Sound recording to Computer?

Subject: BS: Sound recording to Computer?
From: GUEST,Grateful Guest
Date: 08 Jun 06 - 01:17 AM

I'm scanning family photos to my computer's hard drive. Going to burn them all into disc for the family someday. Lots and lots of photos. I have a Pentium 4, Windows XP, and a hard drive way bigger than I ever thought I'd use. So, the older members of my family look over my shoulder and tell stories about the crumbling old pictures. Good stories. Funny. Informative. Stuff that ought to be preserved, but I don't do stenography.

I figure I can put over a thousand photos on a CD-R, but it occurred to me I should try to record some of these stories too. And preserve the voice print along with the visual print of these folks. But I have no experience with modern recording.

There's some inexpensive software out there that says it can do it all, so I guess I could hook a mic into a USB port or do tape recordings and line them in somehow, but I was wondering about storage space. What format should I use (MPEG, WAV?). This is the stuff I know nothing about. Can't you compress the heck out of sound files? Most of the photos I'm storing are around 300-400 KB. Can I store sound files that would be intelligible at that size?

Any suggestions on software, type of mic and how to line it in (can I use a USB port?), compression methods, type of file and so on would be appreciated.

Found this software that says it can do it all.

http://www.mp3towav.org/i-Sound-WMA-MP3-Recorder-Professional/

Subject: RE: BS: Sound recording to Computer?
From: Amos
Date: 08 Jun 06 - 02:50 AM

For the kind of fidelity you need, your best bet is to use MP3 compression which can reduce a WAV or AIFF soundfile down to a quarter or even a tenth of its original size with so little loss of quality as to not be especially noticeable.

You can by USB mics. There is also a USB device called an iMic which takes standard mic jacks and hooks into a USB port, which can be had for relatively little and is quite convenient.

If the software you are using allows you to save directly to MP3s, that would be the best way IMO.

Otherwise the source file (WAV or AIFF) has to be converted. iTunes will do this.

A

Subject: RE: BS: Sound recording to Computer?
From: Hitchin' John
Date: 08 Jun 06 - 03:52 AM

Hi

To record spoken word is not very demanding so a reasonable quality mike especially a USB should work well.

Concerning format - you should consider what will be your most likely playback medium. CD audio is playable on a wide variety of equipment MP3 is playable on fewer types of equipment but requires smaller files.

It is easily possible to convert WAV files to CD or MP3 but can be a little time consuming to do much editing. Remember it is always worthwhile to do another backup while CD-Rs are so cheap.

It should be possible to produce discs playable on DVD machines with both audio and pictures, but I have not experimented with that myself

Subject: RE: BS: Sound recording to Computer?
From: Amos
Date: 08 Jun 06 - 11:18 AM

IF you have a Mac, it's as easy as making a movie.

A

Subject: RE: BS: Sound recording to Computer?
From: GUEST,Grateful Guest
Date: 08 Jun 06 - 11:36 AM

Thanks for the input. What I'm hoping to do is burn CD-Rs with the pictures AND some sound recording. That way the family viewer in the future can click on the picture or, if he/she has speakers, click on the sound file. I don't think there will be a problem with that if I just burn it all as data, but I can experiment on that.

I think Windows Media Player is pretty standard for playback on PCs now, and Macs can play it all.

I guess I need to know about file size. A compressed WAV file (playable on computer but not CD player?)--is there any way to calculate how many KB per second or minute for a compressed file? I need to decide if this is even practical before pursuing it.

Really am grateful. Already know a lot more than I did. I wasn't even sure if microphones came with USB plugs nowadays.

Any more guidance would be much appreciated.

Subject: RE: BS: Sound recording to Computer?
From: GUEST,petr
Date: 08 Jun 06 - 11:40 AM

speaking of backup
make sure you use discs that are archival quality - such as verbatim
(theres another brand as well - which escapes me, Tayoung ?) apparently theyve been reducing the coating on cds and over time it evaporates.

The US Army is suing some cd manufacturer - they backed up the last 30years of medical records - shredded the paper copies and found out a couple of years later the cds were no good. (the coating evaporated and they were unreadable)
There is in fact no guarantee on cds or dvds (other than ones that are actually printed - like movies etc.) Some may last only 16months.

iT may be best to make extra backups and store them (in cases upright)
in dark temp controlled places. Or do a net search on archiving cds etc.

Im also putting all my family photos and movies on cd & dvd, and I was surprised to find out about the short life of these things.
(Theres also the inevitable format change too)
Petr

Subject: RE: BS: Sound recording to Computer?
From: Stilly River Sage
Date: 08 Jun 06 - 11:46 AM

This is actually a tech thread and could merit the "tech" prefix and moving upstairs. One of the clones might then even associate the related threads on recording and devices so you can read through them. There have been a lot of very useful tech threads on this and/or closely related subjects. Good luck--

SRS

Subject: RE: BS: Sound recording to Computer?
From: MartinRyan
Date: 08 Jun 06 - 11:56 AM

Coincidentally, I need to move some sound files from mnidisc into a PC. Again, some direct link via USB would probably be most convenient.

Regards

Subject: RE: BS: Sound recording to Computer?
From: JohnB
Date: 08 Jun 06 - 01:14 PM

I would suggest that you keep the original copy as a "wav" file. You can always crunch it down to an MP3 later if you wish.
There is a free downloadable programme called "Audacity" with which you can do all sorts of editing. You can export your final files as ".wav" and with a downloadable add on you can also do MP3's.
I'm not sure what you need to link pictures and sound files together, although I have done it to make a slide show with music in the background, I don't remember which programme I used.
Lastly, although this is only speech and not particularly demanding, go for the best equipment you can afford. You will in all probability never get another chance to do it better at a later date.
JohnB

Subject: RE: BS: Sound recording to Computer?
From: Grab
Date: 08 Jun 06 - 01:19 PM

A basic computer mic will be fine. You can get one that talks USB, or you can get one that plugs into the mic input on your PC. USB is overkill - the basic ones are usually cheaper and the same quality. Every PC that can play sound will also have a mic input. Usually there are three headphone-type connectors next to each other, where one is mic in, one is line in (eg. from hi-fi), and one is line out (eg. to hi-fi or headphones).

Voice can be *massively* compressed. Music MP3s usually want to be at least 128Kb to be decent quality, which amounts to about 2 minutes per MB of storage. Voice, you can get away with as little as 16Kb and hear what they're saying - 32Kb would be quite acceptable to accurately record their voice, so 8 minutes per MB of storage.

WMV (Windows Mediaplayer format) is usually a bit better than that, although you're more at the mercy of what MS decide they want to let you do with your files today. Also you can often play MP3s on newer CD and DVD players, but I don't know of any CD/DVD players that'll do WMV.

Software-wise, I use a free program called Audacity (http://audacity.sourceforge.org) to do all my recording. It's a little more complex to set up so that it can write to MP3, but it comes with full instructions. As previously mentioned, you might as well save directly to MP3 (or WMV or whatever) - you don't need to save as WAV and do the conversion manually afterwards. It's not the easiest program to drive though, so you might want to spend a few quid to get something that's more intuitive. SoundForge and Total Recorder are both decent bits of kit and reasonably priced. Or it's also worth checking PC magazine coverdisks - if you're lucky, they might be giving away a recording program (companies give them old versions to give away on coverdisks, in the hope that readers will upgrade to the newer paid-for version if they like it).

Graham.

Subject: RE: Sound recording to Computer?
From: The Fooles Troupe
Date: 08 Jun 06 - 07:04 PM

"you might as well save directly to MP3 (or WMV or whatever) - you don't need to save as WAV and do the conversion manually afterwards."

This is a 'lossy' storage method - if you need the full quality, especially for mixing purposes, stick with a 'non-lossy' format such as WAV so that you keep all the information for best quality.

Subject: RE: Sound recording to Computer?
From: Bernard
Date: 08 Jun 06 - 07:43 PM

With respect, MP3 for speech is perfectly acceptable at 128k, which is the default 'standard'. Once you go down to 56k, the twittering becomes more obvious.

The BBC (radio) store all the recorded station output as MP3, and all news items, even the music played and pre-recorded programmes, are all stored as MP3 (except where played direct from a CD).

It's worth bearing in mind that a 16 bit .WAV file will be about 10 times the size of the equivalent 128k .MP3 file, yet the difference in quality will be negligible to the average listener.

To be brutally honest, if you're prepared to accept the quality of a photograph (.JPG?) that is only around 400k in size, then you won't be the slightest bit bothered by a slightly lossy MP3, even at 56k!

Subject: RE: Sound recording to Computer?
From: GUEST
Date: 08 Jun 06 - 09:17 PM

Found it. The thread moved. Looks like I'll be able to find lots of other information here too. I've read the comments and thank you all. Another option my niece mentioned today was using a 'digital tape recorder' for the family members to carry around and speak into. I guess, if it had a line out, I could then line in the thing to the computer. With a USB or RCA pin. Then edit it.

Thank you very much.

Grateful Guest

P.S. -- Here's an example of the type of photo I'm saving. Me petite granny, fresh in from the market. A wee Scottish lass who changed her shopping habits a bit when she came to the states. I compressed the heck out of this to upload, but it still takes a moment open.

http://mail.moment.net/~michael/Granny.JPG

Thanks again.

Subject: RE: Sound recording to Computer?
From: Grab
Date: 09 Jun 06 - 12:20 PM

Foolestroupe, if you're using a computer mic, the quality will be such that the effects of the MP3 conversion are utterly insignificant. Computer mics are acceptable quality for voice, but you wouldn't use them for proper music recording. And at 56Kb, the "lossyness" of the MP3 format will be a fart in a hurricane compared to the effects of the microphone.

Also there's the size issue. 400K will give you a recording time measured in seconds not minutes.

Graham.

Subject: RE: Sound recording to Computer?
From: JohnInKansas
Date: 09 Jun 06 - 01:52 PM

A very minor quibble with the Every PC that can play sound will also have a mic input.

This is not necessarily an absolute truth. Most PCs that can play sound probably will have a mic input, but some with "motherboard" integral soundcards may not. It's not something that's really common, but it does happen.

Off the issue at hand perhaps, but many more PCs that have pretty good soundcards, whether "integral" using chips on the motherboard, or plugin cards, have omitted the MIDI jack to make room for multiple speaker jacks, and in some cases the alternative of using the "joystick" port with an adapter doesn't work because of mouse conflicts. Sometimes one can switch to a USB or IR mouse to free the serial (joystick/mouse) port to get a MIDI device to hook up, but it can be a hassle.

Most PCs that have a "real" soundcard will have at least one mic input; but beware of the exceptions - which are NOT necessarily "spec'd" in the description of the new machine you're about to buy.

John

Subject: RE: Sound recording to Computer?
From: GUEST,DB
Date: 09 Jun 06 - 02:32 PM

I've got a little Olympus DM-20 digital voice recorder - and I love it!. I took it on holiday to Slovenia, last year, and recorded such things as crickets, church bells, sheep bells and my own musings. On returning home I transferred the the files to my computer (via a USB cable) and then dumped them on to a CD to complement the CD of digital photographs that I took on the same holiday.
I use the same recorder for songs - but plug a little Sony microphone, on a table-top tripod, for that - again, it works fine for my needs.
I suppose that such a device may be a little over the top if you are able to sit the aged relatives in front of the computer - but if you need to record the relative away from the computer - ideal!

Subject: RE: Sound recording to Computer?
From: GUEST,Grateful Guest
Date: 09 Jun 06 - 08:39 PM

I appreciate the continued input from all of you.

Yes, I was planning on just planting the people by the computer and letting them talk, but this "contraption" discomfits some of them. I'm starting to think a recorder might be best, then transfer.

I've been researching "archival" CDRs the past couple days, and that's been an eye-opener. Now I need to do a crash course on format and decide on what I can store and compress, etc., and then decide on a recorder or not, microphone, and all that.

This computer has standard soundcard stuff, nothing special, but then it shouldn't take much to do what I described. I just need to get up to speed on the sound capabilities of the computer. Shouldn't need to upgrade to do simple voice recordings.

Again, thanks for everyone's input.

Subject: RE: Sound recording to Computer?
From: The Fooles Troupe
Date: 09 Jun 06 - 09:14 PM

Life is full of compromises... :-)

Subject: RE: Sound recording to Computer?
From: robomatic
Date: 09 Jun 06 - 09:37 PM

You can take old tape recordings and feed them from your headphone jack out to the 'line in' input of your computer. You need to adjust volume for maximum effective range of your computer recording software. Some years ago I bought CoolEdit Lite and it's a wonderful intuitive program. I have done little actual recording direct to computer, my main concern with that would be to maintain consistency in mouth-to-mike difference and other typical recording concerns.

As for inputting it into wave format, if you are simply recording monologue, I guess Mono, for speech you needn't sample at higher than 20,500 KHz. This will give you a .WAV (WAVE format) program which uses about 2.5 megabytes of memory for every minute. You can convert it to mp3 format using Apple iTUNEs amongst other programs, and using the custom selection and selecting 128 kByte/ sec stereo rate with VBR and MONO checked will result in a 64 kByte rate which will use about 0.5 megabytes of memory for every minute still sounding very good. In fact, you can probably select 64 kByte/ sec stereo rate with VBR and MONO checked which will give you 32 kByte rate which will use about 0.25 megabytes of memory for every minute and still sound good.

Subject: RE: Sound recording to Computer?
From: The Fooles Troupe
Date: 09 Jun 06 - 09:43 PM

78 rpm recordings sounded OK until newer techniques came along because there was nothing to compare the recording technologies with, UNTIL the new technologies appeared (a tautology, I know!) and THEN there were wails about 'the permanent loss of sound quality in old recordings'...

Subject: RE: Sound recording to Computer?
From: GUEST,Grateful Guest
Date: 23 Oct 06 - 12:12 AM

Just an update on this topic.

I discovered the two computers I have primary access to use Windows XP, which has a program called Sound Recorder. Start > Programs > Accessories > Entertainment > Sound Recorder. If it's not there, do a Search of 'sound recorder,' and it should turn up (right-click to put an icon on your desk top)

Sound Recorder is a small oblong box. Under File > Properties > Convert Now, you can select a recording level. I selected 48.000 kHz, 16 bit, mono as my level and saved it as a pre-set.

Simple microphone plugged into the back of the computer, next to the speaker out. Cheap old mic from the early days of chatline talking. Tissue baffle over the mic to prevent the percussives from distorting.

Sound recorder, just click the red circle to start recording. 60 seconds of recording time, though you can extend it indefinitely by stopping the recording short of 60 seconds, then clicking the start again...an additional 60 seconds is added to whatever you've recorded so far. Seems to be indefinite time limit.

Then I Save As and give the file a name.

As for compressing to mp3, I found an easy, flexible and free program online. CDex. Free download can be found here:

http://cs-netlab-01.lynchburg.edu/users/anonymous/MP3Conv/WavToMP3.htm

I experimented on different compression rates and finally settled on 64kbs. This gives me a compression rate of 10 or 11:1. That's acceptable, as far as storage space available, and I honestly can't tell the difference between the .wav and the mp3. Very good, clean sound for voice recording. Compression rates can be set by opening the CDex window, then going to Options > Settings. Select your presets, click OK.

I keep a CDex icon on the desktop too, so from recording to compressing, I just click a couple of icons and type a file name. Both the Sound Recorder and CDex keep my presets as default, too (or they have so far), so I don't have to refer to all the setting adjustments I made note of when I found the optimum settings.

Haven't decided how to handle the remote stuff yet, but now I'll be able to get cheap mics and show the younger folks in the family how to run Sound Recorder, to collect family anecdotes. I can collect them on CD-RWs from time to time and compress them as time permits. That's the plan, at least.

Thanks again for all your assistance.

Subject: RE: Sound recording to Computer?
From: Terry K
Date: 23 Oct 06 - 03:00 AM

I don't understand the concern over CD degradation - surely you would have the master archive stored (backed-up) on a remote hard drive, from which you make new CDs whenever you like. That way you can archive in the most expansive format and convert down at the time you burn to CD.

Subject: RE: Sound recording to Computer?
From: treewind
Date: 23 Oct 06 - 03:52 AM

Use sound recorder if you really want to (and click the start button every minute...) but Audacity does it much better and is FREE. (and quite a small download).

With regard to file sizes,
.WAV needs 10 Mbytes per minute
(CD quality: 16 bit, 44.1 kHz sampling rate, what people usually mean by .WAV)
.mp3 at 128kb/s needs 1 Mb per minute i.e. 1/10 of a .WAV file.

Audacity reads and stores in either format and can convert.

Anahata

Subject: RE: Sound recording to Computer?
From: GUEST,Grateful Guest
Date: 23 Oct 06 - 01:32 PM

Right.

But Sound Recorder is included on all Windows XP machines. Pretty much universal now. Audacity would need to be loaded onto the computers. Some of the family aren't on the internet, but they do have XP. So, with Sound Recorder, I can standardize the instructions for the entire family and get decent sound quality.

As far as compression, I couldn't locate a free version of Audacity. Some free TRIALS, but that was it. So I found CDex and went with that. Totally free, easy to use, lots of range. I'm sure Audacity is better, and if someone wants to post a link to the free version I'll look at it.

As far as sound quality and size of files, I'm happy with what I'm capturing and converting. These are just snapshots of people's voices...recordings that will allow people in the future to match up faces with voices. And the recordings at the settings I described are quite lifelike and not "lossy" after conversion.

Sure, I'll save the .wav files to CD-R, but the compressed files will be circulated (on disc) among family with scanned photos, obituaries, etc.

I know this is an endless debate, but in the final analysis we all have to go with what meets our criteria. What I've described will do the trick.

Thanks again.

Subject: RE: Sound recording to Computer?
From: Grab
Date: 23 Oct 06 - 02:03 PM

There *is* no paid-for version of Audacity. It's free software. If you're having problems getting hold of it, it's at:-

http://audacity.sourceforge.net

If 60s is enough for what you'll be doing, I'd be surprised - I've yet to find a story worth telling that'll fit into 60s! ;-)

Graham.

Subject: RE: Sound recording to Computer?
From: IvanB
Date: 23 Oct 06 - 02:21 PM

Grateful Guest, your relatives wouldn't need Audacity loaded on their computers to hear the files you record. Any software capable of playing back wav or mp3 files woyld be sufficient. Windows Media Player (free with Windows, but there are better alternatives also) will do the job. There are also free programs out there which would allow you to 'link' a sound file to a picture so the recorded sound bite would automatically play when the picture is viewed. Lots of possibilities, and they don't take too much computer savvy either.

Subject: RE: Sound recording to Computer?
From: Declan
Date: 23 Oct 06 - 02:25 PM

Martin,

No one seems to have answered your query above. Its a while back so you may have got some advice by now, if not the following may be of use.

The more recent Minidisk players allow you to hook up your player by a USB connection. With this you can transfer the files digitally without loss of quality. If not you can take hook a connection between the head/earphone jack on your MD player and use recording software to transfer it onto the computer. This will be an analogue connection which means (a) it will take as long to record as it does to play (digital transfers will be a lot quicker) and (b) you may lose quality in the recording process.

Subject: RE: Sound recording to Computer?
From: oggie
Date: 23 Oct 06 - 02:26 PM

You can never have too many formats of storage for anything important. Even hard drives fail (as a family we've got through 5).

I store wav files on DVDs, mp3s created from them on CD, and use an external hard-drive for everything.

As far as sound cards go, not all sound cards are created equal and if youare doing more complicated recording then latency can be an issue. Sound on Sound have some articles on this which should be on their website (sorry haven't got the link to hand).

Samson now do a USB Condenser mike for around £75 which seems to work quite well. My son and I have recorded melodeon and whistle with it and the results are fine. Syncing with keyboards and sof-synths was harder but possible using Steinberg.

All the best

oggie

Subject: RE: Sound recording to Computer?
From: GUEST,Grateful Guest
Date: 24 Oct 06 - 01:30 PM

I have a followup question to the one about doing my own recording.

In my research, I stumbled across OTR (Old Time Radio). Lots of sites out there devoted to it. And they all advertise various things, but it seems to come down to people making their own recordings (transfer from reel to reel tape or transcription discs), transferring these to computer, then compressing into mp3 format, then putting the shows on disc to sell.

32kbs seems to be standard for most of the compressed shows (100 half-hour shows on a disc), but some of the sellers offer 64 kbs, 128, etc. But some swear there's no discernible difference. I don't know. No experience.

Any opinions on this? On possible differences in sound quality?

Subject: RE: Sound recording to Computer?
From: treewind
Date: 24 Oct 06 - 02:21 PM

Old time radio eh?
32k MP3 would be about right if you want the quality of a 1950's firebottle-powered AM radio.

64k isn't too bad if you keep it mono.
128k is about as good as FM radio - not perfect, but listenable.

I think most people could tell the difference very quickly on a straight comparison.

Anahata

Subject: RE: Sound recording to Computer?
From: Bernard
Date: 24 Oct 06 - 03:55 PM

A tip for anyone wanting to record on to their PC...

Before you record anything at all, do a silent recording first.

Wot?!

Don't plug anything in at all, and record the sound of the sound card on its own. You may be unpleasantly surprised by the amount of digital noise.

If such noise exists, it is virtually impossible to correct, either before or after recording. As the noise is probably inherent in the PC, it can be like finding a needle in a haystack!

Possible solutions...

Try a different sound card.

Try moving the sound card to a different PCI slot - away from the video card. Okay, if it's an onboard card and onboard video, you're stuffed! One of my PCs has that problem.

So... try a different PC!!

There are lots USB devices around now that you can use instead, some really cheap, others not.

Some software (Cool Edit/Adobe Audition, for example - Adobe bought Cool Edit from Syntrillium) will allow you to use the 'silent' sample as a template for noise reduction, but there is usually some degredation of the signal you want to keep as well.

The setup I use for our Radio Britfolk programmes has an M-Audio Delta 1010 in a fairly elderly PC. This has a very simple sound card, with outboard inputs and outputs housed in a 19" rackmount. There are 8 line inputs and 8 line outputs, and it is beautifully clean. The card also has co-ax in and out SPDIF sockets, which I can use with my Tascam 788 HDD recorder.

The PC doesn't need to be all that quick by modern standards, mine is an AMD Athon 1.15 with 512 memory, running XP SP2. It has a 300Gb primary drive, a 200Gb secondary, and two LiteON CD burners.

The software I use is SoundForge, which is quick and easy when you get used to it...!! I much prefer it to Cool Edit and Audition, which I also have. I was allowed a cheap upgrade to Audition, as I had a registered version of CoolEdit 2000... interestingly it allows me to have both concurrently on the same PC.

When Ali and I used to do 'Sounds of Folk' on BBC GMR, I had access to Quick Edit Pro, which is part of the RadioMan suite. It was good, but rather clunky to use - and it didn't properly follow the Windows conventions with filenames, etc., which made it rather hit-and-miss. The worst part was it created a new file each time you did a 'save to database', and very few users had delete permissions... Understandable on a live radio station, I suppose, but a pain nonetheless!

I could bore for England writing about this lot... if there's anything of interest, then fine - if you'd like to know more, ask.

Subject: RE: Sound recording to Computer?
From: bobad
Date: 25 Oct 06 - 09:16 PM

Does anyone know if it is possible to record a kitchen table sing around directly to a computer and get decent (not necessarily audiophile quality) results and if so what kind of mic would best do the job?

Subject: RE: Sound recording to Computer?
From: The Fooles Troupe
Date: 25 Oct 06 - 09:47 PM

Actually - one of those 'surface mics' - a flat plate designed to sit on a table surface is intended for 'conferences' - but any thing that touches/bumps the surface will be recorded too...

Subject: RE: Sound recording to Computer?
From: Bernard
Date: 26 Oct 06 - 02:14 PM

No need to buy a plate mic (or more correctly a 'boundary mic') - lying a tieclip mic on its side on a table will do the same job, because that's all a plate mic really is!

Subject: RE: Sound recording to Computer?
From: Darowyn
Date: 26 Oct 06 - 03:22 PM

"No need to buy a plate mic (or more correctly a 'boundary mic') - lying a tieclip mic on its side on a table will do the same job, because that's all a plate mic really is! "

Oh no it isn't!

The capsule is in a little cavity formed between the plate and the flat surface you put it on. Sound enters from all sides and the pressure in the cavity rises and falls accordingly. The mic diaphragm moves as a result.
That's why the thing you call a plate mic is referred to as a PZM as well as a boundary mic. Pressure Zone Mic- from the pressure zone cavity.
Cheers
Dave

Subject: RE: Sound recording to Computer?
From: Bernard
Date: 26 Oct 06 - 04:45 PM

PZM is Crown's trademark...

The cavity effect on a microphone decides whether it is omni, cardioid or hypercardioid. It has nothing to do with the boundary effect.

The noise cancelling on a boundary mic is determined by the difference in signal between direct and reflected sound, and the flat surface upon which it is mounted is the 'boundary'.

The way it works is to shorten the delay between direct and reflected sound.

In 1978 sound engineers Ed Long and Ron Wickersham recognised the effects of a boundary layer in sound recording. In studying the behaviour of flushmounted microphones, they discovered that within a few millimeters of a large surface, sound levels from a pair of equal level signals add coherently because, in close proximity to the surface, the particles are still in phase as they accelerate after being brought to a stop by the boundary, thus creating what is called a pressure field, or pressure zone, in the boundary layer.

The result is a 6 dB increase in acoustic pressure.

In this pressure field, the instantaneous pressure is uniform in all directions, with no direction of propagation. A microphone diaphragm will therefore have 6 dB higher sensitivity when placed in the pressure zone than an equal microphone placed in the free field. Diffuse sound will not be reflected at a plane boundary because diffuse sound has no direction (per definition). This microphone will therefore give direct sound 3 dB higher level than diffuse sound. If used outdoors, these microphones will perform better than conventional microphones with regard to wind noise, as the wind velocity in principle is zero on the surface of the ground.

The pressure zone can be defined another way: The pressure zone is the distance from the boundary that the microphone diaphragm must be placed to achieve the desired high-frequency response. The closer the diaphragm is placed to the boundary (up to a point), the more extended is the high-frequency response.

Subject: RE: Sound recording to Computer?
From: GUEST
Date: 26 Oct 06 - 06:42 PM

Could a plate mic be suspended, to eliminate the table-bumping issue? Hang it with a a drilled plate above it. Suspend it over the group sitting in a circle, sound goes up, bounces off the plate, into the mic. Just a thought.

Subject: RE: Sound recording to Computer?
From: Bernard
Date: 26 Oct 06 - 07:05 PM

A plate mic depends to some extent (according to design) on the surface upon which it is placed. Mounting one on a suspended plate or board should work perfectly well.

When installing them as ambience mics for induction loop systems, I try to mount them on a wall or ceiling. I tend to use the AudioTechnica ones - which are now 'mobile phone resistant'!

I also install them fairly often in churches on the main altar, and 'table bumping' isn't usually a problem.

Subject: RE: Sound recording to Computer?
From: GUEST,Grateful Guest
Date: 01 Nov 06 - 11:53 PM

One of the ways I've found to put computer recording to use. At the bottom of my eBay pages. See if it works, copy and paste:

Click HERE for an audio tip from the seller. (19kb)

If any of you want to use this on your eBay pages, feel free to. I may change the URL in a couple of months though.