Jump to content

12-20khz generator


cmassey

Recommended Posts

Ok, this is sorta in our realm. I want to build a tone generator for those freq. I can no longer hear. As a joke, and without being mean about it, I want to be able to take on set and just check those around me!!! I have a 8w amp already built, figure i drive my FOSTEX speaker and just see who responds!!!

The things the mind comes up when bored...

thanks....cleve

Link to comment
Share on other sites

Now that a pretty cool generator....i was thinking more along the lines of a circuit with a basic 555 chip, a few parts and in the same box with my little amplifier! Keep it clandestine, and then turn on the flashing lights when someone starts to complain about headaches!!!!

Link to comment
Share on other sites

Well, a 555 squarewave is going to leave you with tons of subharmonics in the dialog range. Maybe an RC instead? http://www.electroni...oscillator.html

The other question is... does your portable speaker even have much response above 10 kHz? The ones I've tested have been pretty poor...

The Real-World Case Against Small Speakers

So far we’ve dealt with small speakers in the abstract. But once you get to real-world

examples, the problem isn’t just lost highs and lows—it’s also what the speaker does

to the middle. Good full-size monitor speakers are accurate over their entire range.

Mixes you do on them will sound right on any other good monitor and will at least be

predictable on most tiny monitors. But bad speakers are random; corrections that

improve the sound on one may make it a lot worse on another.

For example, there’s a small powered monitor that’s been popular for years. It

looks professional, even has XLR connectors, and is often bundled with expensive

dedicated nonlinear editors. It doesn’t sound professional. A speaker-designer friend

of mine tested them with lab equipment, and I used what he discovered to retouch our

frequency-analysis plot. The result is Figure 11.4.

Waves’ PAZ will never look like this

on your screen, but my version accurately depicts how these speakers distort the sound

balance.

The high and low ends disappear in the figure because they also do in the speaker.

While the manufacturer claims a low-frequency limit of 80 Hz, things are very quiet

down there. In reality, the bass starts to fall off drastically at 150 Hz and is essentially

too soft to be useful by 100 Hz. The opposite happens to the highs: to reach a claimed

13 kHz cutoff, they apply a gigantic boost at 8 kHz; these speakers practically beg you

to make the mid-highs too soft! To top it all off, there’s a major dip between 1 and

2 kHz—probably to make pop music sound better on them. Nobody could do an accurate

mix with this kind of frequency response. Worse, all that equalization adds signifi

cant distortion.

A different multimedia speaker is often bundled with multi-processor towers,

high-end video cards, and expensive NLE software. It consists of multiple 1-inch diameter

speakers in a narrow stick, designed to sit on either side of your video monitors.

This arrangement is even worse: along with the uneven response caused by equalization,

the frequency response doesn’t even stay the same when you move your head.

That’s because the length of the path from each individual tiny speaker to your ear will

be different depending on head position, causing random cancellations and reinforcements

(Chapter 1).

-- yours truly, Producing Great Sound 3/e page 237
Link to comment
Share on other sites

  • 3 weeks later...

Oh, I think I know what speaker Jay is talking about... used in practically every edit bay known to man (that I've seen).

Back to the generator idea: I use the one in my iPhone, SignalSuite, and hose that out to a speaker if I need to test something:

iPhone_Portrait_SignalSuite2_200w.pngmzl.xvddwysq.320x480-75.jpg

This thing will generate damn near any thing -- sine waves, square waves, pink noise, white noise, sweeps, you name it. $9.99 on the app store.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...