Monoprice M1570C Headphone Review

[isostasy]

On Oratory's website there's only mention of M1570 which I'm currently assuming is the open version (not the closed version) - but modifying the closed back to an open version I don't think you can assume will measure the same as the purchased open backed version. In order for you to assume your open backed mod would measure the same as the bought open backed version was that if you bought an identical open backed "earcup plate" to attach to the back and as long as you knew for sure everything else between the two models of headphones was the same - I'm not sure anybody knows that's the case? But, but, but, if you know the only change is the closed back versus the open back then that's ok, but of course you'd still need to purchase the genuine open back plate.......and how do you know for sure that's the only change between the two models?

EDIT: @mr.at has just said in his post above mine that they're using different drivers for a start, so you certainly can't assume that replacing the closed back with an open back as a mod will result in the same frequency response as the open version - it won't. So it seems like the most valid thing to do is still to measure the effect of the mod, as we don't what that effect is currently.

What's his website, you mean the reddit index? He's measured the M1060, M1570, M350 planar, M650, and Modern Retro.

Yes, this is what I said originally. I certainly do not 'assume [they] will measure the same', and if you read back over what I wrote you will see I already said what you then go onto say:

'If the M1060C is literally just a M1060 with closed cups then removing the backs would be a legitimate mod' (added emphasis). I'm not sure how this could be clearer, unless you thought I was using 'literally' in the ironic non-literal sense some people do? (e.g., you're literally jumping down my throat).

'if it's a clear cut case of the same headphone with and without a closed back'

Just to make sure, I then say this still can't be assumed even if it were true for one model:

'it doesn't necessarily follow that this is also true of the other Monoprice models'

@mr.at does then go onto say they're different drivers in response to my hypothetical statement above. This seemed like perfectly reasonable discussion... I suggested it could be feasible 'if' they are 'literally' 'the same' other than the back, mr.at says ah no they're not, ok great that's answered the hypothesis. I can't go back in time and already know mr.at would tell me the drivers are different before he does, before I wrote my post...

 

[Robbo99999]

I like the EQ/PEQ route a lot: it is free, educational, and… humbling—what differences you can and can’t hear! But is it contingent upon having a low/very low distortion headphone such as this M1570C? There is also the ~10% non-FR-related stuff (reflections, resonances, damping, etc.): is this where you may experiment with physical mods?

In my experience, the overall soundstage potential of a headphone will remain the same for a particular model of headphone, and then EQ is about making the tonality and bass & other elements equal & balanced so that you can enjoy all the various elements within the music, with the easiest most obvious effect being EQ'ing up the bass in a open backed headphone that has deficient bass (most of the time) so that now you can follow the bass line of the music properly & with great definition if it's a low enough distortion headphone in the bass. I agree with you on the EQ/PEQ front, it's just such a great tool & is truly transformative - EQ just loves headphones! The 10% non-FR stuff you mention I will go along with you on that & say that is the soundstage element of the headphone, but that's about where I'll stop as I think measured frequency response & distortion measurements cover everything else, and I don't really think physical mods come into play in that aspect (the 10% aspect).

 

[Robbo99999]

What's his website, you mean the reddit index? He's measured the M1060, M1570, M350 planar, M650, and Modern Retro.

Yes, this is what I said originally. I certainly do not 'assume [they] will measure the same', and if you read back over what I wrote you will see I already said what you then go onto say:

'If the M1060C is literally just a M1060 with closed cups then removing the backs would be a legitimate mod' (added emphasis). I'm not sure how this could be clearer, unless you thought I was using 'literally' in the ironic non-literal sense some people do? (e.g., you're literally jumping down my throat).

'if it's a clear cut case of the same headphone with and without a closed back'

Just to make sure, I then say this still can't be assumed even if it were true for one model:

'it doesn't necessarily follow that this is also true of the other Monoprice models'

@mr.at does then go onto say they're different drivers in response to my hypothetical statement above. This seemed like perfectly reasonable discussion... I suggested it could be feasible 'if' they are 'literally' 'the same' other than the back, mr.at says ah no they're not, ok great that's answered the hypothesis. I can't go back in time and already know mr.at would tell me the drivers are different before he does, before I wrote my post...

Sorry, I really don't know how to digest this post, it's quite confused, but I know you're a good guy generally! To be succinct & to cut out the BS then it seems we can easily say that there's no guarantee that a closed back M1570C modded to an open backed M1570 would sound the same given what a few of us have discussed and that one user has said that the drivers are different for a start - I don't think there's much else to say. (It doesn't matter if you've been wrong in your post, I'm not "jumping down your throat", we're having a discussion about headphone mods).

 

[isostasy]

Sorry, I really don't know how to digest this post, it's quite confused, but I know you're a good guy generally! To be succinct & to cut out the BS then it seems we can easily say that there's no guarantee that a closed back M1570C modded to an open backed M1570 would sound the same given what a few of us have discussed and that one user has said that the drivers are different for a start - I don't think there's much else to say. (It doesn't matter if you've been wrong in your post, I'm not "jumping down your throat", we're having a discussion about headphone mods).

You still haven't read the previous posts properly! @mr.at said the m1060 and m1060c have different drivers, the jury is still out whether the m1570 and m1570c have the same drivers. And I still never said I 'guarantee that a closed back M1570C modded to an open backed M1570 would sound the same'!

All I said was 'If the [headphone] is literally just [the same headphone] with closed cups then removing the backs would be a legitimate mod'. You can't disagree with me on this?

I'm with you that generally you need to measure whenever you make mods (I have my own mics and post measurements from them on ASR regularly). But if it was proven that headphone A was exactly the same as headphone B apart from the closed back then I don't see why someone couldn't just remove the back to turn one into the other. Before you misunderstand me again, I'm NOT saying this is the case here, just that in a hypothetical situation as I've just stated, it MIGHT be. This is still no different to what I put in my first post, which I had intended to be helpful and pretty unambiguous.

 

[Robbo99999]

You still haven't read the previous posts properly! @mr.at said the m1060 and m1060c have different drivers, the jury is still out whether the m1570 and m1570c have the same drivers. And I still never said I 'guarantee that a closed back M1570C modded to an open backed M1570 would sound the same'!

All I said was 'If the [headphone] is literally just [the same headphone] with closed cups then removing the backs would be a legitimate mod'. You can't disagree with me on this?

I'm with you that generally you need to measure whenever you make mods (I have my own mics and post measurements from them on ASR regularly). But if it was proven that headphone A was exactly the same as headphone B apart from the closed back then I don't see why someone couldn't just remove the back to turn one into the other. Before you misunderstand me again, I'm NOT saying this is the case here, just that in a hypothetical situation as I've just stated, it MIGHT be. This is still no different to what I put in my first post, which I had intended to be helpful and pretty unambiguous.

Ah, ok, I hadn't noticed the fact that we were talking about a different headphone, God knows why we're talking about the m1060 & m1060c when the review is about the M1570C, sorry I hadn't noticed that difference! Well, that was a bit of a waste of time! Well, we agree, measure the mods. Job done - you can't assume anything unless you have the facts!

 

[Dazerdoreal]

Considering the Audeze-LCD-XC has a golfing panther I am a bit surprised about the headless rating. The frequency response is similar and the distortion rating is not that good but still far from bad. Looks like a slightly worse but way cheaper budget LCD-XC to me. I know you dont count in pricing but I'd still say this is at least "not terrible".

Audeze LCD-XC Review (Closed-back Headphone)

This is a review and detailed measurements of the Audeze LCD-XC (late 2021 edition). It was sent to me by the company and costs either US $1,299 or $1,799 depending on accessories. The LCD-XC feels quite sturdy and solidly built. Alas, it is also the heavies headphone I have measured: The...

www.audiosciencereview.com

 

[CedarX]

Considering the Audeze-LCD-XC has a golfing panther I am a bit surprised about the headless rating. The frequency response is similar and the distortion rating is not that good but still far from bad. Looks like a slightly worse but way cheaper budget LCD-XC to me. I know you dont count in pricing but I'd still say this is at least "not terrible".

The headless panther is Amir’s (subjective) assessment of objective (but approximate) measurements and listening tests. Sure, it’s debatable… However, the LCD-XC is closer to the target on a much wider freq. range than the M1570C and it does not have these pesky distortion resonances right where you don’t want them—where our ear is the most sensitive. Then there is the FR roughness with the faux-leather pads, the large response difference with the velour pads (a sign of inconsistent results?), and, per Amir, a questionable comfort. So headless it is… but I agree, a lenient “not terrible” rating may be appropriate.

 

[Zensō]

The headband and yoke are a straight up copy of Focal.

 

[SmackDaddies]

I tended to give the same vote initially, but then three aspects made me switch to "headless":

1. Any headphone you won't bear on your head for a longer time is useless.
2. Low distortion is "not an Art" when bass is barely present.
3. Better and cheaper offers exist.

100%, in particular #1

 

[Maiky76]

This is a review, listening tests and detailed measurements of the Monoprice Monolith M1570C closed back planar magnetic headphone. It is on kind loan from a member and costs US $600 although I am told it goes on sale for just $200!
View attachment 294350
This is a large and heavy headphone. The owner sent it with the faux leather pads which made it gigantic width wise. With velour pads, it is much more manageable and it initially fit well on my head. After a few minutes though, the headband started to dig into my head so not sure I could wear it for more than half hour to an hour.

Note: The measurements you are about to see are made using a standardized Gras 45C. Headphone measurements by definition are approximate and variable so don't be surprised if other measurements even if performed with the same fixtures as mine, differ in end results. Protocols vary such as headband pressure and averaging (which I don't do). As you will see, I confirm the approximate accuracy of the measurements using Equalization and listening tests. Ultimately headphone measurements are less exact than speakers mostly in bass and above a few kilohertz so keep that in mind as you read these tests. If you think you have an exact idea of a headphone performance, you are likely wrong!

Fitment on the fixture was relative easy but there was an issue as you see below.

Monoprice Monolith M1570C Measurements
I started the measurements with the faux leather pads. That unfortunately has a deep hole right at the frequency that I calibrate to 94 dBSPL. It looked very odd that way so I broke my normal rule and brought the overall level to get compliance elsewhere:
View attachment 294351
The graph is very rough which typically indicates resonances (more on this later). I decided to switch to Velour pads which is shown in dashed brown. FYI, swapping pads was a royal pain as you have to insert a flexible lip into a very narrow slit all around the cup. Good thing I don't curse as there would have been plenty of that otherwise!

Anyway, the velour pad seemed more workable to me so let's go with that from here on:
View attachment 294353

At least now we are just short of bass and midrange as opposed to the uneven response of leatherette. Here is our relative curve for the much needed equalization:
View attachment 294354

Fortunately distortion is extremely low, sans some resonances:
View attachment 294355

The resonances were milder with the leather pad which may indicate it is the case resonance.
View attachment 294356

Group delay has a number of pronounced discontinuities which is likely partially generated by above resonances:
View attachment 294359

Impedance is relative low and flat as is typically the case with planar magnetic headphones:
View attachment 294357

Sensitivity is below average so you need some amplification:
View attachment 294358

Monoprice M1570C Listening Tests and EQ
Immediate impression was: "where is the bass?" So out came the EQ:
View attachment 294360

As you see, I just tried to compensate for lack of bass and midrange. Due to high amount of bass boost, you have to allow a lot of headroom. Above was good enough for my test tracks which includes some with very deep subbass. You lose fair bit of headroom because of this so best to have a powerful headphone amplifier. My RME ADI-2 Pro drove it with ease though.

With EQ, we now have very good bass with nice fidelity. Spatial qualities were also very good and pleasing in the way instruments were separated around my ears. I thought at times the highs were a bit unpleasant but it could be me being biased by the measurements. I tried a couple of sharp filters where the resonances are but that changed tonality too much to conclude that distortion was being reduced.

Conclusions
The Monoprice M1570C seems like a "phoned in" design to me. There is clearly no performance target as far as tonality. Likely specs were given at high level of manufacturer in far east and out come a heavy headphone with very odd frequency response. The saving grace is very low distortion courtesy of large drivers allowing EQ to correct many of its ills. If it does indeed go on sale for $200, and you can tolerate its weight, it may not be a bad option.

I can't recommend the Monoprice Monolith M1570C as is. With strong EQ, it does wake up and produce good fidelity. So with that, I can recommend it especially at at the $200 price point. Just don't try to change the pads if you are not in perfectly calm mood.....

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As always, questions, comments, recommendations, etc. are welcome.

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Here are some thoughts about the EQ.


Notes about the EQ design:

• The average L/R is used to calculate the score.
• The resolution is 12 points per octave interpolated from the raw data (provided by @amirm)
• A Genetic Algorithm is used to optimize the EQ.
• The EQ Score is designed to MAXIMIZE the Score WHILE fitting the Harman target curve (and other constrains) with a fixed complexity.
  This will avoid weird results if one only optimizes for the Score.
  It will probably flatten the Error regression doing so, the tonal balance should be therefore more neutral.
• The EQs are starting point and may require tuning (certainly at LF and maybe at HF).
• The range around and above 10kHz is usually not EQed unless smooth enough to do so.
• I am using PEQ (PK) as from my experience the definition is more consistent across different DSP/platform implementations than shelves.
• With some HP/amp combo, the boosts and preamp gain (loss of Dynamic range) need to be carefully considered to avoid issues with, amongst other things, too low a Max SPL or damaging your device. You have beed warned.
• Not all units of the same product are made equal. The EQ is based on the measurements of a single unit. YMMV with regards to the very unit you are trying this EQ on.
• I sometimes use variations of the Harman curve for some reasons. See rational here: https://www.audiosciencereview.com/...pro-review-headphone.28244/page-5#post-989169
• https://www.audiosciencereview.com/...pro-review-headphone.28244/page-6#post-992119
• NOTE: the score then calculated is not comparable to the scores derived from the default Harman target curve if not otherwise noted.

Good L/R match.
Tuned to diffuse field or HD800 type of response?

Score no EQ: 54.9
Score Amirm: 90.8
Score with EQ: 97.3

I have generated one EQ, the APO config file is attached.

Monoprice M1570C Velour pads APO Score Full EQ Flat@HF 96000Hz
July172023-143102

Preamp: -12.1 dB

Filter 1: ON PK Fc 29.94 Hz Gain 2.30 dB Q 0.87
Filter 2: ON PK Fc 20.86 Hz Gain 9.89 dB Q 0.16
Filter 3: ON PK Fc 436.58 Hz Gain 3.54 dB Q 1.11
Filter 4: ON PK Fc 2979.32 Hz Gain -0.58 dB Q 5.85
Filter 5: ON PK Fc 7294.87 Hz Gain 5.57 dB Q 2.21
Filter 6: ON PK Fc 8428.01 Hz Gain -5.35 dB Q 5.99