Subs or no Subs?


#1

After listening to Paul’s Ohms law podcast, “Should speakers be rolled off?”, I’m a little confused as to his message.

In summary, he is saying, if you have a well designed full range loudspeaker with full range woofers, do not
mess with the speaker design by rolling off the lowest end with a crossover to external subs.

However, he is, without reservation, also recommending subwoofers to any loudspeaker system.

Don’t you have to set a crossover and roll off the loudspeakers whenever you integrate external subs?

I have Avantgarde Duo’s with dual amplified subwoofers down to 20 Hz. I have added external subs crossed over at 40 Hz. The sound is natural with no indication that the subs are there (that is until they are removed). I find the external subs add some extra weight and palpability that the speaker subs don’t supply.

So my question is: Is there a difference in my crossover setup to what Paul is recommending against?

Just curious…


#2

I think what Paul advocates is allowing the full-range to play to their natural “roll-off” and adjusting the high frequency & roll-off of the sub-woofer to best match (or support if you wish) the main speakers.
Others say using an electronic crossover (DSP) and custom filters to control both is the best way to go.
In the end you want to avoid as much as possible an unnatural boost to the low frequencies by having too much overlap from both speakers. Your ears should be able to tell you but frequency sweeps and analysis software like REW will help you confirm it.
I think your AG’s have filters/slopes in the subwoofer to match the horns. I assume you have then adjusted the additional subs own high frequency and filters to best match the rest of the system.
I like AGs- look and sound great.


#3

So, I think I understand that the message is not to crossover the speaker woofer too high. That is, set the subs to meet near the speakers roll off point, thereby letting the speaker function full range as it was designed?

If the AG’s are rated down to 20Hz, are they in reality starting to roll off around 30Hz?

So perhaps this is why I’ve found good results setting the subs crossover at 30 or 40Hz.


#4

I prefer allowing the mains to roll off naturally, and limit the subs. Overlapping the xover can be beneficial as well, as you’ve done and found. You’ve got it if you don’t hear the subs until they are removed.

I have also found REW and UMIK mic very helpful in dialing in the phase settings. I was able to smooth out a couple dips and peaks that I never was able to by ear.

Experimentation is under emphasized in this hobby, in my opinion. So much to be gained for so little effort and no spend. The number of accessible, changeable variables can be overwhelming.