What's the word on mixing bass?

[bentoronto]

Very glad to discover this website as I am renewing my interest in audio building. Or possibly audio downsizing.

I've been a confirmed adherent of mixed bass audio for 40 years or so, currently using 5 amplifiers and driving a single amp to a single Klipschorn bass (built in early 50s, I think) in the range up to 140 Hz, with a 50 year old South West Technical amp.

Thought I'd ask: what is the state of current thinking about mixing bass? In particular, are people feeling there is a downside? Or any reason not to use a simple resistor mixer?

[PeteMcK]

probably depends on the music you listen to, some electronic music has stereo effects in the low bass nowdays. Personally, I'm not in favour of subs, drivers now are good enough that well designed woofers will cover the range more than adequately...

[bentoronto]

Peter - many thanks.

I appreciate that kind of information. But... if there's no sense of direction with low bass, what difference would it make what the "composer" thought he/she was trying to do? (That's a real question, not a rhetorical one.)

I'm none too clear where woofer ends and sub begins. In most respects, we divide the frequency compass by equal octaves, thinking that apportions the effort (and in most respects, the design challenges) fairly enough. With bass, there's also the point-of-no-directionality below which we might as well have a single speaker. I'm still inclined to believe the cost-effective approach is to create a single really great woofer because the cost of making two would be steep (that is, double).

[bentoronto]

.... and there may be only one good woofer location in your listening room. Or others in the household may have their own ideas for large square furnishings.

[leadbelly]

I'm surprized that you didn't get more of a response. Probably because this has been debated ad nauseam. A little searching would get you some good threads. Personally, I'm on the pro-stereo-woofers side of the debate. IMHO the significant distortion caused by the sub driver makes a mono sub very localizable, and makes stereo subs the preferred option.

[bentoronto]

Originally posted by leadbelly
I'm surprized that you didn't get more of a response. Probably because this has been debated ad nauseam. A little searching would get you some good threads. Personally, I'm on the pro-stereo-woofers side of the debate. IMHO the significant distortion caused by the sub driver makes a mono sub very localizable, and makes stereo subs the preferred option.

Thanks.

I searched as best as I could for about a half-hour (and there's that 20/minute time-out too). All variations of mixed, blended, mono, bass, etc., titles and posts, etc. Any help searching such as key words or phrases would be appreciated.

Yes, the distortion products and noise can make the woofers localizable, if they are bad enough. With a low enough woofer crossover, the distortion products should still be barely localizable. But given the benefits of corner location for eking out the lowest notes, easy to get locked-into certain few locations in the room.

[iUSERTLO72p]

single Klipschorn bass (built in early 50s, I think) in the range up to 140 Hz, with a 50 year old South West Technical amp

Hey bentoronto, got any pics?


iUSERTLO72p

[bentoronto]

Picture of Klipschorn? HIding right behind my right D-W in the only good corner in my not large music room... corners big enough for a K-horn are hard to find.

Started life as a utility horn, meaning no veneer and no top. Needs a top to seal off the top edge of the exit mouth and I made one from 25 lbs of particle board. Finished the top and the front with luan mahagonny (striped, nice stuff), bad spelling. Very easy to buy, contact cement, and trim such veneers and then to finish with a gel stain. A nice feature of a Klipschorn is that you can rest a whole lot of cinderblocks or wine bottles on top, always a good move for a woofer, even if least needed for a horn.

Or are you asking for a picture of the antique SWTP amp with the speaker protector circuit (mostly for turn-on turn-off transients) and the extra power supply caps lying on the carpet next to it? Klipsch said "give me 5 clean watts" or something like that.

[Conrad Hoffman]

Last I understood, bass was only non-directional when it was mixed that way by the studio, which was apparently common practice. Modern recordings may have stereo information all the way down, and a stereo subwoofer setup is probably to be preferred unless the room precludes it. OTOH, there are some really fine single sub systems, so I wouldn't lose any sleep over it. IMO, subs are great if they can be smoothly integrated with the rest of the system. To me, that means a sealed box mid-bass/main system, not a reflex, and a properly designed crossover. The sub can be any design one likes.

[bentoronto]

Originally posted by Conrad Hoffman
Last I understood, bass was only non-directional when it was mixed that way by the studio, which was apparently common practice. Modern recordings may have stereo information all the way down, and a stereo subwoofer setup is probably to be preferred unless the room precludes it. OTOH, there are some really fine single sub systems, so I wouldn't lose any sleep over it. IMO, subs are great if they can be smoothly integrated with the rest of the system. To me, that means a sealed box mid-bass/main system, not a reflex, and a properly designed crossover. The sub can be any design one likes.

As far as I know (and that's pretty rusty) two things have to be kept separate. There can be all kinds of disparate stuff on the channels of a recording, but they get mixed in your room when the frequency is low. If it is true, as I believe it is, that you have no ability to sense direction of a source below maybe 140 Hz, might as well have one quality source. (If you have a super tweeter - and a loudish one - like an ion wind, all the sound seems to come from the little blue glowing tube.)

Some of the stuff that is different on any channels of the recording is accidental and due to factors of the room where the recording took place. Some of that wave informs the listener about the concert room (if any), but that is not because of any directionality of the sound or the disparity between the two channels.

Likewise, some of the stuff that reaches your ears as a results of identical low frequency material coming out of speakers in different places in your room, is also accidental and of no significance - or a distortion - when it reaches your head.

So why not just mix the bass and avoid some of the false room effects and the losses arising from having multiple channels doing the same thing (when you could invest time and energy into one excellent woofer doing all the woofing well)?

My mixed bass corner horn (cross-over around 140 Hz, 24 db/8ave) sits right behind my right speaker. But there is no sense that any bass emphasis is coming from that side.

BTW, I share your preference for sealed and distaste for the very fashionable tuned boxes. A Klipschorn has a sealed box behind the driver.