Impedance Demo: 3 Guitars, 3 Pickups, 5 Impedances

[Cochese]

I have an older Para DI and the manual does state 10MegOhm input impedance.Funny they no longer list the specs. 10K is typical line level input impedance. My Mackie's have that as does the line input on my Summit 2Ba-221.

Just an observation as I appreciate the time that Doug took to do this test. It seems to me it might have been better to hear the Felix recorded direct as a tube amp is more than likely seriously coloring the sound as does the speaker and microphone etc.

I have the D-Tar Wavelength, which just replaced the K&K in my Taylor and I also have the Barbera Soloist and have been experimenting the last few weeks with these pickups and different preamps. I had also found out recently before I swapped the K&K with the Wavelength that the K&K does work into a high Z input on my mixer.

The Barbera is an obvious impedance mismatch. Rich recommends 1MegOhm though it will work with higher input impedance. The main problem I always had with the K&K is when I do percussive techniques it would overload the PADI. This may in part be due to it being a 9 volt system. I'm not sure if there is increased headroom when running phantom power. I also found I would have to dial out more low end when using the PADI or the Fishman Platinum Analog Pro EQ which is also 10Meg.

As Doug pointed out hearing the differences in the same preamp takes other factors out of the equation. Oddly though not scientific I found the Wavelength sounded pretty much the same through my Mackie's 10K line inputs and my Great River ME-1NV high Z (1.2MegOhm) input. The GR does sound better but there isn't a huge shift in frequency response. The Wavelength into my Summit preamp sounded pretty much the same into the 10K line input and the 1.7megOhm High Z input. Same with my Groove Tubes Brick 3MegOhm input. There are differences but every preamp will have a sound.

My take after listening to Doug's clips and my own tests is that impedance is only part of the story as long as the pickups are not being adversely affected as in the case of the Barbera into the 10K input. That's an obvious mismatch where the difference between 1-10Meg is more about different coloration and response.

The reason manufacturers don't list the impedance is that it is frequency dependent and not a simple resistance measurement. Pickups have a resonant peak and the impedance will change at different frequencies.

[Doug Young]

I thought about recording direct, but im kind of tired of how bad pickups sound direct :-), and playing thru an amp is a much more realistic test of how we're really going to perform. My main regret is that to me, these recordings dont sound as good as the guitars ( at the higher impedance settings) sounded in person. I havent mastered recording an amped acoustic, clearly. Not some thing expect to have much neeed for, of course.

[jomaynor]

Thanks for another enlightening comparison, Doug. The differences in tonal change with each impedance change (other than the outlier 10k) are quite subtle for each guitar.

Much more apparent were the sonic qualities of each guitar and pickup system, when set to a suitably high impedance, like 10M or 20M.
Here are my impressions:

Ryan/K&K: pleasingly mellow, and the politest sounding of the three.

Hamblin/Barbera: very overtone rich, with a sparkling top end.

Martin/Wavelength: a pleasant surprise, this one - well balanced mids, with a clear top end.

[guitaniac]

Originally Posted by Cochese

I have an older Para DI and the manual does state 10MegOhm input impedance.Funny they no longer list the specs. 10K is typical line level input impedance. My Mackie's have that as does the line input on my Summit 2Ba-221.



The reason manufacturers don't list the impedance is that it is frequency dependent and not a simple resistance measurement. Pickups have a resonant peak and the impedance will change at different frequencies.

I was thinking that 20K ohms to 50K ohms is more typical for a mixer input. I'll have to try and find the manual for my own Mackie mixer. (Things have been "rearranged" since moving.) PS I found some Mackie manuals online. My own mixer's (1202VLZ4) line inputs are listed as "10K ohms or more". For one of the FX series mixers which I checked, the line inputs were listed as 20K ohms.

I was aware that impedance changes with the frequency, but thought that it was customary to use a default frequency (1000 Hz?) for purposes of stating impedance values. In any event, the fact that impedance changes with frequency is why you lose more low end than high end when running to an insufficient input impedance.

Looking at the Fishman Prefix Blender stats just now, I see that they list the output impedances like this

Output Impedance (tip): Less than 3.5 k Ohms (the UST, I presume)
Output Impedance (ring): Less than 6.6 k Ohms

Obviously, if you happen to have 3K ohms impedance looking into 10K ohms impedance you're gonna have some degraded signal (by Rick Turner's rule of thumb, at least).

Fishman's discontinued Ellipse Blender has a listed output impedance of 1K ohm, with a recommended load of 10K ohms and up. That's consistent with Rick turner's rule of thumb.

It does appear that Fishman has discontinued the practice of listing output impedances with some newer products like the Matrix Infinity.

[Yamaha Man]

Originally Posted by Doug Young

I thought about recording direct, but im kind of tired of how bad pickups sound direct :-), and playing thru an amp is a much more realistic test of how we're really going to perform. My main regret is that to me, these recordings dont sound as good as the guitars ( at the higher impedance settings) sounded in person. I havent mastered recording an amped acoustic, clearly. Not some thing expect to have much neeed for, of course.

I have to agree that pickups don't always sound so great when recording them, but I'm still trying to master that because direct in recordings are free from room noise. In my home studio, room noise and environmental noises are really a problem, so it's a chore to get a good recording using a mic or two. A direct in recording isn't ruined when a dog starts barking, the phone rings, the neighbor decides to mow his grass, or a car with a bad muffler drives by...these are real life situations I have to deal with in my home studio.

[guitaniac]

I'm with you on the home recording thing, Martin Maniac. Perhaps its a futile search, but I'm still hoping to find that UST or in-saddle-transducer which doesn't quack (with aggressive strumming) when recorded directly and blended with the MiniFlex 2Mic.

There's probably a greater likelihood that I'll eventually be able to afford my own recording studio on a remote desert island.

However, Doug Young, it would be very interesting to me to hear a direct recording of some heavy strumming on that Hamblin/Barbera rig. Just sayin.

[dberkowitz]

Doug, how do you like the Felix in terms of sonics/flexibility/price point, etc. against the Radial, Baggs, and Avalon?

[Shoreline Music]

Doug—thanks for doing this. As with everything you have to add here, it's exceedingly helpful.

-J

[Doug Young]

Originally Posted by Martin Maniac

I have to agree that pickups don't always sound so great when recording them, but I'm still trying to master that because direct in recordings are free from room noise. In my home studio, room noise and environmental noises are really a problem, so it's a chore to get a good recording using a mic or two. A direct in recording isn't ruined when a dog starts barking, the phone rings, the neighbor decides to mow his grass, or a car with a bad muffler drives by...these are real life situations I have to deal with in my home studio.

My solution to that is iZotope RX. Dont you use Audition? A lite version is built in. A $5 mic sounds better than the best pickups I know of. Its just not worth the effort, to me, to record with a pickup. You can just record in between the noises :-)

[philjs]

Originally Posted by Martin Maniac

I have to agree that pickups don't always sound so great when recording them, but I'm still trying to master that because direct in recordings are free from room noise. In my home studio, room noise and environmental noises are really a problem, so it's a chore to get a good recording using a mic or two. A direct in recording isn't ruined when a dog starts barking, the phone rings, the neighbor decides to mow his grass, or a car with a bad muffler drives by...these are real life situations I have to deal with in my home studio.

Don't want to sidetrack Doug's superlative work (again) but for those folks (eg. Martin Maniac and guitaniac in this thread) trying to record acoustic direct and who have UAD hardware, I wonder if the new Sound Machine/UAD "Wood Works" plugin would help you out? It's not cheap but if you have the hardware then it might be a working solution...the demos sound quite good, I think.

Phil

[Yamaha Man]

You should know, you're the one with a whole webpage dedicated to recorded pickups !!

I haven't had a chance to record direct with the AT2020 mic you recommended in one of your video. I have used it last week to record my amp and it sounded best of all. Thank You !!

[Doug Young]

Originally Posted by philjs

Don't want to sidetrack Doug's superlative work (again) but for those folks (eg. Martin Maniac and guitaniac in this thread) trying to record acoustic direct and who have UAD hardware, I wonder if the new Sound Machine/UAD "Wood Works" plugin would help you out? It's not cheap but if you have the hardware then it might be a working solution...the demos sound quite good, I think.

Phil

I hadnt seen that, thanks for the pointer. Im a big UAD fan, ill have to check it out.

[Cochese]

Originally Posted by Doug Young

I thought about recording direct, but im kind of tired of how bad pickups sound direct :-), and playing thru an amp is a much more realistic test of how we're really going to perform. My main regret is that to me, these recordings dont sound as good as the guitars ( at the higher impedance settings) sounded in person. I havent mastered recording an amped acoustic, clearly. Not some thing expect to have much neeed for, of course.

I guess it depends on your application but most acoustic work I've done over the years is direct into a sound system. You're to be applauded at getting that great of a sound mic'ing an acoustic amp with a tweeter. There are usually all sorts of phase issues usually involved. That seems like a really cool amp though I'm not sure what the intended purpose is at 15 watts. It's a beautiful piece of gear and I'd love to try one some day.

My point was that a direct recording of the Felix would allow us to "hear" the results of the different settings without any additional tone shaping. The Felix is obviously a serious preamp that can be used a multitude of ways, direct being one. Also with acoustic pickups I find most sound decent when fingerpicking, it's the aggressive strumming with a flat pick that turns them into cellophane city. Instant Dave Matthews tone.

In general I think we should differentiate between the sound of an actual guitar in a room vs good "recorded" tone and good "live" tone. Recording is not a transparent process. I was listening to Don Ross yesterday and he sounds fantastic but to me that is a stellar recorded tone and I've never heard any guitar sound like that in person. That in your face, immediate sound with lush reverb where it sounds like your listening inside the guitar. Like the Michael Hedges stuff. More of a conceptualized idealistic tone versus the most honest representation of the guitar itself.

While we do consider microphones the "gold" standard the average condenser mic will add a high end sheen that the human ear doesn't normally hear. In a perfect world...

[Doug Young]

Originally Posted by dberkowitz

Doug, how do you like the Felix in terms of sonics/flexibility/price point, etc. against the Radial, Baggs, and Avalon?

I thnk the Felix is hitting all the right notes. Built like a tank, and sounds excellent. Lots of routing options in a convenient package. Its competition is probably the Pendulum, but in a smaller floor mount. For me, a huge win over the ones you mention is dual channel, with both 48 and 12 volt power, plus XLR mic input. And 60db of gain if you need it. +20dbu output, too. 2 separate DI outs, each selectable between 2-channel mix, or individual channels. It isnt cheap, of course, but its less than a pendulum, and more convenient for stage use.

[Doug Young]

Originally Posted by Cochese

I guess it depends on your application but most acoustic work I've done over the years is direct into a sound system. You're to be applauded at getting that great of a sound mic'ing an acoustic amp with a tweeter. There are usually all sorts of phase issues usually involved. That seems like a really cool amp though I'm not sure what the intended purpose is at 15 watts. It's a beautiful piece of gear and I'd love to try one some day.

My point was that a direct recording of the Felix would allow us to "hear" the results of the different settings without any additional tone shaping. The Felix is obviously a serious preamp that can be used a multitude of ways, direct being one. Also with acoustic pickups I find most sound decent when fingerpicking, it's the aggressive strumming with a flat pick that turns them into cellophane city. Instant Dave Matthews tone.

In general I think we should differentiate between the sound of an actual guitar in a room vs good "recorded" tone and good "live" tone. Recording is not a transparent process. I was listening to Don Ross yesterday and he sounds fantastic but to me that is a stellar recorded tone and I've never heard any guitar sound like that in person. That in your face, immediate sound with lush reverb where it sounds like your listening inside the guitar. Like the Michael Hedges stuff. More of a conceptualized idealistic tone versus the most honest representation of the guitar itself.

While we do consider microphones the "gold" standard the average condenser mic will add a high end sheen that the human ear doesn't normally hear. In a perfect world...

I understand, that's why the 100+ pickup samples on my site are direct. But i constantly hear from people that they wish id done those more "real world" with an amp and EQ. I dont think the amp is hiding anything. If anything, I thought it made the impedance differences more clear. Direct, you just get to compare different degrees of bad. It sounds like you're able to tease that apart, which is what i intended when i created my pickup samples, but many people will just say "they all suck" when listening direct. If i have time, ill do a direct version later this week.