[Asterisk-Users] English vs American voice files

[Steve Underwood]

Hi Bill,

Its a while since I used this. I had to look it up. The "rate" effect in 
sox is the default one. It uses a really nasty straight line 
interpolator. The good one is "resample". Try the manual entry for sox, 
and it will tell you the details of how to use it.

Regards,
Steve


Bill Seddon wrote:

>Steve
>
>Can you offer some recommendations regarding the sox arguments to use?  My
>use of sox for down sampling is limited to this kind of command:
>
>sox in.wav -r 8000 out.gsm
>
>Are there other arguments that will give better sound from compressed
>formats?
>
>Thanks
>
>Bill Seddon
>
>-----Original Message-----
>From: asterisk-users-bounces at lists.digium.com
>[mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Steve
>Underwood
>Sent: September 20, 2004 2:33 PM
>To: Asterisk Users Mailing List - Non-Commercial Discussion
>Subject: Re: [Asterisk-Users] English vs American voice files
>
>matt.riddell at sineapps.com wrote:
>
>  
>
>>On 20 Sep 2004 at 12:38, Andreas Sikkema wrote:
>>
>> 
>>
>>    
>>
>>>asterisk-users-bounces at lists.digium.com wrote:
>>>
>>>   
>>>
>>>      
>>>
>>>>Initially we recorded using 16 bit/8K sampling on the basis 
>>>>that this is what is required by Asterisk but that was 
>>>>really terrible.  So we're sampling at higher rates on
>>>>the basis that we can use sox to change it as necessary.  Any
>>>>thoughts on what we can do to make the recordings sound "sharper"?
>>>>     
>>>>
>>>>        
>>>>
>>>We've found that downbsampling with sox resulted in 
>>>significantly lower quality files as those downsampled 
>>>with Cool Edit.
>>>   
>>>
>>>      
>>>
>>Dithering in Cool Edit maybe?
>>
>>Matt Riddell
>> 
>>
>>    
>>
>sox offers several ways to change sampling rates. The poorest one is 
>really quite poor. The best should not be distinguishable from any other 
>good converter over a telecphone line. Dithering is completely 
>irrelevant for telephony. It too  LoFi to notice. :-)
>
>Regards,
>Steve
>  
>