Go read here about the AKSA tone control aplication
http://www.diyaudio.com/forums/aksa/152031-aspen-headphone-amp-73.html#post1968993
http://www.diyaudio.com/forums/aksa/152031-aspen-headphone-amp-73.html#post1968993
Thanks Nico but I'm a little unclear about which circuit you like. Is it this?
http://www.diyaudio.com/forums/atta...8-aspen-headphone-amp-hpampvolbaldeftone1.gif
or this?
file:///C:/DOCUME~1/Linda/LOCALS~1/Temp/loudness.bmp
Sure sound a lot more complicated than it has to be. My Denon must use some electronic version as there is no manual pot. just access through the remote. They have "sound direct" and unless you have very revealing speakers, the difference when switching to the tone control circuit is virtually inaudible.
http://www.diyaudio.com/forums/atta...8-aspen-headphone-amp-hpampvolbaldeftone1.gif
or this?
file:///C:/DOCUME~1/Linda/LOCALS~1/Temp/loudness.bmp
Sure sound a lot more complicated than it has to be. My Denon must use some electronic version as there is no manual pot. just access through the remote. They have "sound direct" and unless you have very revealing speakers, the difference when switching to the tone control circuit is virtually inaudible.
Problem with the Baxandal eq. is that it continues boosting the treble and bass to the full frequency extremes. This overdrives the woofer and I also have a room resonance at 40hz.
So even though adding a midrange eq. to the treble and bass was said to be a bad idea, as you can see from the picture, by decreasing all 3 - bass, midrange, and treble, you get two boosts centered at 100 hz and 4kHz. Juts have to adjust the caps to move the treble boost up to 10,000hz. Mfg said they would help me but never did respond. Anyone here know how?
Well, once again I cannot upload the pic so please go to this link:
Three Band Tone Control PCB (Bass, Mid, Treble) Stereo - eBay (item 280323852189 end time Mar-07-11 08:56:27 PST)
and scroll down the page to "Frequency Response"
So even though adding a midrange eq. to the treble and bass was said to be a bad idea, as you can see from the picture, by decreasing all 3 - bass, midrange, and treble, you get two boosts centered at 100 hz and 4kHz. Juts have to adjust the caps to move the treble boost up to 10,000hz. Mfg said they would help me but never did respond. Anyone here know how?
Well, once again I cannot upload the pic so please go to this link:
Three Band Tone Control PCB (Bass, Mid, Treble) Stereo - eBay (item 280323852189 end time Mar-07-11 08:56:27 PST)
and scroll down the page to "Frequency Response"
It is not a question of like or dislike, what I showed there is the difference in responce between an invering and non=inverting feed back tone control. The inverting version is technically better when applied as a tone control simply because the gain setting is a linear ratio while that of the non-inverting type is not.
I hope that you follow esle ask again.
Nico
Chuck, is there no filter on the amp input. Normally a series capacitor would attenuate the low frequency below some chosen point. You can also add an RC filter before the tone control. In days gone by these were called rumble filters and prevented your woofer cone from jumping out the box playing a warped record. You can do the same for the high side by adding a filter. Filters can be simple or complex.
For instance on the low frequency side you can use an eigth order eliptical filter that will cut at around 80 dB per octave with <1 dB pass-band ripple, thus at 20Hz you can have the full effect +20 dB of your bass control while at 10 Hz this will be 60 dB (1000 x) down. Even if you had a 1000 watt amplifier only about 1 watt will reach the woofer at 10 Hz.
Sounds good. I would like to attenuate below 50 hz and above about 13,00khz. Where would I put this? Do you know the value?
The schematic is on this page here:
Three Band Tone Control PCB (Bass, Mid, Treble) Stereo - eBay (item 280323852189 end time Mar-07-11 08:56:27 PST)
Thanks
Thanks Nico, but the circuit I am using does not have this, I believe.
Three Band Tone Control PCB (Bass, Mid, Treble) Stereo - eBay (item 280323852189 end time Mar-07-11 08:56:27 PST)
If you look at the frequency response for this circuit (it is shown on the page just below the schematic) , there is no LF attenuation. Also I want to move the intersection of the mid and treble tone control up to 10,000 hz. Any idea how to do this?
Three Band Tone Control PCB (Bass, Mid, Treble) Stereo - eBay (item 280323852189 end time Mar-07-11 08:56:27 PST)
If you look at the frequency response for this circuit (it is shown on the page just below the schematic) , there is no LF attenuation. Also I want to move the intersection of the mid and treble tone control up to 10,000 hz. Any idea how to do this?
Doesn't really make sense to me. 56K is not a frequency. If this is a global High-pass filter (an RC filter as you called it) what capacitance would change the value from the designed 20 hertz to, say, 30 hertz? Using your equation it looks like the tone control cuts off at 12.9 hertz. Is that what you calculate?
I calculate for 30 hertz R would be 24K? I don't understand the capacitor changing "roll-off". Isn't this"<1 dB pass-band ripple" for the cap? I don't see a slope here.
If so, I will change the input resistor to 24K. I don't know what the .22uF cap is for or what it will change.
But what I am more interested in the the intersection of the mid and treble cut. You are saying I can change the slope so the intersection is 10,000 hertz, not the 4,000 hertz shown? I am seeing a 47nF, 22nF, and 4.7 nF cap. Are these what should be changed to change the slope? What is the equation to calculate this?
Thanks again.
"Problem with the Baxandal eq. is that it continues boosting the treble and bass to the full frequency extremes. This overdrives the woofer and I also have a room resonance at 40hz."
This is a high pass filter. It was your first question, how do you prevent bass boost to extend down to DC.
I am not quite sure I understand your last question. The tone controls really are just RC networks placed inside the negative feed-back loop of the op-amp. You can tune it to any desired frequency.
This is a high pass filter. It was your first question, how do you prevent bass boost to extend down to DC.
I am not quite sure I understand your last question. The tone controls really are just RC networks placed inside the negative feed-back loop of the op-amp. You can tune it to any desired frequency.
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First off this might appear stupid and the reason being that I know next to nothing about electronics.
During the time I spent in recording studios I've been taught that with regards to sound quality cutting is always preferable to boosting.
With that in mind would it not be a good idea to implement loudness control in a way that it attenuates the mid range rather than boosting bass and treble?
Should be possible to make it variable and connect it to the volume pot so that as the volume rises the cut reduces until reaching 0dB at a predetermined point.
Might be possible to implement the whole thing passively and so avoiding any extra opamps.
Just a thought…
During the time I spent in recording studios I've been taught that with regards to sound quality cutting is always preferable to boosting.
With that in mind would it not be a good idea to implement loudness control in a way that it attenuates the mid range rather than boosting bass and treble?
Should be possible to make it variable and connect it to the volume pot so that as the volume rises the cut reduces until reaching 0dB at a predetermined point.
Might be possible to implement the whole thing passively and so avoiding any extra opamps.
Just a thought…
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