall occur when they all play together.
If your sub does not feature phase/polarity tweaking capability, try reversing the polarity of your mains by swapping + for - (red for black) on the speaker connections on the rear of your AVR. Do this VERY carefully with the AVR unplugged checking over all connections before firing everything up. Ensure there are no stray wire shunting strands etc. You may also take this opportunity to ensure that all your mains are actually in phase (you may wish to verify polarities on the speaker ends of the cables as well)!
NB: The reduction in dB when you turned the Xover on the sub down is 100% normal when calibrating a sub's level with pink noise. In turning the Xover down, one attenuates the upper part of the band and reduces the (upper) bass energy that emanates from the sub. Of course, it can also be possible that there is some gain/crossover interaction but I am assuming such is not taking place: Even so, gain/crossover interaction is typically a very minor issue and can be easily compensated for.
One more thing: If you can defeat or bypass the crossover in the sub, do it! In addition to the excessive attenuation caused by cascading crossovers, Analog/LCR filters are notorious for the group delay they introduce. Time alignment in audio reproduction is critical in obtaining accurate sound. If you want that kick-drum to exhibit a natural attack and decay with a nice tight/snappy texture, bypass the sub's Xover. Always remember that the low frequency sounds from the sub must mate with the upper harmonics/partials/overtones from the mains for faithful recreation of musical timbre. If you cannot defeat the sub's LP Xover, turn it up to its highest pass frequency (typically fully rotated in a clockwise direction - 150 Hz in your case).
I hope this helps. If not, we'll just have to try something else!
Keep well and enjoy your rig!
