US 16x08 (and US-1800 at least) intrument input tone issue

[el touristo]

I searched threads for this issue, didn't find it. My US-1800 that died did the same thing as my new US16x08. I was hoping the newer one wouldn't do it: trying to record guitars direct has 'rolled off highs'. It doesn't matter where I set the gain control knob, the tone stays the same, only the gain changes. I've compared the sound to and Apogee Duet on the same guitar, same strumming, and pickup etc, and also to a Roland Gp-10. I have two recordings from the US 16x-08 at lowest and middle gain setting, they sound dull and rolled off. It's obviously a problem but I don't know if its addressable. I haven't heard about this but I think if anyone compares their US-1800 or US 16x08 in this way they would find the problem. I would of course love it to addressable. I'm surprised it exists at all. I don't see how it can be as simple as an impedance mismatch, but it sorta sounds 'something like that'. However of course Tascam surely intended these inputs to work with guitars, so I am just lost at this point and just trying to if anyone has found this to NOT be a problem on those two units (and maybe others). I think that if everyone has this experience with (at least) these units, that Tascam would be very concerned with fixing it at least in later designs, or if it's addressable then issuing a memo. Also they should warn people after acknowledging the problem if it's not addressable. Please everyone check your gear. I made a few recording that are quite off. It took me a while to discover this. I guess I mainly started really noticing when I started using the GP-10 as in interface and noticed how much "better" the guitar sounded. Before that I sorta almost thought my guitars just sounded like that, but I was suspicious. Then I eventually figured about by comparison the other interfaces are the way it's supposed to sound ! This is not some minor marginal thing. You will IMMEDIATELY hear a big difference. Make recordings of dry guitar strumming for example , loop them, put them on separate tracks, volume match them (but don't use compression, EQ or any effects). then just solo them back and forth. DRAMATIC difference. Please let me know if you DON"T have this problem too ! Thanks ! Here are my comparison files ! https://www.gearslutz.com/board/mus...-duet-roland-gp-10-compared.html#post14329928

 

[cripple9]

This is interesting. I'd like to see some spectrum analysis of different interfaces. Maybe using white noise or whatever for continuity's sake. Unfortunately, I currently only have Tascam interfaces, and haven't used anything else in a few years, so I can't help you.

 

[cripple9]

It might be useful for us all to start testing our ears with something like this every now and then too.

 

[el touristo]

Ok I got the comparison files together, but when I click "Upload a File" to this post, it says "you do not have permission to view this page or perform this action". I'd like to share these 4 comparison recordings, I can't think of another easy way I have set up to share them. So it would be nice if the upload was working. Maybe because I am a new member? idk. Thanks.

 

[el touristo]

OK I am giving a link to where I put the files on Gearslutz. I hope you can play/download them. Please listen to them, the concern should jump out at you ! https://www.gearslutz.com/board/mus...-duet-roland-gp-10-compared.html#post14329928

 

[cripple9]

There are some pretty stark differences in those recordings for sure. I don't know much about the technical side of interface components, but you wouldn't think the difference in Hi-Z inputs would be so dramatic. It's not like you're running through a mic preamp.

Forgive me if I'm asking anything redundant here, but-

1. Are you using the same bit depth, sample rate, & rendering on all of them? Using the same DAW, computer, operating system, cables, other hardware, etc.?

2. Do you have any DSP/mixer functions enabled on any of the interfaces or in their control software?

-On the US-16x08, do you have the "MIXER TRUE BYPASS" on or off? If the mixer is enabled, do you have any of the effects (EQ/Compression) enabled?

-I'm not sure if the Duet has any effects or not. I think it uses some sort of software limiter (Soft Limit?). Maybe that could saturate the signal a bit?

-With the GP-10, are you using the GK pickup at all? Also, do you have it set to DRY-GUITAR or one of the RE-GUITAR options? I wonder if it actually completely bypasses ALL processing before the signal makes it to the computer, or if it still gets colored by something in the path.

3. Do you have a way to use the exact same audio source or a single re-amp recording to play into the instrument inputs on each interface? That way we could have an actual control sample to run through a spectrum analyser and visually see the differences.


I'd love to see more people compare the instrument inputs from a wide variety of interfaces.

 

[el touristo]

I will try to quickly respond to your questions that I quote:
1. Are you using the same bit depth, sample rate, & rendering on all of them? Using the same DAW, computer, operating system, cables, other hardware, etc.? A: The 16x08 and the GP-10 were recorded on the same computer and DAW with everything like sample and bit rates etc the same. The Apogee Duet is not windows compatible. That file was recorded on my friends mac and sent to me where I volume matched it.

2. Do you have any DSP/mixer functions enabled on any of the interfaces or in their control software? A: No, all of that off or bypassed. The can be no effects, processing, or normalization when doing comparisons like this. The recording were volume matched by ear and meter and no compression or limiting etc could be used.


-On the US-16x08, do you have the "MIXER TRUE BYPASS" on or off? If the mixer is enabled, do you have any of the effects (EQ/Compression) enabled? A: I have the latest firmware and driver/settings panel. I can't manage to get the 'Mixer True Bypass' to EVER be set to OFF. So it is always indicating 'ON'. I do seem to maybe hear that the mixer output is closer to real time than the reported approx 10m round trip when monitoring 'through' the DAW. I can listen to both the mixer and the DAW input , pan them, mix them etc so that way I can get some impression of time differences. I like the mixer it is simple but seems to do the basic thing. The meters are very laggy idk why. Overall the 16x08 seems an appropriate evolutionary step up from the US-1800 which had no mixer and insufficient direct monitoring -mono/no pan and you could not mix them, they were just always on you could only blend them all vs the computer output with that knob. (my US1800 died and this US16x08 is the replacement).

-I'm not sure if the Duet has any effects or not. I think it uses some sort of software limiter (Soft Limit?). Maybe that could saturate the signal a bit? A: We made sure to turn that off.

-With the GP-10, are you using the GK pickup at all? Also, do you have it set to DRY-GUITAR or one of the RE-GUITAR options? I wonder if it actually completely bypasses ALL processing before the signal makes it to the computer, or if it still gets colored by something in the path. A: The GK pickup is not being used, not connected. The unit is set to USB routing: 'DRY-GUITAR'. It does seem to bypass everything nicely.

3. Do you have a way to use the exact same audio source or a single re-amp recording to play into the instrument inputs on each interface? That way we could have an actual control sample to run through a spectrum analyser and visually see the differences. A: I think I understand the intent of your question, but that intention is misplaced for this testing scenario. While is best to compare the exact same source, we can't do that for these sorts of things. Maybe if we had a guitar-strumming robot ! lol. We MUST use an ACTUAL guitar for EACH recording, because we are concerned with how the passive pickup, high impedance guitar signals are recorded by each interface, for comparison of THAT. So we CAN'T use a pre-recorded single source file because that would be a 'line' level type thing. There would be no point, and it would be utterly confounding, and next to impossible, to find a way to somehow convert line level to the exact signal character of a passive guitar pickup. BTW you can 'sortof' do that sort of thing with mic by playing the signal through the same set of monitors the same distance away at same level etc and placing the mic in front of it. Yes that will give you a way to do a controlled comparison of mics or mic inputs. Though I say 'sortof' because of course the monitors are not the same as acoustic signals like voice, drums, acoustic guitar. Though that would be decent for comparing guitar amp speaker sound. This entire thread is because we are comparing guitar signals/loading, not line level input signals, not mic signals. I doubt there are any significant audible differences in line level inputs. I expect some differences in mic pres but that not the scope of this guitar input concern. The concept of using some kind of spectral graphic display is actually not so different across these recording vs is they were the same file. Use your ears and eyes. I havn't bothered trying to roughly name those, or maybe try to make the full range ones sound 'just like ' the duller ones with a single lowpass filter, which would then tell you something about the differences also in terms of about how much is 'missing'. The main concern is that they are so noticeably off, with all other reasonable conditions set to reasonable equivalence. I have emailed the files to Tascam, they say they will try to reproduce the concern. I hope it's something I missed somehow somewhere, that would be best. But it could be an actual issue. I hope we learn more about it soon.

 

[cripple9]

Ok, so I plugged my guitar in for the first time in probably 6 months, lol. When the "MIXER TRUE BYPASS" is checked "ON", that means the mixer effects are disabled. I don't have any issues with bypassing it on my pc (Win 10 x64 Pro v1909 OS Build 18363.476). BUT... I did notice something strange with the Low Cut Filter in the mixer, so there may very well be something wrong with the US-16x08's onboard DSP. When you enable the LCF, it cuts the freq like it should. But when you disable it, the low gain knob snaps all the way down to -12. You have to manually reset it every time.

I made a video showing what I mean -

 

[el touristo]

That's interesting. mine won't switch off* of Mixer True Bypass-as far as the indicator shows,*EDIT- I was reading it wrong, the Mixer True Bypass is ON when the button is DARK. Yeah that's backwards in my book. So yeah my Mixer True Bypass does appear to work. I will prolly just leave it on. I don't care for those DSP there anyway. But I like the mixer for cue monitoring etc. So I just learned that. Windows 10, latest driver and firmware. I can see that LCF maybe acting weird. I don't think the issue I'm experiencing is related to DSP. I'm pretty sure the US-1800 I had did the same thing. It has no DSP. With my Mixer True Bypass saying 'ON', the Effects still work, BUT the EQ shows no graphics change, NO CURVE, just a straight line across the middle. Also if I switch the 'Analog x' button to another channel and switch back the effects are still running but the indicators read as if there was no effects on. (so you can't see where they are set) Also the meters in general, and the gain reduction indication in the compressor are VERY laggy. BTW what software did you use to make the video? thanks

 

[cripple9]

You're right, those meters are way too slow. Anyway, as far as I can tell, all the DSP works as it should for me except for that LCF button issue. I don't really use the effects very often either, so I'll ignore it for now. This US-16x08 has been a PITA from the beginning though, lol. It's nothing but troubleshooting problem after problem every time Windows gets an update. I doubt I'll buy another Tascam in the future, which is sad, cuz I've been using em since the old Porta02mkII. Hopefully they get their issues straightened out soon.

I went back through some old projects that were done with different interfaces. A couple of M-Audio's & another I can't recall. As far as I can tell, they all sound relatively the same. The GP-10 does sound brighter than the other interfaces, but now that I think about it, Boss pedals usually do seem to have a lot of presence. It sounds great, but it seems to be an exception to the standard. It's clear the Duet is a little brighter than the 16x08, but nowhere near as much as that GP-10. I'm glad you made this thread, because I never paid attention to the differences in Hi-Z's before. I always assumed they were uniform.

I made that video with my graphics card's desktop capture feature in Nvidia Geforce Experience. Then I had to import the video into Cakewalk to (roughly) sync the audio to the vid.

 

[cripple9]

BTW, I'm pretty sure you could play a full range audio recording into a reamp box (which converts a line-level signal to instrument-level), and then play that back into the audio interfaces' instrument inputs. Then you could look for freq discrepancies between them. If I can get my hands on a decent quality reamp box & a couple more interfaces, I'll give it a shot.

 

[el touristo]

Idk about a box that creates the same 'loading'/impedance/electrical 'character' signal as a guitar, but I could be ignorant about that. It would take some deep science for me to be convinced. Because I am both not so expert at that but I also know electricity is super counter-intuitive and 'weird'. I've never heard of something that 'records' the signal of a guitar exactly 'as is'. What we record is and amplified signal of guitars. The way guitar level preamps vary seems to be proof of that. As soon as you amplify it I think you've changed it more than just 'amplifying' it. Of course I could be completely wrong and can't predict the odds of that, lol. I do better to err on the side of uncertainty because it's so easy to be 'too sure' and then turn out that sureness was some kind of assumption etc. I can probably read and learn some deeper stuff about it. For my recording purposes I would not state my impression the way you did: "It's clear the Duet is a little brighter than the 16x08, but nowhere near as much as that GP-10. " I've listened to the recording several times, I could listen again. But it seems to me the Duet and the GP-10 are much closer to the same tone and both much farther from the 16x08 than they are from each other. I had said so previously, when I commented that I felt the difference between those two other units was 'normal' and the difference between them and the Tascam was aberrant. There must be some knowable electrical reason for all that. But getting to the bottom of that I think would require analysis by a specialist with special tools and understanding of circuit and guitar pickup behavior. I guess maybe if there is a thorough comparison review of direct boxes out there somewhere that might provide some insight, for example. I wish I had one to compare using it on a mic input on the 16x08 vs using and instrument input, I may pick one up for that purpose idk. I'd also like to be able to convert line live to mic so that the mic inputs on the Tascam can sometimes be used as line inputs. I have a couple of passive simple ones for that but idk if that is ideal: https://www.amazon.com/Hosa-GXJ-235-TRS-XLR3M-Adaptor/dp/B000068O4E

 

[el touristo]

A Radial J-48 cost almost as much as a Tascam 16x08 ! Makes me wonder if maybe the Tascam sound like it does because of lower internal voltage/cost. I don't mind, but I wish if that's true that Tascam would give some kind of description of 'what to expect' from these inputs and what their limits are, in terms of what sort of 'instrument' exactly they might sound 'normal' on and what conditions might leave you feeling you not getting a 'normal' result. Maybe there would be some way of determining that. I haven't heard back from Tascam yet, but it hasn't been very long. Like for example maybe the 'instrument' setting is ok for ACTIVE outputs, but not not passive, or not passive below certain spec of output or something like that. IDK what's going on.

 

[el touristo]

My 16x08 has a troublesome behavior when trying to use the mixer sliders. When you click on the slider to grab it, when you go to move it all it jumps to the highest position ! and then you can drag it to where you want to end up! It's helps to drag downwards firmly instantly as/after you click it. But the level jumping up it still makes an outburst, all you can do is shorten the time of that. Also you lose visual reference to where the slider had been...but there is a decent simple DB number at the bottom. It would great if you could just type in there, but that's not necessarily expected. It the level jumping that is a real issue. It's definitely in the 'not normal or acceptable' camp IMO. Maybe they can fix that with and update. Maybe more of us should bring it up. I'm all for getting that fixed.

 

[-mjk-]

https://www.prosoundweb.com/topics/studio/in_the_studio_understanding_applying_reamping/

 

[el touristo]

On the plus side, I think I can use the simple connector adapters I have, or maybe some XLR to 1/4 cables I may get, to use the mic inputs as line inputs. When I test with these adapter, it seems putting the gain knob all the way to the left is very close to the same as a -10 line input.
I sent half of a stereo signal (of a mono synth steady tone) to one of those -10 inputs, and the other half to the mic input through the simple connector adapter. I panned them left and right in the Tascam mixer. I would say actually the same. When the dB numbers at the bottom of each channel were the same (set to same output level) the channel meters and the mains left and right were level and in headphones it sounded panned center and monophonic and no apparent phase issue. One very minor caveat, not really a thing, is that you must turn off phantom power for the mic inputs you are using this way because the way I'm doing it I get a slight hum with phantom on. But yeah of course 1-4 and 5-8 each have there one phantom switch so that great. I just have to remember to turn it off. I don't so much like the adapter I bought because there is no way to make that any shorter and it sorta sticks out. Gives the XLR jack a mechanical disadvantage, and my interface is mounted about knee height right now so I'm concerned then ends sticking could get bumped if left that way for prolonged time. Much better to use cables. I may even have a short pair somewhere I will check. I think the question is why did they not just go ahead and use combo jacks. They didn't have to be claiming they were actually mic-pre-bypass. It would still be cool to just do what I'm doing without having to use special cables etc.
I think maybe they could consider that sort of thing even for the type of inputs circiuts these are. Because as far as I can tell them seem to be able to accept line level without and noticeable issue. Might as well do that and say they accept line, I be curious as to 'why not?'.

 

[cripple9]

My 16x08 has a troublesome behavior when trying to use the mixer sliders. When you click on the slider to grab it, when you go to move it all it jumps to the highest position ! and then you can drag it to where you want to end up! It's helps to drag downwards firmly instantly as/after you click it. But the level jumping up it still makes an outburst, all you can do is shorten the time of that. Also you lose visual reference to where the slider had been...but there is a decent simple DB number at the bottom. It would great if you could just type in there, but that's not necessarily expected. It the level jumping that is a real issue. It's definitely in the 'not normal or acceptable' camp IMO. Maybe they can fix that with and update. Maybe more of us should bring it up. I'm all for getting that fixed.

Weird, my faders seem to work fine. If I double-click the faders or effects knobs, they snap to unity (0dB), but that's the intended behavior. There's no other issues with it that I can find.

 

[cripple9]

I have a cheap Behringer Ultra-DI DI600P that I occasionally use for bass guitars, but there's a difference between a DI box & an actual reamp box. You can kind of reamp with some DI boxes in reverse, but you have to lower the input to the DI quite a bit & the results are pretty terrible. Long story short, a reamp box does the proper padding, etc. so you don't need to worry too much about impedance/levels.

https://www.radialeng.com/reamp-basics

https://www.amazon.com/s?k=reamp box

https://www.prosoundweb.com/in-the-studio-understanding-applying-reamping/

The link @-mjk- linked to was broken for me so I fixed it (Thanks BTW):

https://www.prosoundweb.com/topics/studio/in_the_studio_understanding_applying_reamping/

Nothin beats a good DI box for plugging an instrument into an XLR, but if you want to go the cheap adapter route, I think instead of what you linked to earlier (Hosa GXJ-235), you need an actual impedance transformer (Hosa MIT-129):

https://www.amazon.com/Hosa-MIT-129-XLR3M-Impedance-Transformer/dp/B000068O6A

Then you could just use a normal XLR M-F cable to extend it a little, so you don't have to worry about breaking it off in the interface. I would still keep the cables as short as possible though.
(EDIT): I also would assume you shouldn't use phantom power with a guitar plugged in to XLRs at all.

Anyway, I would think going through a mic preamp would color the sound more than a Hi-Z. That's why I'd like to find a way to test the Hi-Z ranges of different interfaces. You always see companies bragging about the quality of their mic preamps, but you don't hear anything about instrument input quality. If there really is a wide variance with audio interfaces in general, it would be awesome if someone could test a bunch of em & start a database we could all reference before we take the plunge on a new one. I definitely can't afford to do that myself, but it would be nice. I understand a lot of people just want their guitar to sound better. I'm less interested in knowing if an interface can "faithfully reproduce a true guitar sound" and more interested in seeing if Hi-Z sound quality varies from device to device. Some people use more wide ranged instruments through those inputs, so it couldn't hurt to use a full range reference source to see if the Hi-Z inputs cut or boost any frequencies.

 

[-mjk-]

The link @@-mjk- linked to was broken for me so I fixed it (Thanks BTW):

Thank you.

 

[el touristo]

yeah thanks I'd read about DI that has reamp feature. Point of clarity...I was saying the Mic inputs on the Tascam can be used for LINE level signal (I didn't test for guitar) with a simple cable or simple connector adapter with no pad or electronics. The lowest can setting is the same as an actual line input on the unit at -10 setting on those switches that select between -10 and +4. No you can use the mic inputs that way for a +4 signal. But for -10 it works fine. So I said Tascam should just put combo jacks on there anyway since the electronics work as -10 line inputs with gain control is all the way down. You know I didn't try it on guitar yet I guess I will I bet the impedance is off but no harm in trying. Yes my sliders jump to unity with a SINGLE click is very annoying. Also If I close the mixer window and reopen it it reverts to an unsaved state and the mains are set to +6 instead of 0 and any settings I made are lost. Also the scene memory thing won't work for me at all. I can't get any of the reamp articles links to work. They all say "
Oops! That page can’t be found.
It looks like nothing was found at this location. Maybe try one of the links below or a search? "

Thanks.