Bass/Treble Turnover - explanation?

just got a new receiver, my grandfather's old Pioneer SX-838 which had been sitting unused in his house for years and years. everything is in good shape and i'm playing music through it right now.

can someone explain to me in non-technical terms what the "bass turnover" and "treble turnover" switches do? the bass turnover switch can be set to 400Hz or 200Hz, and the treble turnover switch can be set to 2.5 kHz or 5 kHz.

is this a matter of personal preference, or is there a standard/default setting?

what should be happening to the sound as i toggle the switches? the bass sounds fuller and deeper at 400 Hz than at 200Hz. there doesn't seem to be a huge difference w/ the treble (although i do hear a crackle/static when i switch it up from 5 kHz to 2.5 kHz, maybe it's not working as it should?).

thanks for any info.

 

It's simply the center frequency of the bass or treble control that you're changing. If the bass control turnover is set at 400hz then the control is going to adjust (boost or cut) the frequencies around 400hz the most.

 

These seem like rather odd frequencies for shelving bass and treble controls. I'd expect them to be lower and higher. I've heard the term turnover used before to describe the eq pivot points for preset equalizer curves such as NAB, IEC, and RIAA. I did look at this receiver on the web and it does not seem old enough to have NAB equalizers. Many old units from the 50's did since people would plug tape heads directly into them. Most all modern tape decks had their own tape preamps with internal eq. I'm a bit confused with one, but I guess I'll have to yield to what Steve and Grumpy said.

 

I always thought for a bass/treble control it meant the frequency where the tone control will stop taking effect - ex. the center point of the bass control in this Pioneer receiver might be 100 cycles, but a boost or cut to the control will affect frequencies upwards to either 200hz (for a narrower curve) or 400hz (for a wider curve). Guess I was wrong...

 

Has there been a standard for bass and treble controls? For example, 100Hz for bass and 10KHz for treble?