[Philimon]

@OldDude04 or anyone, let me know if youre willing to sell or trade. Thank you

I do have a fittingly big head and a preference for ~3kHz dips so these might work for me. Would at least be fun to try.

 

[ngoshawk]

Pretty impressive on first listen. My first experience with this driver technology. It almost sounds like ba driver in iem: clean, fast, effortless, right decay. Good timbre though. Most impressed with vocal reproduction so far: spacious, limitless notes yet accurate and not creamy. Crossfeed on my ak class an abulous amp significantly improves the imaging on AMT.

Fabulous A&K CA1000 & case btw.

 

[Philimon]

First impressions aka unreliable aka I will not be held liable.:

TONAL
I like 3kHz dips... I can hear the 3kHz dip as slightly pushed-back vocals, but Im accustomed to such v-shape. In total, probably most resembles my T20RPmod but less warmth on AMT (a good thing).

TECHNICAL
Seemingly at least on level of HE6se, and potentially greater in every regard. The soundstage is large and deep (depth also reminds me of T20RPmod so could be partly a frequency response and pad depth thing). Large soundstage while still sounding lush and dense and without being diffuse or 2-dimensional, most impressive. I was expecting weaker bass than HE6se but it is not at all, just different tonal balance. Tonally highs are uneven, but imaging remains clear and very defined.

I like it a lot.

Will do fr measures and post more considered and detailed impressions later.

[equipment: Eitr > ModiMB 1.2 > Jot2 unbalanced]

Mono AMT is big but comfortable. Ive only used for a short session though.

 

[Philimon]

Monoprice AMT sounds like a clear tier above HE6se (modded) in every way aside from tonal balance. Tone is a highly subjective attribute in perception and preference anyway... AMT treble is laid-back tonally, however its speed and clear resolve of fine and low-level detail makes up for the tonal disparity and keeps you totally engaged. This reminds me why I wanted to get rid of vintage Stax Lambda in college, too distracting for studies.

And for the negative: does exhibit a little bit of bass bloom (air pressurization by my definition), a little less than that of Yamaha YH-1. This annoyance is partly mitigated by the unfortunate physical weight of the headphone, meaning I dont expect very long listening sessions more than an hour for Mono AMT. I just did an hour+ and decided it was time for a break for my ears and neck, however it was totally enthralling to hear new detail in music that Im very familiar with especially since the new details emerged from the full-range of bass-mids-highs. The weight strain can be compared to Audeze LCD-X, however LCD-X bass could never hit like this. For reference, HE6se has more bass impact than LCDX 2022, while LCDX 2022 is more resolving of microdetail than HE6se. AMT bests them both from my recollection (will work on final impressions and direct comparisons later).

I think the bass alone is worth price of admission. If weight and bass bloom were not a factor, then I would see AMT as a headphone to aspire to at MSRP. Despite those serious (to me) flaws, a keeper at $300.

An oddity is when attempting to measure on EARS. Not sure what to make of it but there is wide bass variance. Such variance is indicative of pad leak. Yes, the pads are huge and extend past the edges of the mic baffle but the pads are relatively supple so its hard to imagine a leak. idunno

All measures done on EARS, averaged after multiple positionings, curves intersected at 200Hz as that seems better to visualize my subjective experience of tonal differences.:

edit: more description here, will add link to final impressions when completed.

 

[theangelboy]

Monoprice AMT sounds like a clear tier above HE6se (modded) in every way aside from tonal balance. Tone is a highly subjective attribute in perception and preference anyway... AMT treble is laid-back tonally, however its speed and clear resolve of fine and low-level detail makes up for the tonal disparity and keeps you totally engaged. This reminds me why I wanted to get rid of vintage Stax Lambda in college, too distracting for studies.

And for the negative: does exhibit a little bit of bass bloom (air pressurization by my definition), a little less than that of Yamaha YH-1. This annoyance is partly mitigated by the unfortunate physical weight of the headphone, meaning I dont expect very long listening sessions more than an hour for Mono AMT. I just did an hour+ and decided it was time for a break for my ears and neck, however it was totally enthralling to hear new detail in music that Im very familiar with especially since the new details emerged from the full-range of bass-mids-highs. The weight strain can be compared to Audeze LCD-X, however LCD-X bass could never hit like this. For reference, HE6se has more bass impact than LCDX 2022, while LCDX 2022 is more resolving of microdetail than HE6se. AMT bests them both from my recollection (will work on final impressions and direct comparisons later).

I think the bass alone is worth price of admission. If weight and bass bloom were not a factor, then I would see AMT as a headphone to aspire to at MSRP. Despite those serious (to me) flaws, a keeper at $300.

An oddity is when attempting to measure on EARS. Not sure what to make of it but there is wide bass variance. Such variance is indicative of pad leak. Yes, the pads are huge and extend past the edges of the mic baffle but the pads are relatively supple so its hard to imagine a leak. idunno

All measures done on EARS, averaged after multiple positionings, curves intersected at 200Hz as that seems better to visualize my subjective experience of tonal differences.:

Interesting impressions. While the AMT tech is very intriguing to me, I can't help but wonder if that recessed area around 3khz would render them unlistenable to me. That area was my main sticking point with the AQ Nighthawk (thankfully, I fixed that with a pad swap). However, headphones that are relatively even in this area (no a sharp dip/spikes) even if they are lower relative to the rest of the frequency response, I'm fine with, like my M565.

I know it's a bit of a moot point since it's modded, but what generation is your T20RP you are comparing here? MKII or MKIII? I find my MKII-based T-X0 almost as oppressively dark as the Nighthawk and it has a similar crater around 3khz (I still need to get around to modding that one).

In your opinion, do you think it's the pads on the AMT causing that dip around the ear gain region or is it an interaction of the driver/housing itself?

 

[Philimon]

I can't help but wonder if that recessed area around 3khz would render them unlistenable to me.

It is polarizing. Some are more sensitive than others to this particular area. I am particularly sensitive to upper mids (approx. 3kHz) and air pressurization. Sensitivity to 3kHz region may also be partly effected by personal listening volumes (see Equal Loudness contour). For reference I find HD650 a tad too forward in the 3kHz department, I keep only as a reference.

but what generation is your T20RP you are comparing here

Tx0RP mods can result in very different sounds... I am using a mk3 which I prefer over mk2 because mk3 has large front-side vents integrated into the pad mounts. The extra venting helps with air pressurization (fatigue) and helps with a quicker and more natural bass decay imo.

In your opinion, do you think it's the pads on the AMT causing that dip around the ear gain region or is it an interaction of the driver/housing itself?

I've no idea, sorry. If I find anything useful later then I will make sure to comment.

I could diy perforations to stock pads to help with air pressure but I wonder what other effects it might have... Hopefully replacement pads arent too expensive. Custom ordered pads from Vesper could help but not cheaply. Im not too concerned atm with fixing ATM's faults.
edit: I see the GL1200 uses velours, looks like a fit.

 

[bagwell359]

As for the upper mid dip it’s big. And the distance of the “baffle” like so many headphones causes a depression in that area, but it’s more than most. If it takes parametric eq well it could solve that

I assume the bass is probably not very potent in terms of impact and EQ probably won’t save it. My mod for that would be still any “baffle” reverb and EQ it with a low shelf. If it can’t at least meet HD-600 impact/timbre levels I can’t use it for 75% of what I listen too

 

[Philimon]

I assume the bass is probably not very potent in terms of impact

Possibly could be hearing a combination of the effect of pressurization (and resulting bass bloom) and incorrectly perceiving as sum of bass impact imparted only by driver. I got that sense from HE6se as well when using solid pads or inner-perforations-only pads similar to Mono AMT's. With similar pads, HE6se seemingly does not have the same kick. Currently I am using HFM "velpads" pads with HE6se as it to me is the best overall without pressurization but it is a trade off as you know. Will take a closer look with full review later.

As for the upper mid dip it’s big. And the distance of the “baffle” like so many headphones causes a depression in that area, but it’s more than most. If it takes parametric eq well it could solve that

The upper mid dip is polarizing. I don't have PEQ unfortunately. I could try Lokius but its a relatively blunt instrument so probably not good for this.

 

[bagwell359]

Possibly could be hearing a combination of the effect of pressurization (and resulting bass bloom) and incorrectly perceiving as sum of bass impact imparted only by driver. I got that sense from HE6se as well when using solid pads or inner-perforations-only pads similar to Mono AMT's. With similar pads, HE6se seemingly does not have the same kick. Currently I am using HFM "velpads" pads with HE6se as it to me is the best overall without pressurization but it is a trade off as you know. Will take a closer look with full review later.


The upper mid dip is polarizing. I don't have PEQ unfortunately. I could try Lokius but its a relatively blunt instrument so probably not good for this.

Yeah you’d need a 31 band or more fixed freq EQ to have a shot at that.

One reviewer called it a “halo” product which I think all AMT drivers are now. 3-5 yrs from now could be a heck of technology maybe the new HEDD will be it.

Planars made huge strides from ‘08 to Susvara in what? ‘16. Ribbons based on what I have heard are ahead of AMT, but it will take competition and big $$ to follow that cited planar burst in an 8 yr period for either tech.

 

[dmagnan]

Yeah you’d need a 31 band or more fixed freq EQ to have a shot at that.

One reviewer called it a “halo” product which I think all AMT drivers are now. 3-5 yrs from now could be a heck of technology maybe the new HEDD will be it.

Planars made huge strides from ‘08 to Susvara in what? ‘16. Ribbons based on what I have heard are ahead of AMT, but it will take competition and big $$ to follow that cited planar burst in an 8 yr period for either tech.

I auditioned the supposedly SOTA RAAL Requisite SR1b ribbon headphones on my system (with the RAAL impedance transformer), and made the comparison. I was disappointed. Overall, it was only slightly better than than the Monoprice AMT - slightly better transparency and resolution, no upper midrange suckout, but less bass and bass quality, and to top it all off, physically uncomfortable and quite inefficient so that my 3-watts into 30 ohms Sparkos Labs Aries headphone amp was only able to drive it to moderate levels. I evaluated sound quality in transparency and resolution and timbral accuracy at moderate levels well below clipping. The RAAL SR1b seems to require 6-10 watts for full volume capability, or use of a speaker amplifier. I sent it back because the small increment of sonic quality wasn't worth the $3500 price for the 'phones plus the cost of a new high power amp, plus the discomfort.

 

[bagwell359]

I auditioned the supposedly SOTA RAAL Requisite SR1b ribbon headphones on my system (with the RAAL impedance transformer), and made the comparison. I was disappointed. Overall, it was only slightly better than than the Monoprice AMT - slightly better transparency and resolution, no upper midrange suckout, but less bass and bass quality, and to top it all off, physically uncomfortable and quite inefficient so that my 3-watts into 30 ohms Sparkos Labs Aries headphone amp was only able to drive it to moderate levels. It seems to require 6-10 watts for full volume capability, or use of a speaker amplifier. I sent it back because the small increment of sonic quality wasn't worth the $3500 price for the 'phones plus the cost of a new high power amp, plus the discomfort.

That amp is not enough to drive the SR1b. My Rag 1 is barely enough and it’s got about 8.5 more db output at 32 ohms. It's like driving the HE-6 with a half watt - one cannot judge the result as the last word; In the speaker world be like driving a big panel speaker with a 35 wpc receiver


If you want bass the Rall CA-1a is a much better choice than the SR1b, and cheaper too.

Tastes differ but the CA-1a with the filter (or without) blows away the HEDD, and a whole slew of $1.5-6k headphones IMO.

 

[trellus]

That amp is not enough to drive the SR1b. My Rag 1 is barely enough and it’s got about 8.5 more db output at 32 ohms.

If you want bass the Rall CA-1a is a much better choice than the SR1b, and cheaper too.

Tastes differ but the CA-1a with the filter (or without) blows away the HEDD, and a whole slew of $1.5-6k headphones IMO.

Well, it should blow away the HEDD at that price when you include the cost of proper amplification, yes?

 

[bagwell359]

Well, it should blow away the HEDD at that price when you include the cost of proper amplification, yes?

I’d say quite a few people spending over $1500 (HEDD debuted at $1899) on a headphone of interesting technology probably have the power. A used Rag 1 is about $675. CA-1a w adaptor isn't that far off at $2500

 

[dmagnan]

That amp is not enough to drive the SR1b. My Rag 1 is barely enough and it’s got about 8.5 more db output at 32 ohms. It's like driving the HE-6 with a half watt - one cannot judge the result as the last word; In the speaker world be like driving a big panel speaker with a 35 wpc receiver


If you want bass the Rall CA-1a is a much better choice than the SR1b, and cheaper too.

Tastes differ but the CA-1a with the filter (or without) blows away the HEDD, and a whole slew of $1.5-6k headphones IMO.

So even though I evaluated the SR1b for qualities of resolution and transparency and imaging at lower power levels well within the capabilities of my Aries amp it still wasn't a valid test? I knew that I could have no valid judgement of bass reproduction abilities and dynamics - that that required a more powerful amp.

 

[dpump]

Please ignore bagwell359. He loves to go on all the HiFiMan threads to try to impose his opinions as the absolute truth. Now he's here to educate all those on this thread. I put him on my ignored list long ago