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Odd Audio Output or Bad Digital?

Odd Audio Output or Bad Digital?

2014-03-25 by <Mehlhaffer@...>

About a year ago, a friend of mine gave me a K5m, but as soon as I got it, I was completely disappointed in the sound. Everything was so thin, dull, and wimpy. Frustrated, I quickly blamed it on the early digital design, since it fit the description of how early digital synthesis is usually criticized.

Finally, after a little research, I was wondering if it might be an output problem.
Before, I simply sent its 1/4 inch audio outputs to the audio board to a nominal line level with a flat EQ. Pretty basic stuff, right? As you read this, keep in mind that I also use a variety of other gear, like a Roland Alpha Juno 1 and an Ensoniq ASR-10, that respond just fine on my audio board with those same simple settings. But after experimenting through headphones and my PA amp, I finally decided to try some radical shifts on my audio board. I first set the Trimpot gain on my board up very high, more of where you would gauge it for a microphone level, just before the synth starts to peak into distortion. In order to do this, the volume control on the K5 is now set at about 40-50%. Yes, I know this is against everything people tell you to do with a volume control on a digital synth, but hear me out: It improved the sound incredibly! It created a much bolder, immediate sound, without much for distortion or noise.
Related to this, I also experimented with a line-matching transformer to plug it into a 3-pin XLR. I might have detected a slightly cleaner signal, but the sound hadn't changed that much at all, so I resumed plugging it into the 1/4 inch line inputs.
The next thing I did was radically shift the 3-band EQ. I have the treble turned almost all the way down, about a 15dB cut! The midrange is cranked up about 15dB, and the lows are boosted about 12dB.
After changing all of this, low and behold, everything sounds completely normal. The synth voices are much more rounded, natural, and musical. There is some general digital aspects to the sound, but it's got a character all its own! In fact, I really like the synth now, and I'm hearing all the good stuff I've been missing!

And if that weren't enough, I was even more surprised that the keyboard action from my MIDI controller now responds much better to my touch with the K5, probably because cranking up the trim gain added some compression to the dynamic range of the audio.
Now, here's where it gets weirder. I also have an Alesis QS6.2, which, like the K5, I found to be thin and dull, so I performed the same procedure with it, and now it sounds much, much better in the same way, but at the same time, my ASR-10 and Juno behave perfectly normal with normal mixer settings!

So through all these changes, at first I thought I was clearing up the digital idiosyncracies of the K5, but now I'm wondering if it has something to do with it's output impedance being different. Ever since I made those changes, it seems to sound and respond perfectly normal, like it seems to be intended for. So, how do you connect your K5 to the mixer? It doesn't seem like it should be a big deal, but these changes made a huge difference!

I always figured that most synthesizers should have the same audio output to a basic line level. Am I missing something? I've never really seen anything like this in over 20 years!

Thanks!

-Paul

Re: [k5synth] Odd Audio Output or Bad Digital?

2014-03-25 by Narfman96 - Narfland Studio

Hi Paul,

I recently modified a K5 to increase the output gain and clean up the noise floor. The 150k  gain resistors made a huge improvement. I installed TL2074 op-amps to clean up the noise. These mods made the K5 come alive compared to the stock low gain setup for the TL064 chips. The slew rate of the new op-amps is so much higher the bass and lower mids are very much improved!!! Probably the same as your EQ setup you are currently using.

Awesome you improved the sound without going under the hood,  Fran
Show quoted textHide quoted text
On Tuesday, March 25, 2014 1:15 AM, "Mehlhaffer@..." <Mehlhaffer@...> wrote:
  
  
>About a year ago, a friend of mine gave me a K5m, but as soon as I got it, I was completely disappointed in the sound.  Everything was so thin, dull, and wimpy. Frustrated, I quickly blamed it on the early digital design, since it fit the description of how early digital synthesis is usually criticized.
>
>
>Finally, after a little research, I was wondering if it might be an output problem.
>Before, I simply sent its 1/4 inch audio outputs to the audio board to a nominal line level with a flat EQ.  Pretty basic stuff, right? As you read this, keep in mind that I also use a variety of other gear, like a Roland Alpha Juno 1 and an Ensoniq ASR-10, that respond just fine on my audio board with those same simple settings. But after experimenting through headphones and my PA amp, I finally decided to try some radical shifts on my audio board.  I first set the Trimpot gain on my board up very high, more of where you would gauge it for a microphone level, just before the synth starts to peak into distortion.  In order to do this, the volume control on the K5 is now set at about 40-50%.  Yes, I know this is against everything people tell you to do with a volume control on a digital synth, but hear me out: It improved the sound incredibly! It created a much bolder, immediate sound, without much for distortion or noise.
>Related to this, I also experimented with a line-matching transformer to plug it into a 3-pin XLR.  I might have detected a slightly cleaner signal, but the sound hadn't changed that much at all, so I resumed plugging it into the 1/4 inch line inputs.
>The next thing I did was radically shift the 3-band EQ.  I have the treble turned almost all the way down, about a 15dB cut! The midrange is cranked up about 15dB, and the lows are boosted about 12dB.
>After changing all of this, low and behold, everything sounds completely normal.  The synth voices are much more rounded, natural, and musical.  There is some general digital aspects to the sound, but it's got a character all its own! In fact, I really like the synth now, and I'm hearing all the good stuff I've been missing!
>
>
>And if that weren't enough, I was even more surprised that the keyboard action from my MIDI controller now responds much better to my touch with the K5, probably because cranking up the trim gain added some compression to the dynamic range of the audio. 
>
>Now, here's where it gets weirder.  I also have an Alesis QS6.2, which, like the K5, I found to be thin and dull, so I performed the same procedure with it, and now it sounds much, much better in the same way, but at the same time, my ASR-10 and Juno behave perfectly normal with normal mixer settings!
>
>
>So through all these changes, at first I thought I was clearing up the digital idiosyncracies of the K5, but now I'm wondering if it has something to do with it's output impedance being different.  Ever since I made those changes, it seems to sound and respond perfectly normal, like it seems to be intended for.  So, how do you connect your K5 to the mixer? It doesn't seem like it should be a big deal, but these changes made a huge difference!
>
>
>I always figured that most synthesizers should have the same audio output to a basic line level.  Am I missing something? I've never really seen anything like this in over 20 years! 
>
>
>Thanks!
>
>
>-Paul  
>   
>
>

Re: [k5synth] Odd Audio Output or Bad Digital?

2014-03-26 by Paul Mehlhaff

Fran: Thank you for the feedback!  That definately sounds similar to what I am experiencing! I'll have to keep the upgrade in mind for the future, but in the meantime, I'm really happy with my board settings.  Now, I have a chance to build some patches on this thing!

Damian: You're right about effects.  One of the other things I add is a very heavy dose of chorus effect or delay.  I mostly output a mono-mix signal, so this creates some thickness and stereo imaging. After doing that it did remind me much more of a D-50 sound.




On Tuesday, March 25, 2014 4:42 PM, Narfman96 - Narfland Studio <narfman96@...> wrote:
 



Hi Paul,

I recently modified a K5 to increase the output gain and clean up the noise floor. The 150k  gain resistors made a huge improvement. I installed TL2074 op-amps to clean up the noise. These mods made the K5 come alive compared to the stock low gain setup for the TL064 chips. The slew rate of the new op-amps is so much higher the bass and lower mids are very much improved!!! Probably the same as your EQ setup you are currently using.

Awesome you improved the sound without going under the hood,  Fran
Show quoted textHide quoted text
On Tuesday, March 25, 2014 1:15 AM, "Mehlhaffer@..." <Mehlhaffer@...> wrote:
 
  
>About a year ago, a friend of mine gave me a K5m, but as soon as I got it, I was completely disappointed in the sound.  Everything was so thin, dull, and wimpy. Frustrated, I quickly blamed it on the early digital design, since it fit the description of how early digital synthesis is usually criticized.
>
>
>Finally, after a little research, I was wondering if it might be an output problem.
>Before, I simply sent its 1/4 inch audio outputs to the audio board to a nominal line level with a flat EQ.  Pretty basic stuff, right? As you read this, keep in mind that I also use a variety of other gear, like a Roland Alpha Juno 1 and an Ensoniq ASR-10, that respond just fine on my audio board with those same simple settings. But after experimenting through headphones and my PA amp, I finally decided to try some radical shifts on my audio board.  I first set the Trimpot gain on my board up very high, more of where you would gauge it for a microphone level, just before the synth starts to peak into distortion.  In order to do this, the volume control on the K5 is now set at about 40-50%.  Yes, I know this is against everything people tell you to do with a volume control on a digital synth, but hear me out: It improved the sound incredibly! It created a much bolder, immediate sound, without much for distortion or noise.
>Related to this, I also experimented with a line-matching transformer to plug it into a 3-pin XLR.  I might have detected a slightly cleaner signal, but the sound hadn't changed that much at all, so I resumed plugging it into the 1/4 inch line inputs.
>The next thing I did was radically shift the 3-band EQ.  I have the treble turned almost all the way down, about a 15dB cut! The midrange is cranked up about 15dB, and the lows are boosted about 12dB.
>After changing all of this, low and behold, everything sounds completely normal.  The synth voices are much more rounded, natural, and musical.  There is some general digital aspects to the sound, but it's got a character all its own! In fact, I really like the synth now, and I'm hearing all the good stuff I've been missing!
>
>
>And if that weren't enough, I was even more surprised that the keyboard action from my MIDI controller now responds much better to my touch with the K5, probably because cranking up the trim gain added some compression to the dynamic range of the audio. 
> 
>Now, here's where it gets weirder.  I also have an Alesis QS6.2, which, like the K5, I found to be thin and dull, so I performed the same procedure with it, and now it sounds much, much better in the same way, but at the same time, my ASR-10 and Juno behave perfectly normal with normal mixer settings!
>
>
>So through all these changes, at first I thought I was clearing up the digital idiosyncracies of the K5, but now I'm wondering if it has something to do with it's output impedance being different.  Ever since I made those changes, it seems to sound and respond perfectly normal, like it seems to be intended for.  So, how do you connect your K5 to the mixer? It doesn't seem like it should be a big deal, but these changes made a huge difference!
>
>
>I always figured that most synthesizers should have the same audio output to a basic line level.  Am I missing something? I've never really seen anything like this in over 20 years! 
>
>
>Thanks!
>
>
>-Paul 
>
>

Re: Odd Audio Output or Bad Digital?

2014-04-03 by <Mehlhaffer@...>

OK here's some more results and an audio test:
This is an A/B test over several different types of patches.
The "A" version is a stereo signal from INDIVIDUAL OUTS 1&2 going into a board under a normal line level with a flat EQ and the "B" version is the settings I described earlier, with the increase in trim gain, Cut in the high EQ, boost in the mids, and boost in the lows. I adjusted the volumes of the A and B sections so they matched more in perceptual volume.
The results? After listening to this in several speakers and headphones, I can easily hear that I over-did it! I found it doesn't have to be quite as harsh a change! I think the color of my PA speakers was tricking my ears the most, and I really over-processed the sound!
So, here's what I think so far:
-The highs can generally use a little bit of roll-off to reduce the aliasing noise. You can hear it does give a smoother quality to the sound, but when I cut it all the way down, we do lose way too much brightness.
-The mids can be boosted a little, but now I think this is adjusted more to taste. When I viewed the waveforms in a spectrum analyzer I could see that the K5 has a rock-solid flat response. Messing with the mids a little can make it a little more non-linear in the EQ, You might like it.
-Increase in Bass should be discerned carefully. Most patches could probably use a little bass, but in the demo, you can hear that I over-did it.

-As for the gain increase on the board, I also made another audio test where on both the A and B sections the EQ is flat, with only the trim gain changed. I was expecting a huge change, but in reality, there was not a whole lot of difference. There may be some slight compression or analog distortion, but in close comparison, it just did not change much at all!

WHAT IT COMES DOWN TO IS SIMPLY ADJUST THE SOUND ON A CASE-BY-CASE BASIS. Some patches are programmed with different sound in mind. What works for a flute patch may not work for a bass or a bell sound. And the synth has a lot of variance between the sounds. Luckily, the K5 has the Digital Formant Filter which can shape the EQ for each patch.


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