Use a sub with your hi-fi system?

Great information here everyone. I'm happy to learn that sub use isn't completely out of the question and still exercised by many. Thanks.

 

Low frequency bass is an important part of the live performance whether acoustic or electric. I enjoy it when listening to recorded music too. The sustained notes of an acoustic bass, the impact and harmonics of orchestral tympani drums, the punch from a kick drum, the deep notes of a bass pedal.
Right now my main speakers do a great job of reproducing these frequencies. In another system they don't (example- bookshelf speakers) and I use a sub in that one. Takes some experimenting with level, phase and position but once dialed in it sounds integrated and natural. I've found that it is usually best to invert the phase of the sub.

 

Took some time and effort, but I use a sealed sub in my hybrid rig for both HT and 2-channel via int amp w/ ht bypass.

When in HT mode, bass management is via the AVR in the digital domain with the appropriate xover frequency controlled from the AVR.

When in 2-channel music mode - its all analog baby with the sub. Mains get the full freq and the sub's low pass set to mesh with the -3db down response of the mains. Got it dialed in nicely.

 

yes as my Heresys roll off at 60htz. There's only one place in my living room where the SVS can reside and that's adjacent to the left speaker. Incredibly low WAF as well.

 

I use two B&W 608 powered subs with my pair of Nautilus 805 speakers ( solid state amp and preamp ). I use a pair of restored KLH Model 5's with my tube system so no sub is required.

 

Bass management box for 2 channel. (Home Theatre too)

http://www.dspeaker.com/en/products/anti-mode-8033.shtml

The Dspeaker eliminates nodes quite nicely. After living with one for a few years, I wouldn't be without.

I only use DSP for the sub.

 

Can we talk about that a little? I've never been clear on how to set that, so I keep it at zero degrees.

 

Pretty much how I have my stereo music/HT combi system set up.

 

Sure. Basically when you reverse the phase of the sub, you are avoiding offensive peaks in frequencies where the sub and main drivers overlap. These are usually really nasty and part of the reason subs have gotten a bad deal among audiophiles and a good rep among the bass heads in home and car audio. They love the peaks. I do not.
This has been confirmed in my car and home systems using RTA software as well as the ear test.
The other advantage is that the sub and main drivers do not compete at the same pressure pulse. In a car, for example, the pressure pulse of a good sub is enough to flex your window glass. It also wants to "push in" the woofers in your main speakers at the same time they are trying to pulse out.
This pressure competition causes distortion and cancellations in the midbass- which further exacerbates the peaks in the lower bass. If the sub phase is reversed, the negative pulse of the sub tends to "suck out" the positive pulse of the midwoofer, not compete with it.

 

The phase setting depends on room, and will be affected by the distances to boundries, distance variance between sub mains and listener, main speaker phase angle at the sub crossover point, and others random anomalies. The best thing you can do is measure. Second best, have a sub with variable phase not just a 0/180 switch. My sub has a 0/180 switch plus a variable knob to adjust from 0-180 so it can basically go from 0-360 degrees of phase in one degree steps.

The REW software already mentioned above will overlay phase angle onto the frequency response charts. Crazy phase angles will create peaks and nulls in your frequency response.

 

Hell Yes and nobody knows it's on.

 

Very interesting info, thanks. I had assumed that the Phase adjustment was dependent on the direction of the sub relative to the mains or something like that.

Since I do not have the capability (or knowledge) to do any measurements, and given that my room is 9' x 12', the mains and sub are facing the same direction, and the listening position is about 5' or 6' from the mains, would you typically advise adjusting the phase to 0, 180 or somewhere in between? I certainly will play around with that this evening!

 

No with no need to.

 

It helps me to try to visualize the affect.

Pick one frequency. A 50hz wave is 22.5' long. 10 degres of phase adjustment equates to 7.5 inches (22.5/360*10*12(inches)). So for every 7.5 inches that you move the sub you are changing the phase angle by 10 degrees at 50hz.

Throw in that applying a filter (crossover network) shifts the phase and multiply that by two (mains and sub) and you have varying phases to deal with when integrating the crossover point between the mains and sub. Might be able to multiply by three or four if you throw in a port system or two.

For example if you are trying to cross at 50hz, the mains might be at 20 degrees, and the sub might be at -20 degrees. Somehow you will need to adjust something to try to line them up or the results will be less than ideal. The options to adjust are placement by changing the distance, a phase adjuster, or most likely, a combination of both.

The problem is, how do you know the phase angle in room of your mains and sub without measuring? As stated before, just throwing a sub into a room and setting the volume knob will rarely result in a balanced integration. So the answer to the question, how to set the phase, is room, speaker, crossover setting, listining position, and sub dependant. You have to experiment to find the right combination for your system.

 

Could you elaborate as to why this not your preference?

 

I own one sub and have only used it for HT. I've always found Earl Geddes theories on multiple subs to be very interesting, but have never heard or implemented that kind of a setup.

 

I think my head just exploded.

 

Is it?

 

Sounds like you could use your own personal FAQ.

 

Or something else.

 

Yes. The placement for the best bass reproduction is nowhere near the ideal placement for everything else audiophiles want. It's simple acoustics. No voodoo. Go without to your own detriment.

 

Nope....I use big speakers in big boxes so I don't need a subwoofer.