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can no find the specification of cellphone speaker. Is there some indirect method (without disassembling phone) to measure the low frequency response of cellphone speaker? I need to know the lowest frequency that a speaker will reproduce.
Telephones produce 300Hz to 3kHz. The telephone network is spec'd to produce 3kHz at -7.5dB or higher one-way or -15dB or higher in a round trip.
A cell phone with a speakerphone feature might cut frequencies below 600Hz.
yes, I know that most phone speakers have a cutoff frequency around 300Hz. Just want to find low frequency more precisely, in order to set the correct value for Audacity "High Pass Filter" which passes frequencies above its cutoff frequency and attenuates below its cutoff frequency.
Depends audioguru, if he's using the speaker OFF of the cell phone in his own device he's not limited by the signal coming from the phone. To determine frequency responce a simple condensor mic attach to a PC can be used. I use software called DL4YHF's Spectrum Lab to do frequency analays. Condensor mics have very flat frequency responce, flat enough for basic audio calibration at least. So just play back a slowly rising tone from 0hz to 20khz and watch the amplitudes in Spectrum lab.
Also my phone has the ability to play back mp3's and .wav files with a FULL range of frequencies. I've played back sweeps on it before and it has many resonant notches and poor low frequency responce, however it will produce some low frequency sound, just very week so you can't need a lot of power. For their size the quality that comes out of those tiny things is pretty impressive.
The enclosure for a speaker must be designed for the detailed spec's of the speaker for a good flat low frequency response.
You can hear down to 20Hz and feel down to 5Hz but I don't think a little shrieker (not a speaker) from a cell phone can do it.
A speaker's frequency response must be measured in an anechoic space like outdoors. I do it with the speaker's enclosure laying on grass pointing straight up at the mic that is hanging over it.
I'm sure you could generate frequencies down that low, any speaker will, weather or not it's a high enough power level to iritate a fly sitting on the speaker is another thing =) I've DC coupled to a speaker before and run it at 1hz, it's amusing if not completely useless.
What the poster wants to do with the speaker at this point is a big question, in a properly resonant cabinet even a bad speaker can generate decent power at a specific frequency, but it depends on the range he needs as well.
My 1994 486 pc has little speakers built into the monitor that are 1" x 2" and are in bass-reflex little enclosures that have tuned ports.
It is flat down to about 100Hz but not very loud.
I am talking about phone built-in speaker, it's stereo speaker (the phone is low-end, but the speaker itself not bad). I find it's difficult to get the mp3 realtones with good quality of sound (sometimes), this depends from mp3 audio sample, however. If I knew the specific speaker parameters, it would help me to adjust Audacity settings for better result.
Is there some cheap сondenser microphones for PC with standard 3.5mm jack?
Yes. Almost all PC microphones are condenser mics. Just the simple little desktop boom mics, or even the ones for pretty much any headset with a mic on it you'll buy for a PC is a condenser mic.
The problem with quality out of the speaker of the phone you're getting now is like audio said, likely the enclosure itself, and there's really not much you can do about it. The poor quality of sound you're getting out of it may be the ringtones you're downloading themselves not the speaker.
Agreed, depends on mp3 audio source. Ringtones containing mainly single, high frequency tones sounds well, but when the audio clip has a lot of low frequency tones and has a lot of dynamic range (louds and softs), then there is problems.
You can't do anything about that, it's a physical inability of the speaker and it's enclosure to produce the frequencies in question, you could reduce the volume of the peak frequencies to match the maximum of the minimal frequencies and it'll sound really good, it'll also only be able to be heard with the speaker up against your ear in a dead silent room. You'll never get high fidelity audio out of such a speaker without an enclosure large enough to justify using a larger speaker in the first place.
Basically your problem has no sollution in your devices application.
A condenser mic needs a 48V supply to bias its diaphragm and is fairly expensive.
An electret mic uses the electret material to store the 48V charge and is common and very inexpensive.
Some people call an electret mic an electret condenser mic.
What is the mic for? To make acoustical feedback howling?
The tiny speakers that are in cell phones make a very tinny sound because they cannot produce low audio frequencies.
yes, mic for the measuring acoustic feedback. In particular, I want to find what is the low frequency response. How close to place the mic to the phone?
As others have said, for low frequencies you need large speakers and large cabinets - it's all about moving air - and small speakers can't move much air.
You could boost the bass in Audacity, but the bass response will be so poor that it won't help a great deal - you're likely to just distort the sound.
What is the signal source? An MP3 of sine-wave frequencies?
Hold the mic very close to the speaker so room acoustics are at a low level.
Don't allow distortion which contains higher frequencies.
What is the signal source? An MP3 of sine-wave frequencies?
Hold the mic very close to the speaker so room acoustics are at a low level.
Don't allow distortion which contains higher frequencies.
I would have thought the design of the phone tended to do that anyway - you could use Audacity to reduce the bass levels even further, but really you're down to trial and error. Start with an original file that causes you problems, then make different versions with less and less bass, until you find the one that you prefer.
Why do you want to produce tinny squeaky sounds from a tiny speaker?
Make a little speaker with a half-decent 4" driver in a bass-reflex enclosure with a tuned port and driven from a little amplifier IC.
It will produce all frequencies down to about 80Hz and music and voices will sound pretty good..
Yeah, you'd be surprised how good even less than 5 watts can sound in the right enclosure.
shine, you may just be working with crap audio... Have you played this back on a decent sound system to find out if it's the clip itself? re-recording the MP3 may help, it could just be a really low bitrate one, no matter what you do it's gonna sound like crud. Most modern cell phones can play back 192khz mp3 files, some better.
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