More Stax Measurements: SR-009; SR-007; SR-507; SR-404 Ltd; SR-404; and SR-003

I'm making ready to head off to RMAF, but I certainly didn't want to shirk my duties measuring Stax headphones, and getting them back to their rightful owners.

Unfortunately, I just did a quick listen on each and didn't have time for listening tests, so other than a couple of notes here and there, I'll let the measurements speak for themselves.

We'll start with the round ear-piece; the rectangular ear-piece Stax will be on the next page.

Stax SR-009 New Out of Box (# SZ9-1278)
This is a brand new headphone of the second batch of SR-009 (shipped about mid-Sept '11), fresh out of the box. Compared with the first pair of SR-009s, which had some break-in time, the measurements are near identical with the exception of the THD+noise. It will be interesting to see if anything happens after they're used some, though it's just as likely an error in measurement. I'll be re-measuring these after RMAF.

Click on graphs image to download .pdf for closer inspection.

Stax SR-009 (# SZ9-1207)
This is the first SR-009 I used during the high-end comparison. Wow! They sounded great. Look hard, there's some magic in these measurements.

Click on graphs image to download .pdf for closer inspection.

Stax SR-007 (# SZ1-1023)
These are a late model Mk 1.

Click on graphs image to download .pdf for closer inspection.

Stax SR-007 (#SZ3-1576)
These are a Mk 2.5 version.

Click on graphs image to download .pdf for closer inspection.

More measurements of rectangular Stax next page ...


Jazz Casual's picture

Thanks again Tyll. Am I right in thinking that the SR-404 holds its own against the pricier SR-507, and that the SR-404 LE looks like the pick of the Lambda bunch?

Shufny's picture

Do you plan on remeasuring the Qualia 010? I would be really intrested since your previous one seems like it had a bad seal. I assume this is the reason it's not among the data sheets.

Stefraki's picture

Have been looking forward to seeing some Lambda measurements. Pretty much what I expected from the ones of those I've heard. I can see why I like the 507s the most - it's that extra little bump in the deep bass between 20 and 40 hz that counters the Lambda treble emphasis so well.

The Monkey's picture
RMAF Baby!
jeffreyfranz's picture

Great contribution to our understanding of this family of phones. Thanks, Tyll.

I do have one question: Why is the SR-507 the only one with a positive-phase impulse response, while all the others are inverted (even the 009)?


Tyll Hertsens's picture
That remains a mystery at the moment. From what I can gather it's most likely something in the test set-up. Not sure where it's coming from, but next time I get the gear in, I'll peck my way through it.
Exe_Arco's picture

I've never listened to some Stax before, and I really quite want to but they are rather out of my budget.

Anyway, not the topic of my question.

It seems as if all Stax have a drop right after 1k, is there any known reason for this?

Also, would it be possible for you to measure some of the other known Stax, such as some older and more low end Stax.