Asheville, North Carolina ‘s Home Theater and Audio specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

You probably have it wrong

I remember the first time I managed to find myself in close proximity to a pipe organ. Terri and I had spent the night at Denver’s Brown Palace hotel and after breakfast we wandered a bit. Across the street was a cool looking old church with obvious architectural delights adorning its sides. As it was on a Thursday, we went inside just to poke around. From upstairs we could hear the sound of a pipe organ. Quietly we made our way upstairs to find a single person sitting in front of this massive instrument. It appeared to be preparing to swallow her whole. It reminded me of Phantom of the Opera.

She turned upon our entrance and invited us to grab front row seats if we didn’t mind listening to her practice. What a treat! An amazing instrument, the organ. On her break I asked her to play the pedals, low notes in particular. I was stunned at how those notes took over the room. The church was made from stone, my pants from cloth. The stone didn’t rattle but the cloth in my pants did, so powerful the low notes of this gargantuan instrument. I closed my eyes trying to imagine how this would reproduce in a small room.

From the messages I’ve received I feel rather confident your home systems aren’t reproducing organ notes as I heard them in church that morning. On the IRS or the Betas, those notes, reproduced in a small to medium room, take the room over; as they should. Does yours? Do you feel the organ in your belly and smile at its massive power when played in your room?

Now I understand not all of you listen to organ music. Perhaps none of you do. But there’s much in the subterraneum areas you’re missing if you don’t have the sub right, and an organ is a great test piece to get it right.

Why not run a little test to see where you are in terms of low bass.
I have two suggestions: Reference Recording’s Rutter’s Requiem and Daft Punks’ Random Access Memories. Yeah, I know they are so similar in content …

Use the Requiem to see just where you are with well recorded pipe organ music. Don’t worry that you don’t listen or like the music. My favorite is track 7 Requiem: Pie Jesu. There’s some very deep organ notes that take over the room. There’s also amazing spread on the chorus as the men first come in, followed by the ladies. This whole track should be completely divorced from your speakers, floating in a perfect soundstage behind the speakers.

And here’s something critical: when the organ comes in it should have no impact on the singers, for without a subwoofer, you’ll hear intermodulation distortion of the chorus when (and if) the organ takes over the room. Most full range speakers don’t reproduce the organ so it takes over the room and, if they do, it’s likely the chorus gets wobbly and muddled. You really can’t have it both ways without a 4-way system. So, rule of thumb – if a single speaker CAN produce bass like it’s real, it’s likely also affecting the midbass and midrange with IM. If it doesn’t have the IM problem, it’s likely not reproducing the organ notes properly.

Once you have this right, and I’ll bet money you don’t with a single pair of speakers, then go to the Daft Punk song. I like track 4, Within. The other tracks are ok dance music, if you like that, but track 4′s a gem. If your subs are working properly, there’s an extraordinary bass note that permeates the room perfectly when the intro’s done. On a full range system you probably have no idea what this note actually sound like.

Get the bass right. It, along with AC power, is the bedrock/foundation of our music systems.

Tomorrow, we move to another subject.

Asheville, North Carolina ‘s Home Theater and Audio specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

The better it works …

If you think about it, the greater the impact something has in your system, the more important its role in your system. That might seem obvious, and it is, but it’s important to review again.

An example would be subwoofers. If you add a sub to your system and that system’s transformed, I would suggest that the level of transformation indicates the degree of bass deficiency of your main speakers: the more it helped, the more you needed it.

Why’s this important? I think it helps debunk the myth of ‘full range loudspeakers’ some manufacturers have been trying to convince us of for years. I can’t tell you the number of times I’ve visited people who proudly show off their ‘full range’ home audio system to me that I have to disappoint with the news they’re missing the bottom octave. Sure, it sounds like it goes low, but until you hear it actually go low, there’s no point of reference to make a judgment; unless you know intimately the sound of, say, a pipe organ.

But now onto the question of one vs. two subs. In yesterday’s post I suggested a formula I use is small room, small speakers = one sub. Large room, large speakers = two subs.

In a decent sized room with ‘full range’ loudspeakers, a subwoofer on each side, fed separate left and right signals from the preamp or DAC, works well because of the room’s larger size. Most of the directional cues for bass tend to be higher frequencies that come from the main speakers so having it on one side or the other has minimal impact on the soundstage directionality. But keeping the low frequency pressure even in a large room can be aided with the addition of the second subwoofer.

Perhaps the biggest trick with any configuration of a subwoofer is keeping the crossover low pass filter as low as you can manage. It should be high enough to fill in the midbass areas of double bass, cello and big brass (if they need it), yet not so high that it draws attention to itself in the room.

Make sure you never hear the sub – that all bass seems to come from the main speakers – and when an organist places her foot on the 16Hz pedal, that ought to rattle you and everything in the room. Just like you were there.