Hello all,
 
I have a client who needs telephone on-hold audio spots (spoken work) delivered to them as follows:
 
mono, 8000Hz sample rate, 64 kbs
 
Can someone recommend a (hopefully free) tool that will convert my 16 bit mono files to this format?
 
Thanks.
Dave

We use the DBpoweramp app.  Works for converting most anything to most anything else.  It will even do 12 and 8 bit Ulaw conversions...which many older phone systems still require (even tho they sound like arse).  It's cheap too!

http://www.wavosaur.com/

will probably do it and also has a batch mode

as well as dbpoweramp / DMC , which rolo already mentioned.

Thanks!  I downloaded DBpoweramp, and it seems to do the job.  The 8k mono has a defined knps of 7 rather than 64, but I presume this is no problem.  8k and 7kbps is pretty awful sounding. :-)

Hi Dave. I have had a fair bit of experience producing On hold messages a while back. Despite the phone not being a great reproduction medium the idea of delivering a low Fi signal into the phone system is a silly one. Firstly do they want to store a million phone message hence the need for such small files. I would say not.

It is still better to feed in something that sounds great into the phone system. The resultant sound will still sound better on the phone. I actually supplied wave files at 44.1 16 bit but decent mp3's would also suffice.

What is important though is setting the EQ of the final mix before it goes into the phone. What I found worked very well was to get a phone from somewhere and rip off the handset. I connected a headphone jack to the ear piece and monitored the mix through the phone while I applied the final EQ. You do need to EQ a bit. eg roll off the bass and adjust the mids etc for a nice clear sound in the handset and it can be done.

While Jeff is right that sometimes you can force a higher bit resolution onto a given system, etc...he misses a crucial point in vendor/client relations.  Quite often, the client doesn't know 8 bit Ulaw from 24 bit 48khz.  Or anything in between.  And no amount of cajoling, explaining or "training" will change their minds from the simple booklet that came with their phone system which insists that all files being dumped into it are mono 8bit Ulaw files.  So be it.  Don't argue.  Give them what they ask for.  They won't know or care.  And they will come back to you again and again.  And they will not consider you a pedantic horses behind for continually trying to "educate" them.  At least that's been my experience...for over twenty five years now:-)  YMMV.