A Survey of Foster 443742 Variants: Measurements

I'm going to spend the week parsing the differences between a number of the variants of the Foster 443742 (seen on page H-4 of this .pdf). This survey will include: Fostex TH900, TH900mk2, and TH610; Massdrop THX00; Denon ADH-D5000; and the E-Mu Teak stock, and with optionally available Rosewood and Mahogany cups.

Today, I'm just posting up the measurements .pdf. I'll be doing some disassembly and posting basic pictures of the insides on Wednesday. And Friday I'll post my listening impressions.

The measurements are interesting. It's pretty obvious the E-Mu and Massdrop cans are cut from very much the same cloth as the original Denon models. The Fostex TH900, TH900mk2, and TH610 are clearly different.

Looking forward to the listening! Guesses at which I'll prefer welcome in the comments...if you dare.

spyder1's picture


Since you have Fosters attention, can you tell them they need to work on the availability of replacement ear pads. I own Fostex TH900, and replacement ear pads are impossible to find. Replacement ear pads for the Foster 443742 Variant Line are non existent. Foster needs to work on replacement parts availability in the USA.

Eggrenade's picture

There's an interesting difference between the right and left channels for the Massdrop 300 Hz square wave measurement. The frequency response plots don't look too different, so I don't really understand what could be causing the difference.

I'd love to hear your thoughts on the measurement (and sound!), Tyll.

Argyris's picture

Was going to post the same thing. The left channel is clearly ringing much more than the right, and much more than either channel of any of the other headphones sampled. I would say it's either defective or that the damping is different in that channel in this particular sample. Either way, it's probably (hopefully!) not representative of how that headphone should perform.

BaggedMilk's picture

Myself and a few of my friends think that Massdrop is the one making the TH-X00's in some Chinese factories, and that Fostex just either supplies the drivers, or just the design. Just a musing based on how abhorrent the quality control of the X00 is.

BaggedMilk's picture

Look at the frequency response for the left channel. Notice the roughness, especially from 3k on up. The left driver might be defective.

Also, the distortion and bass extension are less impressive than the EMU and the other X00, indicating it probably has worse drivers. ALSO, take a look at the impedance chart. The primary driver resonance on the Massdrop X00 is higher than the Fostex X00.

tidak_ceta's picture


TH900mk1 is better than TH900mk2, especially from THD measurement. am I right?

spyder1's picture

tidac_ceta, thanks for the link!

Btdk34's picture

Looking forward to hearing your impressions on these cans, Tyll! Any word on when the Ether C Flow review will be available? You seemed to like the Ether C very much, I'm wondering what improvements the C Flow will bring to the table. :)

Jazz Casual's picture

I figure that the TH900/mk2 won't be your preferred models. ;)

luvmusik's picture

Tyll rocks for doing this !

Intrigued with #448498 Biodyna/Zelkova wood for sometime now, wish could get my hands on a set; Foster oem appeared at a recent meet couple months ago.

Only models in the related series not included in the run-off so far are EMU Ebony, Massdrop/Fostex TH-X00 Ebony & Purpleheart, Fostex TH600, and Denon ADH-D7000, but he did these last 2 models previously, or posted measurements.

If I had any of the above 6 models, I would send them to him to add for his evaluation. Have EMU-Rosewood and Massdrop/Fostex TH-X00 Mahogany only, preferring the EMU greatly.

Eager for this weekend to read Ty's listening impressions of the bunch included so far !

luvmusik's picture

and...forgot to write on the list the brand new woody Denon AH-7200 too, related to this series. Believe they are Walnut cups, fairly sure they are also biocellulose drivers.

So, total 7 additional related woody headphone types !

luvmusik's picture

...also Denon ADH-D7000 too, since measurements are up & was reviewed before !

Totals 8 additional types in the related series, but not yet included in comparative evaluation so far !

luvmusik's picture

7000 model mentioned twice, oops, sorry ! Gets busy with so many variants...no pressure though, no worries ! There are 7 family-related models not yet included in evaluation, but folks are willing to send these additional models in for inclusion for evaluation!

Wishing someone would release the Zelkova wood Biodyna model Foster oem for $400. !

Joel's picture

I'm surprised how bad the bass distortion are for most of them considering the hype behind the performance of their bass.

gibtg's picture

I have a purpleheart that I'd be game to send in if wanted!

veggieboy2001's picture

Tyll said he'd be interested in measuring almost any can you have...just follow the instructions here:


tomatoshoe's picture

Just made an account to say: Thank you! Looking forward to your impressions... The TH900 have always been one of my favorite headphones and looking to see how the others compare.

Revanna's picture

Just opened up my 610s and there's actual changes to the back of the driver, which seems like good news.

Gonna be interesting to see if they made any equivalent changes for the 900mk2s, then.

germay0653's picture

Interesting to see a difference in the FR measurements between the two because the only difference that I'm aware of is the fixed vs detachable cable of which the metallurgy is supposedly the same.

atkhan's picture

Tyll, some of these woods are waterproof. I mean, well, Teak and Mahogany should at least be, so why do we have to worry about them shrinking and stuff?

eugenius's picture

I'm gonna say you liked the th610 and the e-mu teak mahogany.

I'd like to see the e-mu ebony and especially the th-x00 ebony get measured and receive your subjective impressions. Especially since the x00 ebony is tuned differently than the rest) of the x00's