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new to this - Changing sample rate to mix tracks on CD's

Started by AL September 21, 2004
Hi,

I'm a university student studying Electronics Engineering and Bournemouth
University in England.

For my final year project I need to understand how CD mixers work. I know
they alter the sample rate to change the speed (pitch) of the track being
output thus allowing the DJ to mix the tracks (getting the tempo's to
match).

How is this done? Are there specific DSP processors to alter the sample
rate? Or can any standard audio DSP processor be programmed to perform this
task?

Any help/advice/website links greatly appreciated!


AL wrote:

> Hi, > > I'm a university student studying Electronics Engineering and Bournemouth > University in England. > > For my final year project I need to understand how CD mixers work. I know > they alter the sample rate to change the speed (pitch) of the track being > output thus allowing the DJ to mix the tracks (getting the tempo's to > match). > > How is this done? Are there specific DSP processors to alter the sample > rate? Or can any standard audio DSP processor be programmed to perform this > task? > > Any help/advice/website links greatly appreciated!
AL, I got up on the wrong side of the bed this morning. (Actually, I just finished helping someone with a Master's degree turn the paper he's trying to write into comprehensible English. That's worse.) What it boils down to is losing the restraint that would normally deter me from this question: how does someone who has reached the senior year in a university come to write "tempo's" when he means "tempos". There's a very clever (but a bit over wordy) book by Lynne Truss (she's English too) called "Eats, Shoots, and Leaves" that you would do well to read. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
AL wrote:

 > Hi,
 >
 > I'm a university student studying Electronics Engineering and Bournemouth
 > University in England.
 >
 > For my final year project I need to understand how CD mixers work. I know
 > they alter the sample rate to change the speed (pitch) of the track being
 > output thus allowing the DJ to mix the tracks (getting the tempo's to
 > match).
 >
 > How is this done? Are there specific DSP processors to alter the sample
 > rate? Or can any standard audio DSP processor be programmed to 
perform this
 > task?
 >
 > Any help/advice/website links greatly appreciated!


AL,

I got up on the wrong side of the bed this morning. (Actually, I just
finished helping someone with a Master's degree turn the paper he's
trying to write into comprehensible English. That's worse.) The result
is losing the restraint that would normally deter me from this question:
how does someone who has reached the senior year in a university come to
write "tempo's" when he means "tempos"?

There's a very clever (but a bit over wordy) book by Lynne Truss (she's
English too) called "Eats, Shoots, and Leaves" that you would do well to
read. There's a panda story in it.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������

AL wrote:
> Hi, > > I'm a university student studying Electronics Engineering and Bournemouth > University in England. > > For my final year project I need to understand how CD mixers work. I know > they alter the sample rate to change the speed (pitch) of the track being > output thus allowing the DJ to mix the tracks (getting the tempo's to > match). > > How is this done? Are there specific DSP processors to alter the sample > rate? Or can any standard audio DSP processor be programmed to perform this > task? > > Any help/advice/website links greatly appreciated! > >
It's not just changing the sample rate -- you need to alter the tempo without throwing the music out of tune. That's going to be much more sophisticated (and if you find a web site let me know). This is just the sort of thing that a standard DSP processor is made for, given the right software. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com

Jerry Avins wrote:

(snip)

> There's a very clever (but a bit over wordy) book by Lynne Truss (she's > English too) called "Eats, Shoots, and Leaves" that you would do well to > read. There's a panda story in it.
Any relation to the second amendment, "right to arm bears"? -- glen
Jerry Avins <jya@ieee.org> writes:

> AL wrote: > > > Hi, > > > > I'm a university student studying Electronics Engineering and Bournemouth > > University in England. > > > > For my final year project I need to understand how CD mixers work. I know > > they alter the sample rate to change the speed (pitch) of the track being > > output thus allowing the DJ to mix the tracks (getting the tempo's to > > match). > > > > How is this done? Are there specific DSP processors to alter the sample > > rate? Or can any standard audio DSP processor be programmed to > > perform this > > > task? > > > > Any help/advice/website links greatly appreciated! > > > AL, > > I got up on the wrong side of the bed this morning. (Actually, I just > finished helping someone with a Master's degree turn the paper he's > trying to write into comprehensible English. That's worse.) The result > is losing the restraint that would normally deter me from this question: > how does someone who has reached the senior year in a university come to > write "tempo's" when he means "tempos"? > > There's a very clever (but a bit over wordy) book by Lynne Truss (she's > English too) called "Eats, Shoots, and Leaves" that you would do well to > read. There's a panda story in it.
And when's the last time you saw someone struggling with "who/whom"? We just don't even try any more. -- Randy Yates Sony Ericsson Mobile Communications Research Triangle Park, NC, USA randy.yates@sonyericsson.com, 919-472-1124
Randy Yates wrote:

> Jerry Avins <jya@ieee.org> writes: > > >>AL wrote: >> >> > Hi, >> > >> > I'm a university student studying Electronics Engineering and Bournemouth >> > University in England. >> > >> > For my final year project I need to understand how CD mixers work. I know >> > they alter the sample rate to change the speed (pitch) of the track being >> > output thus allowing the DJ to mix the tracks (getting the tempo's to >> > match). >> > >> > How is this done? Are there specific DSP processors to alter the sample >> > rate? Or can any standard audio DSP processor be programmed to >> > perform this >> >> > task? >> > >> > Any help/advice/website links greatly appreciated! >> >> >>AL, >> >>I got up on the wrong side of the bed this morning. (Actually, I just >>finished helping someone with a Master's degree turn the paper he's >>trying to write into comprehensible English. That's worse.) The result >>is losing the restraint that would normally deter me from this question: >>how does someone who has reached the senior year in a university come to >>write "tempo's" when he means "tempos"? >> >>There's a very clever (but a bit over wordy) book by Lynne Truss (she's >>English too) called "Eats, Shoots, and Leaves" that you would do well to >>read. There's a panda story in it. > > > And when's the last time you saw someone struggling with "who/whom"? We > just don't even try any more.
Whom says? ;^) Jerry -- Engineering is the art of making what you want from things you can get. &#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;
Thank you Tim for some insight into the questions I asked.



I though that this being a "public" newsgroup I would be able to post a
seemingly innocent question without being blown away by some
incomprehensible babble on my inconsequential misplacement of a comma.



I admit my post was made in some haste; I am excited about a new project I
hope to start soon therefore did not have the foresight to gather the Oxford
English dictionary and Roget's thesaurus and ready myself properly for the
almighty task of putting together a request on an internet newsgroup.



So am I to gather from Mr Jerry Avins' comments that I am in fact not
welcome here? Is this some sort of clique that only seasoned professional
electronic engineers with an exquisite command of the English language can
attend and pass comment and judgment upon the naive wanderer who may
actually just only require some gentle advice? A prod or push in the right
direction so to speak?



If my question was not an acceptable one please someone point out why? I was
under the impression if you were polite enough and I have no reason to
suspect my post was not, some advice could be asked of the high and mighty
knowledgeable of the internet brethren.



Anyway it's now approaching 3AM in London, so I must close this case. I
apologise for any inconvenience caused as only a misplaced comma can.



AL.



"Tim Wescott" <tim@wescottnospamdesign.com> wrote in message
news:10l1bseqqs6s8b0@corp.supernews.com...
> AL wrote: > > Hi, > > > > I'm a university student studying Electronics Engineering and
Bournemouth
> > University in England. > > > > For my final year project I need to understand how CD mixers work. I
know
> > they alter the sample rate to change the speed (pitch) of the track
being
> > output thus allowing the DJ to mix the tracks (getting the tempo's to > > match). > > > > How is this done? Are there specific DSP processors to alter the sample > > rate? Or can any standard audio DSP processor be programmed to perform
this
> > task? > > > > Any help/advice/website links greatly appreciated! > > > > > It's not just changing the sample rate -- you need to alter the tempo > without throwing the music out of tune. That's going to be much more > sophisticated (and if you find a web site let me know). > > This is just the sort of thing that a standard DSP processor is made > for, given the right software. > > -- > > Tim Wescott > Wescott Design Services > http://www.wescottdesign.com
If you are thinking of a hardware solution like building a board for
your project, i am pretty sure there are codecs (alternatively ADC and
DAC chips) that support sample rate conversion. Check out codecs from
cirrus logic. You do not need a DSP in this case because,
simplistically speaking, you are not doing any kind of processing on
the data coming from the ADC or codec.

I am new to this list and this is infact my first attempt at answering
queries. So please cross check with somebody more knowledgeable.

Thanks.

-vj



"AL" <me@home.com> wrote in message news:<FtW3d.45331$U04.4095@fe1.news.blueyonder.co.uk>...
> Hi, > > I'm a university student studying Electronics Engineering and Bournemouth > University in England. > > For my final year project I need to understand how CD mixers work. I know > they alter the sample rate to change the speed (pitch) of the track being > output thus allowing the DJ to mix the tracks (getting the tempo's to > match). > > How is this done? Are there specific DSP processors to alter the sample > rate? Or can any standard audio DSP processor be programmed to perform this > task? > > Any help/advice/website links greatly appreciated!
AL wrote:

> Thank you Tim for some insight into the questions I asked. > > > > I though that this being a "public" newsgroup I would be able to post a > seemingly innocent question without being blown away by some > incomprehensible babble on my inconsequential misplacement of a comma.
It was an apostrophe. I'm sorry I flew off the handle. I hope it's uncharacteristic.
> I admit my post was made in some haste; I am excited about a new project I > hope to start soon therefore did not have the foresight to gather the Oxford > English dictionary and Roget's thesaurus and ready myself properly for the > almighty task of putting together a request on an internet newsgroup. > > > > So am I to gather from Mr Jerry Avins' comments that I am in fact not > welcome here? Is this some sort of clique that only seasoned professional > electronic engineers with an exquisite command of the English language can > attend and pass comment and judgment upon the naive wanderer who may > actually just only require some gentle advice? A prod or push in the right > direction so to speak?
Not at all. Welcome is extended to all except perpetual boors. As an occasional boor, I seem to be tolerated.
> If my question was not an acceptable one please someone point out why? I was > under the impression if you were polite enough and I have no reason to > suspect my post was not, some advice could be asked of the high and mighty > knowledgeable of the internet brethren.
Had I known how to answer intelligently, I would have appended my contribution to my tirade. My silence on the matter was the result of ignorance, not pique.
> Anyway it's now approaching 3AM in London, so I must close this case. I > apologise for any inconvenience caused as only a misplaced comma can. > > > > AL.
Good luck with your project. Jerry -- Engineering is the art of making what you want from things you can get. &#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;