Is an envelope filter the same thing as an autowah?

Yes Sir .  In the vernacular of some circles of folks.

Re-release of the original Mu-Tron III. I haven't heard one, but it looks like the real deal. Love my original Mu-Tron lll.
 
Cheers,
Tom

I have also heard envelope follower. I think envelope filter is the most descriptive term, since it refers to the envelope reacting to the input volume and adjusting the filter accordingly.

Thanks guys.
 
Yeah, Tom...I've heard good things about the new ones.

Hmm.  Guess I stand corrected - here, I thought Autowah was just some city in Canada....

There is a difference.  With an envelope filter, the effect is in response to the amplitude of the incoming signal.  With an auto wah, the effect is more-or-less determined by a rate setting (this would be analogous to how fast you rocked an actual wah pedal with your foot) and possibly a depth setting - which also does not vary based on amplitude.
 
This is why an envelope filter is generally a more expressive sounding effect - it reacts to your playing.

Hello cje, I hope that you are well ___  
 
Please post a link to a product that exactly conforms to your described parameters _____________.
 
http://en.wikipedia.org/wiki/Auto-wah
 
http://www.pedalspluseffectswarehouse.com/Auto_Wah_Envelope_Filter_Pedals_s/201.htm
 
 
http://www.rukind.com/forum/viewtopic.php?f=319&t=5028

Hey Wolf,
 
Without getting nuts with links, if you just look at the controls of a classic envelope filter (MuTron III) and those of a classic auto-wah (Boss AW-2), one of the key differences is the auto-wah has a rate control - similar to the rate control of something like a tremolo, phaser, etc...  If you let a chord ring out on an envelope filter, you will get a single 'quack' (alteration of the ADSR envelope).  If you let that same chord ring out on a true auto-wah, you will hear the effect cycle over and over at a specific rate, as if you are rocking a wah pedal back and forth - and the effect is not following the envelope of the input signal.
 
Now while it may be true that the amount of 'wah' effect is determined by the amplitude of the signal coming into an auto-wah (but this might not be the case for EVERY auto-wah), I believe the defining elements that make an envelope filter a bonafide auto-wah are the presence of a rate control and the fact that the effect cycles through the filter sweep independent of input signal.
 
If you go to YouTube and watch...
 
OK, OK... I will post one link!!
 

 
This is a Boss auto-wah, and throughout the clip you will see it do things that something like the mighty MuTron III just cannot accomplish - that is, mimic a wah pedal.
 
...and this leads us back to TERMINOLOGY... We would be more correct in referring to these two effect types as auto-wah and envelope FOLLOWER (since they both are very clearly filters).
 
Everything we are talking about here is an envelope filter.  MuTrons and the like are envelope followers, and Boss AW-2s are auto-wah effects.
 
GENUS - filtrum envelopus
SPECIES - followaeus envelopus OR wah automaticus!!

I don't think of auto wah as that technical a term - it could refer to either type of effect (envelope follower or sine wave). Maybe that's the point - different manufactures may use different terms, there is no industry standard for a lot of these terms.  
 
Given that, I have used the effect with Moog stuff - the sine-wave from the CP-251 controlling the filter of the MF-101 low-pass filter (which normally functions as an envelope filter but is actually extremely flexible) - I call it the purr bass:
 
https://soundcloud.com/hieronymous-seven/king-cat-jam

Yes . Ok,  AND that is WHY in my first response in my post #3416, I wrote;
                  in the vernacular of some circles of folks  
Because within the terminology  Auto -Wah  exists a possible debate and issue of semantics  because it is NOT technical terminology.  Thank you very much   .  I have had this discussion somewhere  else before .  It almost make me have a DEJA- VU!

Maybe to answer the original poster's question in its simplest form:
 
An auto-wah is one type of envelope filter.
 
I too have had this discussion a few times!  I bet a lot of us have!