Do LP's have stereo bass? a subwoofer issue...

gooberdude · « **on:** 8 Feb 2007, 05:53 pm »

i'm all smiles after acquiring a Hsu sub and getting it tuned & positioned properly...deep bass is a lot of fun now that its works seamlessly (and musically) with my main stereo. aa

i'd like to purchase a 2nd matching sub to experience stereo bass, but is this a good idea considering my main source is vinyl?

while searching the forums about this topic, a few posters state that commercial CD's have summed bass below 60hz or so. I'm just wondering if LP's are different in this regard...if they have stereo bass all the way down or not (in general).

the sub was a monster until i engaged the phono pre's Rumble filter and mounted the Stf-1 it on top of nice brass footers and a spiked maple speaker plinth.

matt

woodsyi · « **Reply #1 on:** 8 Feb 2007, 06:10 pm »

As far as I know, stereo LPs have 2 channels of separate signals including bass. Mono LPs have two identical signals including bass split to 2 channels.

Russtafarian · « **Reply #2 on:** 8 Feb 2007, 06:12 pm »

I'm pretty sure bass is summed to mono below 50hz when the records are mastered. I think this is part of the RIAA equalization curve.

lazydays · « **Reply #3 on:** 8 Feb 2007, 06:32 pm »

Quote from: Russtafarian on 8 Feb 2007, 06:12 pm

I'm pretty sure bass is summed to mono below 50hz when the records are mastered. I think this is part of the RIAA equalization curve.

read the samething in several magazines thru the years.
gary

Russell Dawkins · « **Reply #4 on:** 8 Feb 2007, 07:21 pm »

vinyl records vary in the bass characteristics, i.e., the frequency of turnover and degree of mono-ization of the the bass, as part of the artistic judgement the vinyl mastering engineer is making. Some records have very stereo bass.

With CDs there is'nt so much need for mono bass. The main reason this is done is to prevent the playback stylus from being thrown out of the groove by a heavy non-mono bass transient.

The mono component of the signal results in horizontal movement of the stylus where the stereo component gives a vertical movement.

When the mono button is selected on playback, you eliminate the vertical component from the stylus, which often includes rumble artifacts. That's one reason that it is best to do that whenever possible (as in playback of mono records!).

I am off skiing for two days, so if I don't answer responses I'm not being rude - just not checking in.

TheChairGuy · « **Reply #5 on:** 8 Feb 2007, 08:14 pm »

I didn't know any of this - good stuff, guys, thanks

Psychicanimal · « **Reply #6 on:** 8 Feb 2007, 08:22 pm »

Stereo bass is for real & very important.

gooberdude · « **Reply #7 on:** 8 Feb 2007, 08:24 pm »

i posted the same question at the Vinyl Asylum and received the same responses....essentially the stylus would have a tough time with stereo bass under 50hz or so.

this saves me some $, thanks so much guys!

A related question: Does it matter which rca output the mono sub cable is connected to? Left or Right channel?? i've had it connected to the Left - just curious.

robert1325 · « **Reply #8 on:** 8 Feb 2007, 08:32 pm »

I believe the right one is right...

lcrim · « **Reply #9 on:** 8 Feb 2007, 09:46 pm »

I leave both channels connected to the sub. I had it connected to a single channel at first and the other channel sounded louder like there was a resistance imbalance, but w/ both connected it sounds even. Not very scientific as the sub is so easily triggered but I leave it that way just because.

woodsyi · « **Reply #10 on:** 8 Feb 2007, 09:55 pm »

I have a sum switch on my crossover and my pole is 50 Hz. I should play around with this switch to see what it does. But wait, I have 2 subs. Hhhhhmmmmm. I am going to go check some things out tonight.

Wayner · « **Reply #11 on:** 8 Feb 2007, 11:14 pm »

Bass itself is not stereo by it's nature. The long wavelengths that are required to produce bass tones really put any stereo effect into the null zone. That's why you can put a sub-woofer way off center in a surround system, 'cause it really doesn't matter. Yes. you have to fiddle around with finding the right spot, but when you do, even with the sub-woofer way to the left or right, you hear it coming from the center. Because of this, LP's are mono in the lowest fundamental frequencies. Even if the record companies didn't slope to mono after 50 hz, they would still sound "mono" with regards to the lowest frequencies.

W

Jade East · « **Reply #12 on:** 9 Feb 2007, 12:03 am »

Take your cart and rewire it so one side is out of phase.
Play a record the mono bass signals will cancel each
other out.

Wayner · « **Reply #13 on:** 9 Feb 2007, 12:42 pm »

That's because you just put your speakers out of phase.

W

Jade East · « **Reply #14 on:** 9 Feb 2007, 01:43 pm »

Quote

That's because you just put your speakers out of phase.

With a single sub?

Check out this little page.
http://www.vinylrecorder.com/bass.html

Wayner · « **Reply #15 on:** 9 Feb 2007, 10:48 pm »

Yes, most subs have dual wound voice coils and are in effect if you use the speaker inputs to the sub. Otherwise, if you use the LFE jack, you are getting a mono blend from your source and it has out-of-phase information in it because you put your cartridge out of phase.

W

Russell Dawkins · « **Reply #16 on:** 10 Feb 2007, 05:42 am »

Quote from: Wayner on 8 Feb 2007, 11:14 pm

Bass itself is not stereo by it's nature. The long wavelengths that are required to produce bass tones really put any stereo effect into the null zone. That's why you can put a sub-woofer way off center in a surround system, 'cause it really doesn't matter. Yes. you have to fiddle around with finding the right spot, but when you do, even with the sub-woofer way to the left or right, you hear it coming from the center. Because of this, LP's are mono in the lowest fundamental frequencies. Even if the record companies didn't slope to mono after 50 hz, they would still sound "mono" with regards to the lowest frequencies.

W

In my experience this is correct only in rooms possessing fairly poor to poor acoustics. On second thought I guess it could be said to be generally true!

I have heard absolutely precise and unequivocal imaging on a very deep bass drum on an Andean pan-pipe record (vinyl - Sukay "Pacha Siku"), but this was outdoors, and on fine little transmission lines with KEF B110 drivers.
I had heard this same record on the same equipment indoors in the crummy acoustic of my living room at the time and had no idea there was any imaging happening in the bass. Big surprise.

So bass "is" stereo by nature, and record mastering engineers mono the bass for stylus control reasons as described above.

duggie · « **Reply #17 on:** 10 Feb 2007, 06:27 am »

Quote from: gooberdude on 8 Feb 2007, 08:24 pm

i posted the same question at the Vinyl Asylum and received the same responses....essentially the stylus would have a tough time with stereo bass under 50hz or so.

this saves me some $, thanks so much guys!

A related question: Does it matter which rca output the mono sub cable is connected to? Left or Right channel?? i've had it connected to the Left - just curious.

goober, you're making a big mistake going w/only one sub, imo. stereo subs will improve *everything* about your sound. soundstaging, smooth bass response, tighter, more accurate, less distorted bass, better room loading, you name it.

duggie · « **Reply #18 on:** 10 Feb 2007, 06:49 am »

Quote from: duggie on 10 Feb 2007, 06:27 am

Quote from: gooberdude on 8 Feb 2007, 08:24 pm
i posted the same question at the Vinyl Asylum and received the same responses....essentially the stylus would have a tough time with stereo bass under 50hz or so.

this saves me some $, thanks so much guys!

A related question: Does it matter which rca output the mono sub cable is connected to? Left or Right channel?? i've had it connected to the Left - just curious.

goober, you're making a big mistake going w/only one sub, imo. stereo subs will improve *everything* about your sound. soundstaging, smooth bass response, tighter, more accurate, less distorted bass, better room loading, you name it.

and furthermore!

if you don't wanna take *my* word for it, check out what brian cheney says about stereo vs mono bass in this thread:
http://www.audiocircle.com/index.php?topic=36133.0

Psychicanimal · « **Reply #19 on:** 10 Feb 2007, 09:48 pm »

You won't see someone with properly set up stereo subs going back!

There are future plans for dual mono outboard power supplies for my already Dan Wright modded Marchand electronic x-over (X-9 Deluxe).

I use four monoblock power amps and a dual mono phono pre (Monolithic PS-1) in my sat/sub setup. The stereo separation is simply stunning.