blorg t1_j67pnq6 wrote on January 28, 2023 at 8:51 AM

Reply to comment by abhikkp in These are not the same by disco_g

> The TC44C is an extremely bassy unit

It measures completely flat in terms of frequency response. That particular reviewer, he's just measuring with a sound card, and the slight roll off in the bass (and the larger roll off the other end) is very likely the input on that rather than the TC44C but it's enough to show it's NOT "extremely bassy".

ASR measured the TC44B which as far as I can make out is basically the same dongle in a different form factor, and with 2.5+4.4 rather than 3.5+4.4. Both use the same dual CS43131 chips. He doesn't have a linearity measurement, but he said he doesn't include these in reviews any more if the device is perfectly linear, as most are. So presumably this was for him as well.

I have the TC44B myself, and if I measure it, it is totally linear. It sounds linear as well, it is not "bassy". It's totally flat.

I can entertain at least some debate over the sound differences between these things. But specific stuff like this, where there is a specific significant tonal difference alleged, like it's "extremely bassy" - that can be measured. And it's not, it's just not.

One thing to bear in mind though with Symphonium is they are extremely low impedance, extremely low sensitivity and extremely source picky, possibly due to a combination of the low impedance and the way they implement their crossovers. They are very atypical on this point. I have the Helios (8.5Ω), and it actually doesn't sound good on the TC44B, it gets distortion and clicks and pops. It had some extremely weird almost "digital" behaviour, where it would cut out at an exact frequency and volume level, I don't think it's still doing this but when it was, it was something like a 47Hz tone, specifically, at a specific volume, it would just cut out entirely. 46Hz fine, 48Hz fine, and change the volume by one click and it was fine too. Really weird behaviour. But this is literally the only IEM I have, out of maybe 100, that is picky like this, and the TC44B isn't the only source it's problematic on, it's problematic on other sources as well, it's more the exception that I have like one dongle (E1DA 9038S) it's decent on. it's really more an issue with the way Symphonium make their IEMs than the dongle I think. So just I wouldn't use a Symphonium IEM as an example here, I could imagine the Meteor does something weird with the TC44C too, but I'd say that's on the IEM not the dongle. The Helios is the ONLY IEM I have that I hear major differences between sources, and it's because the IEM is weird.

wankthisway t1_j67qib4 wrote on January 28, 2023 at 9:03 AM

I'm betting what happens is plain old volume mismatching. Even a slight bump in loudness can make something feel "more detailed" or "bassier."

abhikkp t1_j68wsmz wrote on January 28, 2023 at 4:19 PM

That’s all good to know! That said, I absolutely can hear a difference between the Apple Dongle and and the TC44C on my Nios as well in terms of bass response. 64 Audio Units are built to not be source picky, and I’ve found that’s generally true in most instances. For example, there is very little difference between the sound out of my Ferrum Erco and the Apple Dongle for my Nios. However there’s definitely an audible mid-bass boost at comparable volume levels between the TC44C and the Apple Dongle. Ditto when using my Burson Playmate 2 with OpAmp upgrades.

For detail retrieval, however, I do agree that I can’t hear any extra details between these sources, though some (like the Erco) provide better imaging capabilities than the others, which does make perceived detail better. Anyways, I’d encourage everyone reading to try out these sources and IEMs themselves before coming to conclusions…looks like you have the cousins of both of my devices, but I don’t think that’s a proper substitute for in-person A/B testing with the exact same ones.

blorg t1_j696zd2 wrote on January 28, 2023 at 5:28 PM

There are two possibilities here, either this is in your head, or you have a faulty unit.

Here's some measurements of my ddHifi TC44B vs the Moondrop MoonRiver 2, using an IEM. I used the 64 Audio Tia Trio, which is the closest I have to your Nio. It also has the Linear Impedance Design to sound the same, and it also similar very low impedance (5.5Ω Trio, 6Ω Nio).

https://imgur.com/a/oLtg0yu

There are actually two lines on that graph, although you might have to look very closely to see that. There is NO variance in the frequency response.

Like I said, I have something of an open mind on discussion on stuff sounding different. There are various ways things could possibly sound different. But this dongle is not "extremely bassy". It is entirely flat and does not change the tonal characteristics of the headphone at all, in any way.

abhikkp t1_j6989e9 wrote on January 28, 2023 at 5:37 PM

I appreciate all of your graphs! Lots to ponder and think on. I will note, it’s not just my head as I’ve had several friends and family A/B my units as well and they’ve also noticed a difference — without any priming. Also, again, the device you’re measuring is different from my own…there’s a possibility that the implementation of the 44C’s identical chipset is very different from the 44B.

Moreover, at a certain point, I think these graphs fail to capture audible differences between different amps. I am a scientist by trade, so I do appreciate the seeming objectivity that these graphs provide and I’m also wary that I’m susceptible to placebo effect. However, from my own experience with the hobby thus far, I think there’s no substitute for trying devices out yourself!

As an aside, do you happen to have measurements of the Cayin RU6 on hand? I’m curious if that measures any differently as it’s R2R and not delta sigma!

blorg t1_j69d6ie wrote on January 28, 2023 at 6:10 PM

There are other measurements, like I linked in the first post, showing the TC44C is entirely linear and has no bass boost. I'm just doing this measurement again with an actual IEM in there (from the same company and of similar impedance to yours) in case it could be something like the effect of output impedance on the impedance curve of the headphone- although in this case the output impedance of the dongles is both extremely low, and 64 Audio as you say yourself has their LID technology with very flat impedance curves.

I'm open to there being certain differences, or interactions... like I said I have issues with the Helios on the TC44B, although I'd blame the Helios for that.

I just object to people characterizing stuff like a DAC/amp that measures entirely flat in frequency response as being "extremely bassy". It's just not. "Extremely bassy" is frequency response and it's measurable, and it's not there. Maybe there is something else that doesn't come up... but a tonal difference like that will be there in the frequency response.

One thing that sometimes can happen to cause this, is if you have some setting that is different between the two devices, like you have a bass boost APO attached to the TC44C, but not to the other devices. That is exactly the sort of thing that could cause this.

I don't have the Cayin RU6. Wolf/L7, Archimago and SBAF have measurements though. It doesn't measure well objectively. Archimago liked it though, or at least appreciated it wasn't trying to be high fidelity but was a device "with character" aiming for a certain type of sound. The others, not so much.

abhikkp t1_j69eyjx wrote on January 28, 2023 at 6:22 PM

Very much appreciate how cordial this interaction has been :)

I will read through all of this! On your note about APO -- I don't use any onboard software EQ.

Finally, I have used my IEMs with the iFi Gryphon as well, which has a Burr-Brown chip and is supposed to be "warmer" than other devices but I found literally no difference between the Gryphon and the Apple Dongle in sound quality or frequency response. And even the Gryphon sounds less bassy than my TC44C unless I enable Gryphon's bass boost. Maybe it's just the interaction between my TC44C and my IEMs but that's what I've found in my daily use case.

Nonetheless, clearly, you have a ton of personal experience in the hobby, so I will absolutely respect your expertise and opinion on this matter. I just think my anecdotal experience is also worth sharing!

blorg t1_j69n06x wrote on January 28, 2023 at 7:16 PM

It's not that you'd be deliberately using some sort of software EQ. Rather that some audio "enhancement" (and a bass boost is one of the stock Windows enhancements) got attached to the TC44C but didn't get attached to the others.

If you literally don't hear any tonal difference across a wide range of other different devices, but hear a really distinct one on the TC44C- this really indicates that there is something messing with the sound on that one. Particularly as no other subjective review of the TC44C seems to find it "extremely bassy", they use words like neutral, flat, clean, accurate, transparent, the most I found was one review in the other direction, going with mostly neutral but "slightly bright".

You could measure it yourself, download REW and just do a tone sweep with it and record it, do the same with another DAC to make sure any variance isn't the recording device. If you do do this, don't use exclusive mode, this will ensure it goes through whatever you normally have going on. You'll either see this dramatic difference in the measurement, or you won't.

If you do- it confirms you were hearing something real. I'd suspect if it is there, it's a configuration issue. It's also possible it will measure entirely flat. Either way it's another data point, you can interpret it as you like. If I had ONE thing that sounded radically different than everything else, that sounded the same- I'd wonder why.