[jude]

Maybe my eyes are deceiving me, but in what way are the treble of the APM uncannily similar to the HD800S based on Jude's graphs? Their peaks and dips are in different places, starting at the 3.5kHz region. Maybe I'm not seeing something you're seeing?

Perhaps he meant the HD650. If you isolate a select section one might see similarities (in that section). For example:

As I said in my previous post, though, the only way to compare headphone frequency responses is (in my opinion) in their entireties.

 

[jude]

Thanks for the work, Jude. I really welcome another set of measurements done with another methodology / test fixture than the ones we commonly see.
It's always a little difficult to know which frequency would be quite the most representative for matching FR curves and how that intersect with how loud we'd set the HP levels when subjectively trying to "match" them...

Yes, normalizing for comparison can be a bit of a pain point. We've been experimenting with ways to set levels that make for better comparisons -- we'll see how that pans out, and will post results if anything useful comes from it.

...I've spent quite a bit of time and money in 2020 trying a lot of the ANC BT usual suspects and some of them sounded to me in a way that some measurements didn't quite represent well, so while it's entirely possible that it's just how they interacted with my anatomy that caused these divergences I'm still quite curious how they'll measure on a 5128.

Of course, no measurement fixture (not even the 5128) is going to perfectly represent any one of us, but at least the 5128 is simulating a human average across the entire audio range (versus 100 Hz to 10 kHz at the 711 simulator's reference plane). When we post the 5128 measurements of those other ANC BT headphones next week, let's see if they hit any closer to home for you.

 

[Heyyoudvd]

I might have missed it but has there been any confirmation as to whether plugging in the APM has any effect?

I know that will decrease the latency, but I’ve seen opposing claims and no concrete answer regarding whether using the 3.5mm will make a difference in sound quality as compared to Bluetooth.

Has there been any confirmation one way or the other?

 

[Karnicopia]

I ended up switching back to balanced. I think my audiogram has a peak in the midrange which makes sense since our ears are tuned for the vocal range so my audiogram put in a midrange dip so I think the balanced with my hearing probably creates a midrange bump which I like. Vocal added a little too much zip in the midrange so balanced it is. It would be kind of cool to see FR plots of the different presets maybe default, balanced, vocal and bright just to see what the DSP is doing.

 

[fabripav]

I’m surprised no one has directly compared the APM with the Hifiman Deva.

 

[Ilomaenkimi]

Let's start with two popular, very well known Sennheiser models, the Sennheiser HD650 and the Sennheiser HD800S. First, let's look at those individually as measured on the Brüel & Kjær 5128:

---

Fig.1 (above): Sennheiser HD650 frequency response, average of four seatings.

---

Fig.2 (above): Sennheiser HD800S frequency response, average of four seatings.

---

NOTE: For both the Sennheiser HD650 and Sennheiser HD800S measurements above, neither has been used for personal listening -- they've only been worn by measurement fixtures. As a result, the earpads on both are like new.

---

Comparing such very different headphones can be tricky, so I'm showing at least two normalization points for each of these Sennheiser headphones in comparison to the Apple AirPods Max. Following are comparisons of the Apple AirPods Max's frequency response to the Sennheiser HD650 and HD800S:

---

Fig.3 (above): Apple AirPods Max and Sennheiser HD650 frequency responses compared, normalized at 500 Hz, 1/12 octave smoothing.


Fig.4 (above): Apple AirPods Max and Sennheiser HD650 frequency responses compared, normalized at 1 kHz, 1/12 octave smoothing.


Fig.5 (above): Apple AirPods Max and Sennheiser HD650 frequency responses compared, normalized at 2 kHz, 1/12 octave smoothing.

---

Fig.6 (above): Apple AirPods Max and Sennheiser HD800S frequency responses compared, normalized at 500 Hz, 1/12 octave smoothing.


Fig.7 (above): Apple AirPods Max and Sennheiser HD800S frequency responses compared, normalized at 1 kHz, 1/12 octave smoothing.

---

NOTE: I almost chose not to include the comparison in Fig.4 because the HD650 notch at 1 kHz pushes its curve down in the comparison. Without the notch at 1 kHz, it would look rather like the overlay in Fig.3. I included Fig.4 just to help avoid confusion as to its absence. Also, while I don't usually normalize at 2 kHz, I did that for Fig.5, just in case you were curious about a comparison that lines up the treble response more.

---

The measurements in this post were made using:

• Brüel & Kjær High-frequency Head and Torso Simulator (HATS) Type 5128
• Audio Precision APx555 Audio Analyzer (with Bluetooth Duo Module)
• Audio Precision APx1701 Transducer Test Interface
• Herzan custom-designed acoustic & vibration isolation enclosurez

---

Can you compare APP and APM frequency responses same way?

 

[tinyman392]

I might have missed it but has there been any confirmation as to whether plugging in the APM has any effect?

I know that will decrease the latency, but I’ve seen opposing claims and no concrete answer regarding whether using the 3.5mm will make a difference in sound quality as compared to Bluetooth.

Has there been any confirmation one way or the other?

You’d technically be double amping the headphones, so the answer is a definite yes, you’d be changing the sound quality of the headphones. Whether that’s a positive change or not would entirely depend to the DAC/amp being used and how they respond with the APM. Some may also feel that the act of multiple audio conversions or double amping may automatically have a negative effect on sound quality, though I would feel like the signature change that some DACs/amps provide would probably be larger.

 

[SilverEars]

The treble similarity to the 800S is pretty uncanny and quite interesting.

I don't see similarity either. You can see rise to treble with 800S, but more of a sustain with APM. Also the overall tonal difference is APM has like most people are saying a V- shape, but 800S has a response that looks more like a step function in the treble. It just tells me how strongly treble tilted 800S is. This becomes apparent when switch to it from a warmer headphone since that 800S response looks cold. What I notice is that the definition is mainly in the treble. Which is not a surprise seeing the response.

Another difference is 2k. APM has a strong rise in 2k, but I don't hear this personally. Strong 2k usually cause high vocal defintion, but APM isn't all that resolving in the first place. I definately hear the treble, but the APM treble isn't tilted as much toward treble as the 800S.

Nice to see that 650 measurement for reference. It looks like what I expect of 650 response. Looking forward to seeing the other ANC headphones in the class.

For me the interesting comparison is with the 650. I prefer mids to be somewhat like the 650 and as a point of comparison, APM has a different mid response that cause more of V.

For people that has heard 800S and 650, both provide good references for comparison.

 

[DougD]

Let's start with two popular, very well known Sennheiser models, the Sennheiser HD650 and the Sennheiser HD800S. First, let's look at those individually as measured on the Brüel & Kjær 5128: << snip snip >>

Mr Jude !!! Your presence in a forum I'm paying attention to is unusual. And always welcome, of course.

I saw a comment about the APMs, by a well-respected guy ("Torq") with a lot of experience and investment in TOTL headphone gear, which I'll paraphrase, probably poorly, as "probably the first wireless headphones with good enough performance from an audiophile's perspective to be a serious contender as a disruptive, lifestyle-changing technology."

Is that why you're here? Are you sensing that we may have hit that threshold with wireless?

 

[tinyman392]

Mr Jude !!! Your presence in a forum I'm paying attention to is unusual. And always welcome, of course.

I saw a comment about the APMs, by a well-respected guy ("Torq") with a lot of experience and investment in TOTL headphone gear, which I'll paraphrase, probably poorly, as "probably the first wireless headphones with good enough performance from an audiophile's perspective to be a serious contender as a disruptive, lifestyle-changing technology."

Is that why you're here? Are you sensing that we may have hit that threshold with wireless?

Didn't HiFiMan release their Ananda as a BT headphone? I'm not sure how it is (I actually just purchased one hoping it's close enough to my HE-560 in SQ), but I'd assume that would have had good enough performance from an audiophile's perspective

 

[DougD]

Didn't HiFiMan release their Ananda as a BT headphone? I'm not sure how it is (I actually just purchased one hoping it's close enough to my HE-560 in SQ), but I'd assume that would have had good enough performance from an audiophile's perspective

I don't know. Wireless h/ps weren't on my radar screen until a week ago, BECAUSE I believed the SQ wasn't at a level I'd be happy with. (And I don't have a really strong use case, working from my home office during the pandemic.)

But if wireless cans are poised to take over the upper end of the mass market for (everyday) headphones, that may make it a bit tougher for the smaller companies in the traditional h/p ecosystem. Wireless brings in a whole bunch of new technologies that those designers/manufacturers don't necessarily have any expertise in, and they may lack the scale necessary to move up the learning curve.

It's what Confucius said: May you live in interesting times.

 

[tinyman392]

I don't know. Wireless h/ps weren't on my radar screen until a week ago, BECAUSE I believed the SQ wasn't at a level I'd be happy with. (And I don't have a really strong use case, working from my home office during the pandemic.)

But if wireless cans are poised to take over the upper end of the mass market for (everyday) headphones, that may make it a bit tougher for the smaller companies in the traditional h/p ecosystem. Wireless brings in a whole bunch of new technologies that those designers/manufacturers don't necessarily have any expertise in, and they may lack the scale necessary to move up the learning curve.

It's what Confucius said: May you live in interesting times.

A lot of them have already begun to delve into BT technology, and to be honest I'd say they're successful. Audeze (if you like their sound signature) has the Mobius (which is actually quite linear) and their BT Cipher cable for their iSine series. Etymotic has their new BT cable now for their ER series. NAD's HP70 reminds me a lot of the HP50 when I reviewed them eons ago, though their amplifier's volume is a little wonky (weird jumps as you increase volume, I think it goes from like 60 dB to 75-80 dB with one "click").

I haven't read up on how well received the Panda are on Head-Fi, but if you're a fan of the smoother/warmer Audeze sound it would work well there too (granted there are lots that don't like the laid-back signature). I feel like all of these offerings are more than good enough for BT headphones. Granted if the headphone's sound signature doesn't provide you what you're looking for, then it won't be good by any means.

I mentioned the HiFiMan Ananda BT above, but they also have a few TWS setups (the TWS600 wasn't taken too well for it's overly bright signature, I haven't heard or read up on the TWS1000) as well as a wireless module for their Deva headphone (someone was asking for a comparison with that and the APM, I feel like this comparison would actually be a very good one as the price range seems about right for where the APM would be throwing down from an audio quality perspective (granted it's on the higher side of the price range). Though besides the TWS600, I haven't heard any of HiFiMan's other BT offerings.

AKG has also offered some good BT offerings for nearly a decade as well. Many of which follow the Harman curve (their parent company kind of developed that target) and some are well received as well. I haven't heard any of their more recent offerings, only the AKG K845BT from like 5 years ago which was a go to of mine for portable use for quite some time.

I guess at the end of the day, you really can't know unless you actually try it. I know a lot of audiophiles that immediately just push away BT because it can't ever be audiophile material. I've kind of been against this for quite some time now. Pair in a decent portable DAC/amp with a good BT module to a good driver and you'll have a good BT headphone. They aren't all good, and some have their issues, but I've had my fair share of good BT headphones.

 

[fabripav]

I haven't heard or read up on the TWS1000) as well as a wireless module for their Deva headphone (someone was asking for a comparison with that and the APM, I feel like this comparison would actually be a very good one as the price range seems about right for where the APM would be throwing down from an audio quality perspective (granted it's on the higher side of the price range).

The DEVA pair I have were less than half of the price of the APM but I really wanna try them out...

 

[jude]

Can you compare APP and APM frequency responses same way?

@Ilomaenkimi, you were a bit ahead of me, as this was next, and here it is.

Let's start with the AirPods Pro alone, measured on the Brüel & Kjær 5128:

---

Fig.1 (above): Apple AirPods Pro frequency response, average of four seatings.

---

Now, as mentioned above, comparing choosing where to normalize for a comparison between two headphones can be tricky, so I've chosen three points: 500 Hz, 1 kHz, and 3 kHz (below):

---

Fig.2 (above): Apple AirPods Max and AirPods Pro frequency responses compared, normalized at 500 Hz, 1/12 octave smoothing.

Fig.3 (above): Apple AirPods Max and AirPods Pro frequency responses compared, normalized at 1 kHz, 1/12 octave smoothing.

Fig.4 (above): Apple AirPods Max and AirPods Pro frequency responses compared, normalized at 3 kHz, 1/12 octave smoothing.

---

NOTE: The Apple AirPods Pro was measured when brand new, using a pair that was issued subsequent to the AirPods Pro Service Program for Sound Issues.

We also measured this pair with a couple of kinds of foam eartips, and we'll post those separately later in the Head-Fi Audio Measurement Lab sub-forum.

---

The measurements in this post were made using:

• Brüel & Kjær High-frequency Head and Torso Simulator (HATS) Type 5128
• Audio Precision APx555 Audio Analyzer (with Bluetooth Duo Module)
• Audio Precision APx1701 Transducer Test Interface
• Herzan custom-designed acoustic & vibration isolation enclosure

---

 

[controlmajortom]

I don't see similarity either. You can see rise to treble with 800S, but more of a sustain with APM. Also the overall tonal difference is APM has like most people are saying a V- shape, but 800S has a response that looks more like a step function in the treble. It just tells me how strongly treble tilted 800S is. This becomes apparent when switch to it from a warmer headphone since that 800S response looks cold. What I notice is that the definition is mainly in the treble. Which is not a surprise seeing the response.

Another difference is 2k. APM has a strong rise in 2k, but I don't hear this personally. Strong 2k usually cause high vocal defintion, but APM isn't all that resolving in the first place. I definately hear the treble, but the APM treble isn't tilted as much toward treble as the 800S.

Nice to see that 650 measurement for reference. It looks like what I expect of 650 response. Looking forward to seeing the other ANC headphones in the class.

For me the interesting comparison is with the 650. I prefer mids to be somewhat like the 650 and as a point of comparison, APM has a different mid response that cause more of V.

For people that has heard 800S and 650, both provide good references for comparison.

I have all three and they don't sound similar to either. APM has a grainy quality to the treble that I associate with cheaper headphones. HD650 has better tonality but sounds duller/more rolled off. Not even going to bother comparing the APM treble with the HD800S.