URGENT!!! need help finding a topic to do a huge paper on by tomorrow!

[knifemyglitter]

i have a 20 page paper in my audio class due at the end of the semester and i have to have a topic by tomorrow. everytime i try and email my prof with a subject, he keeps saying "needs to be more cutting edge" but the problem is, most cutting edge stuff doesnt have a lot of informational sources that i could base a report off of. If anybody has any idea of something cutting edge in audio that has a lot of technical information at my disposal (20 pages or so worth) ... id appriciate it so much. Thanks.

Kevin

 

[Kyanzes]

You could try to find something on audio compression or storage. Couldn't come up with anything else that could be remotely called cutting edge. Then again I'm not in the audio business.

 

[bobsmith1492]

You could look into the history of Class D amplifiers, their potential and current use and whatnot; they're _pretty_ cutting edge (been around awhile, but not very widespread and still have good potential).

 

[bobsmith1492]

You could look into the history of Class D amplifiers, their potential and current use and whatnot; they're _pretty_ cutting edge (been around awhile, but not very widespread and still have good potential).

EDIT: And, you could do it twice for good measure!

 

[PottedMeat]

Originally posted by: bobsmith1492
You could look into the history of Class D amplifiers, their potential and current use and whatnot; they're _pretty_ cutting edge (been around awhile, but not very widespread and still have good potential).

Yeah that could be interesting, depending on how technical you want to get - Here's a summary of Class D operations:

International Rectifier - Class D Audio Amplifier Basics

You'd probably want to do some background on efficiency of A/B/AB amplifiers too but do a little expanding and BAM you've got 20 pages.

 

[Chapbass]

What about the changes that computers have made in the audio recording world? Talk about the changes that Protools, cubase, etc. have brought in with the change over to plug-ins instead of actual rackmount gear.

Also obviously the editing being much easier as well as portability (many artists can now record albums in their tour buses with 24 track recorders such as rolands VS2480 and the akai DPS24...pretty sure thats what its still called...been a while)


Going into the history of audio recording would give you a TON of information, as well as changes in studio design, live sound, etc. You could also do the new cutting edge stuff, such as the new emphasis on 5.1 and 7.1 audio, DVD-A, etc.


If the digital recording era isnt cutting edge...i dont know what is.


The question is...is it close enough related to audio? i think it is but thats up to your prof.

 

[knifemyglitter]

thanks sooo much everyone. I went with Class D amps and he approved it. Please let me know if you know any other good sources that i could use for this. that last one was amazing.

Kevin

 

[spidey07]

Why not look at non conventional speaker designs like electrostatic and other "non woofer/tweeter distortion box" approaches?

 

[emoxley]

There's Dolby Digital Plus and Dolby True HD audio formats, as well as DTS-HD. (Maybe for your next paper)
You can't get much more "cutting edge" than these.......

 

[CSMR]

Room and speaker correction DSP?

 

[CRSTech06]

Speech recognition?

 

[diggerbucket]

Anti-noise.

 

[xtknight]

Head-related transfer function

 

[Vegitto]

You could do it about why people spend thousands upon thousands on audio equipment when they are physically unable to tell the difference.

 

[spidey07]

Originally posted by: Vegitto
You could do it about why people spend thousands upon thousands on audio equipment when they are physically unable to tell the difference.

Never heard a good stereo I assume?

 

[Howard]

Tapped horns
Synergy horns
danleysoundlabs.com

Oblate spheroidal waveguides
gedlee.com

Ripoles (dipoles with air mass loading to lower Fs)

Active Impedance Control
http://www.eighteensound.com/index.aspx?mainMenu=research

hmm...

http://www.diyaudio.com/forums/forumdisplay.php?forumid=49

 

[spidey07]

Howard,

How about some of the innovative "active" or servo sub designs out there? I haven't kept up on it but with the explosion of home theater there seems to be more development in this area.

 

[Howard]

Motional feedback (MFB) is old hat. It just isn't popular due to the extra complexity.

Basically, you measure the motion of the diaphragm and send the results back to the amp to correct, reducing distortion and allowing almost any kind of response modification (change Q, Fsc). You can use a sensing coil adjacent to the voice coil and integrate the signal (it reads velocity) to get acceleration (which is what makes the sound). Or you can use an accelerometer, or even an optical device that reads the displacement of a light or what have you.

You can change the response using a simple low-pass if you run the [sealed] sub below the box's Fsc, where the response drops off at 12dB per octave which is easy to correct. This results in pretty low efficiency and requires huge power to get loud, and accordingly most drivers used in this config will suffer significant power compression. This too is not new tech - it's called Extended Low Frequency (ELF).

The Linkwitz transform is much more elegant in that you can use it with any sealed box to change the Q and Fsc. The efficiency is higher than with an ELF config since you can use a bigger box. It's pretty fun to play around with the model; give it a shot. http://www.trueaudio.com/downloads/linkxfrm.xls

There are also some feed-forward designs where you proactively correct the distortion by modeling the driver's behaviour and changing the signal as required. I don't know much about this kind of configuration, though.

 

[spidey07]

Thanks.
:thumbsup:

So what you're saying is this technology is nothing new?

 

[dkozloski]

The effects of rolling the fuzzy side in on your birch bark moose calling horn.

 

[Howard]

Originally posted by: spidey07
Thanks.
:thumbsup:

So what you're saying is this technology is nothing new?

Yes. Motional feedback combined with current-drive amplification has great potential, though. See:

http://www.essex.ac.uk/ese/research/aud...20reduction%20MC%20current%20drive.pdf

http://www.essex.ac.uk/ese/research/aud...ills-Hawksford%20power%20amplifier.pdf

 

[spidey07]

Thanks Howard. Always a pleasure.
;thumbsup;

 

[sao123]

AM radio is still pretty cutting edge as far as my parents are concerned.

how about sattelite radio distribution... possibly even in tunnels and other unsignalable areas. I remember pittsburgh did something like this to a few of their tunnels.

 

[WildHorse]

Bragg Cells

Bragg cell, uses the acousto-optic effect to diffract and shift the frequency of light using sound waves (usually at radio-frequency)

 

[davesaudio]

poke around diyaudio. clever guys are playing with tripath modules and the like