Background: I've been impressed by the inexpensive Marantz MPH-2 ($39.99)—especially its bassy, non-fatiguing sound. The MPH-2 is one of 5-6 "clones" (re-licenses) of the original ISK MDH9000 design. I've owned 3 pairs of them (kept one MPH-2, gave the other plus a LyxPro HAS-30 as gifts). As long as they use the same quality pleather earpads found on the Marantz & LyxPro, the clones sound identical. Recently I became impressed by the intricate, imaginative mods posted on Head-Fi by @Slater. He also likes the MDH9000 clones—so I asked if he'd do a top-to-bottom mod of a new one.
His mods included:
This review compares his modded Akai Professional 50X headphone to my stock Marantz MPH-2. I listened to the mod for weeks on a range of music (studio pop, blues, R&B, funk, rock, jazz, Afropop, reggae, a bit of classical). To identify mod vs stock differences, I switched these headphones repeatedly (same cable, amp, volume) to compare their sound on the same music cuts.
CONCLUSION:
(didn't think I'd make you wait for it, did you?)
The modded headphones are significantly improved in nearly every way vs stock. It's one of the most fun headphones I've heard (my feet tap whenever I hear it). It's an understatement to say @Slater's mods were successful: these mods showed me just how good this driver & enclosure can sound (details below…)
Frequency range/sonic profile:
The greatest change in the mod vs stock is here, something I least expected. The basic sonic profile of the stock headphone is retained in the mod, but with many changes:
Resolution: Compared to stock, it's as if 2-3 layers of cotton have been removed. The clarity and resolution of the mod are far beyond what the stock headphone can do. IMO this is the most surprising benefit of the mods. I hear "into the music" on the mod in ways I can't on stock.
Dynamics: The stock headphone has a pleasing sound but isn't particularly dynamic, with soft/loud differences not very good unless the volume is cranked. The mod improves on this, with dynamics that range from above average to excellent, depending on the source. Improved dynamics combined with greater resolution make the mod compelling and exciting to listen to.
Soundstage: The stock headphone's better-than-average soundstaging is one of its best qualities. Still, the mod is better, as expected with open-back conversion. The headspace is larger; notes are a bit further from my head all around, and sound placement in space is distinct. The channel separation is also improved (didn't expect that). The net effect is that notes surround my head; on the mod, percussion in particular sounds very distinct & well-anchored in sonic space.
COMMENTS
Clearly I like @Slater's modded Akai. But I also want to understand where it fits in the headphone landscape. Did the mods make the Akai the equal of the Sennheiser HD800 or Focal Utopia? Of course not. Even fully modded, this headphone is middle-of-the-road audio, falling short of the finesse & refinement of TOTL designs. In the more affordable realm, I've heard 3 headphones whose sound is roughly comparable to the mod.
Finally, there is even some user-customization available in the mod (Figure 8). One simply removes the earpads and covers more or fewer of the 18 exposed holes that ring the driver (9 holes on each side). The mod came to me with a total of 8 of the 19 holes covered (4 covered on each side). @Slater explained that I could increase bass (and simultaneously drop midrange level) by uncovering holes; or do the reverse by covering more holes. I played with this enough to know that I couldn't really improve on his tuning.
His mods included:
- Bullet-proofed hinges
- Replaced stock, locking 3.5mm jack w/a universal flush mounted 3.5mm jack
- Converted the earcups from closed to open
- Opened front driver grille holes
- Tuned front cup face ports
- Coated inside of cups with rubber dampening compound
- Stacked N52 magnet on drivers
- Resoldered all connections with silver solder
- Burn-in (150 hours)
- Installed baffling inside of cups
- Installed LyxPro HAS-30 pads
- Tuned stock driver
- Replaced stock, locking 3.5mm jack w/a universal flush mounted 3.5mm jack
- Converted the earcups from closed to open
- Opened front driver grille holes
- Tuned front cup face ports
- Coated inside of cups with rubber dampening compound
- Stacked N52 magnet on drivers
- Resoldered all connections with silver solder
- Burn-in (150 hours)
- Installed baffling inside of cups
- Installed LyxPro HAS-30 pads
- Tuned stock driver
This review compares his modded Akai Professional 50X headphone to my stock Marantz MPH-2. I listened to the mod for weeks on a range of music (studio pop, blues, R&B, funk, rock, jazz, Afropop, reggae, a bit of classical). To identify mod vs stock differences, I switched these headphones repeatedly (same cable, amp, volume) to compare their sound on the same music cuts.
Going in, I assumed the modded headphone would sound very similar to stock (ie, stock tuning would be preserved); and the soundstage would become larger & better courtesy of open-back conversion. Well…I was 1/2 right.
CONCLUSION:
(didn't think I'd make you wait for it, did you?)
The modded headphones are significantly improved in nearly every way vs stock. It's one of the most fun headphones I've heard (my feet tap whenever I hear it). It's an understatement to say @Slater's mods were successful: these mods showed me just how good this driver & enclosure can sound (details below…)
Figure 1: Mod on left, stock on the right. Note the fine workmanship required to cut out & inset the grill
Frequency range/sonic profile:
The greatest change in the mod vs stock is here, something I least expected. The basic sonic profile of the stock headphone is retained in the mod, but with many changes:
BASS – The stock bass is large & in charge, anchoring the entire sound. It's broadly shelved up above neutral, with more sub-bass than usual. The mod's bass is definitely better: still elevated, but less so (an improvement); the sub-bass is strong; and the entire bass is more tuneful & accurate, conveying low tones with greater clarity, definition, and timbre. The mod is a borderline basshead headphone…a good thing.
MIDS – The midrange of the stock Marantz is somewhat recessed, pleasant-sounding but not very clear. The midrange of the mod is a big improvement, conveying much more musical information. I hear subtle musical details on the mod that are barely audible (if at all) on the stock. For example, the mod is a terrific percussion headphone; stock is not.
- the upper mids can sound a bit sharp on the mod, depending on music & source. This is something few besides me would even hear, as I'm quite treble-averse (@Slater did not hear it at all). I quickly got used to this, though I played around a bit with fabric damping.
- See comments below about tuning holes
Figure 2: showing both grills of the mod
Figure 3: showing the stock/recessed/locking input jack
Figure 4: showing the mod's flush-mounted input jack
Figure 5: closeup of the mod's flush-mounted input jack
Figure 6: an aftermarket 3.5mm cable's jack plugged in...a perfect fit
Figure 3: showing the stock/recessed/locking input jack
Figure 4: showing the mod's flush-mounted input jack
Figure 5: closeup of the mod's flush-mounted input jack
Figure 6: an aftermarket 3.5mm cable's jack plugged in...a perfect fit
Resolution: Compared to stock, it's as if 2-3 layers of cotton have been removed. The clarity and resolution of the mod are far beyond what the stock headphone can do. IMO this is the most surprising benefit of the mods. I hear "into the music" on the mod in ways I can't on stock.
Dynamics: The stock headphone has a pleasing sound but isn't particularly dynamic, with soft/loud differences not very good unless the volume is cranked. The mod improves on this, with dynamics that range from above average to excellent, depending on the source. Improved dynamics combined with greater resolution make the mod compelling and exciting to listen to.
Soundstage: The stock headphone's better-than-average soundstaging is one of its best qualities. Still, the mod is better, as expected with open-back conversion. The headspace is larger; notes are a bit further from my head all around, and sound placement in space is distinct. The channel separation is also improved (didn't expect that). The net effect is that notes surround my head; on the mod, percussion in particular sounds very distinct & well-anchored in sonic space.
- One advantage of the open mod is a more relaxed feeling when it's on my head…less of that "pressurized" feeling I get w/stock. As a result, I can listen longer.
- Despite being open-back, the mod is still relatively isolating, perhaps because the grill/opening is <1/2 of the total outside surface of the earcup. However, anyone needing complete silence in a shared workspace may have issues with the mod (not the stock headphone--it's dead quiet).
COMMENTS
Clearly I like @Slater's modded Akai. But I also want to understand where it fits in the headphone landscape. Did the mods make the Akai the equal of the Sennheiser HD800 or Focal Utopia? Of course not. Even fully modded, this headphone is middle-of-the-road audio, falling short of the finesse & refinement of TOTL designs. In the more affordable realm, I've heard 3 headphones whose sound is roughly comparable to the mod.
Fidelio X2 is an open-back dynamic that retails for ~$300. It has much less sub-bass than the mod, along with an elevated mid-bass. The soundstaging is more diffuse than the mod's, but somehow more satisfying. I prefer the X2s primarily because they are a little more relaxed (though still fun).
Onkyo A800 is an open-back dynamic that retails for ~$400. It is somewhat less outgoing than the very fun modded Akai. It has less bass than the mod overall, and definitely less sub-bass. My vote goes to the mod.
Sony MDR Z7 (a closed back design that retails for $699) clearly has more refinement and resolution than the mod, though less sub-bass. Still, it sounds somewhat muted unless cranked (not a problem with the mod). For me, it's a toss-up between it & the mod.
In other words, these mods pushed the sonic value of the Akai to ~5X–15X its retail cost. That's just one person's opinion—but still, it's quite an achievement for the mod to match up with costlier headphones.Onkyo A800 is an open-back dynamic that retails for ~$400. It is somewhat less outgoing than the very fun modded Akai. It has less bass than the mod overall, and definitely less sub-bass. My vote goes to the mod.
Sony MDR Z7 (a closed back design that retails for $699) clearly has more refinement and resolution than the mod, though less sub-bass. Still, it sounds somewhat muted unless cranked (not a problem with the mod). For me, it's a toss-up between it & the mod.
Finally, there is even some user-customization available in the mod (Figure 8). One simply removes the earpads and covers more or fewer of the 18 exposed holes that ring the driver (9 holes on each side). The mod came to me with a total of 8 of the 19 holes covered (4 covered on each side). @Slater explained that I could increase bass (and simultaneously drop midrange level) by uncovering holes; or do the reverse by covering more holes. I played with this enough to know that I couldn't really improve on his tuning.
Figure 7: showing the 18 tuning holes, 9 per side (all uncovered here)
Loaner: I'd be happy to loan this modded headphone to anyone who's curious about its sound. If you'd like to borrow it, pls PM and I'll send. If more than one person wants to hear it, I'll ask the 1st to send it to the 2nd at their expense, and so on. And please PM @Slater for more information, if you're interested in exploring this modded ISK MDH9000 clone.
