Subs

In yesterday’s post I mentioned I added a single sub to the setup in Music Room 2 and got great results.  Several of you asked me why I didn’t add two, which is always my stand on subs, and where I got the sub.  I wanted to also touch on how I connected the subwoofer as well.

Indeed, whenever possible, two subs are better than one – but not necessary.  The advantage of a separate left and right sub is primarily in the setup of the room – one on each side makes placement of the sub actually easier as it takes over the room better at those lower frequencies.  Further, if you need to run the sub at frequencies higher than 80Hz (perhaps you have a pair of bookshelf speakers) or would prefer to have a gentle rolloff on the subs low pass filter (determines how high the sub goes) then the sound of that subwoofer can start to become a bit directional.

So my rule of thumb regarding subwoofers is to keep the subwoofer from going too high, hopefully never higher than 80Hz, keep the slope of the low pass filter to no less than 12dB/octave and adjust the sub level so it never stands out by itself; instead it helps the main speakers sound as if they have deep bass.

If you’re using a single sub, never place it between the two main speakers, always place it either to the left or the right of the mains and NEVER rolloff the bottom of the main speakers.  By this I mean many subwoofers have an in and an out set of connectors where the output connectors on the subwoofer are called a high pass filter.  This filter is used to make sure the main speakers don’t have to work as hard going down in the bass area – and allows the subwoofer to do the work instead.  This notion of rolling off the main speaker’s bass response was popular a few years ago in home theater circles, but trust me, it’s not a good sounding plan.  Let your main speakers do what they were designed to do and use the subwoofer to fill in what they don’t – and almost no full range loudspeaker gets down to 18Hz with any authority so you pretty much need a sub.

With respect to connecting the sub, in many cases I prefer to use the subs high level inputs and tap off of the main power amplifier’s output.  This method doesn’t use any of the main power amp’s wattage – just its output signal – the sub’s power amp doing all the work.  What it does accomplish is two things: removes the extra cable load off of the preamp or DAC feeding the sub and helps maintain the sonic characteristics of the main amp giving you a more seamless blend.

The subwoofer I am auditioning is a new product from a Colorado based company that is extraordinary, but they did not include a high level input.  I had to make my own and tomorrow I’ll tell you how.

Paul McGowan – PS Audio, Intl.

Finishing touches

I was up late two nights ago, as you may have read, dialing in the speakers in Music Room 2.  The speakers are a pair of Thiel 2-ways, using their coaxial driver arrangement.  These are simple, well designed loudspeakers which are a perfect contrast to the giant Infinity IRS in Music Room One.

Some of you may remember I explained that there are really only two perfect means of building a loudspeaker system: an infinitely small point source and an infinitely large line source.  The IRS is as close as anyone’s gotten (IMHO) to a practical line source and the Thiels are a pretty excellent point source – and while not infinitely small – their 5.5″ main driver and tweeter are about as close as you can practically get and still have reasonable frequency response.

To finish the installation in Music Room 2 I had to both augment the bass response and add a couple of corner traps.  Here’s a picture of what we wound up with.

Music Room 2 Finishing touches

Note the three RPG diffusers between the two loudspeakers as well as the DAAD corner bass trap.  Also note behind the right loudspeaker the hint of a subwoofer.

The Thiels are quite bass shy and would never qualify as a full range loudspeaker under any conditions I am aware of.  But that’s ok as I set these up over the last few days to have great imaging, a solid center fill, wonderful tonality and all that’s lacking is bass from 80Hz on down to 18Hz.

You might wonder what I used for a subwoofer and I can tell you that this is always a hard choice.  While there are many great subs around, few have met my criteria for subwoofers as I am (admittedly) a sub-snob.  When I add a subwoofer to the system In never want to hear it – ever.

Friend Neil Rosenblum from Florida recently sent me a slew of CD’s to audition (thanks Neil!!) and I immediately put Brian Bromberg’s great CD “Wood” on to test.  Track one of the CD starts out with Bromberg playing the bass solo and you’d swear he was in the room.  I brought several PS’ers into the listening room, played the track and asked where the bass player was “He sounds like he’s in those wooden things (the RPG’s)”.  Turn off the sub and everyone’s jaw dropped – it now sounded like a toy bass.

If you can keep the frequency of the sub low enough and DO NOT roll off the main loudspeakers, you can achieve amazing results – but you need a great subwoofer.

I have discovered an amazing subwoofer, built here in Colorado that I am testing out.  Wow.  I’ll tell you about it later – but this sub isn’t going anywhere.

Here’s another view of the room.

Music Room 2B Finishing touches

Now that the system is up and running and tweaked in, powered by nothing more than a 100 watt per channel PS A100, I put on another CD that was suggested by a reader, Madonna’s Immaculate Collection, track 8 and cranked it up.  The sound is more than wall to wall and it’s as if the little Thiels can reach down into the depths of the synth bass and go forever.

Lastly, if you look at the equipment rack you’ll note an empty space where CD’s have collected – that’s where a new turntable is going to be installed soon.  This means we now have two fully qualified music rooms we can use to audition just about anything we manufacture or when someone comes by to try their equipment on.  If you’re in the area, I encourage you to drop on by.

Tomorrow I’ll cover how we connected the subs.


Paul McGowan – PS Audio, Intl.