How much acoustic power you need? Short distance or far throw? The AMT tweeter used in ADAM studio monitors is quoted as operating up to 50kHz. The Pi connected to an audio "chip" amplifier connected to a wide bandwidth tweeter would be a reasonable approach for a variable frequency ultrasonic setup. There are caveats of course, but it all depends on what you're trying to do.
I'm trying to scare off animals with a 25khz-50khz SHORT distance throw. Maybe 10 foot max.
Okay, I was fooled. Buchanon is another spammer
I am not a spammer, sorry for not responding sooner! I'm just trying to digest this stuff as I'm a complete audio noob.
Firstly it requires a bigger amplifier than ceramic transducers and will not work driven directly from a GPIO output.
I'm still trying to understand the relationship between power/voltage, sound volume, and frequency. Frequency controls pitch, where as putting voltage into the system controls volume?
To reduce the chances of burning out the tweeter there are three things to watch.
1. Do not drive with ultrasonic continuously but in short bursts. For example, a 200ms burst every 2 seconds reduces the heating by 90% but should still squeak the sh** out of squirrels.
2. Guard against DC and all low frequency’s below, say, 10kHz with a high-pass filter. All this energy would be turned directly into heat.
3. Never drive the Tweeter directly with square waves, either from the output of the pi or due to clipping in the amp. This could be achieved with a low-pass filter set @ ~50-60kHz. A square wave will produce about 1.4 times more heat than a sine wave of equal peak magnitude.
#1 Makes a lot of sense.
#2 I don't plan on using this at low frequencies like that, but I will read up on high-pass filters which I'm unfamiliar with.
#3 Just read up on this as well, and it also makes sense about square waves driving more heat.
Thank you all for the responses, I'm just trying to figure this all out myself as well. It sounds like I'll need a power source of some time and many more hours of reading.
We've been having similar ideas for quite a long time now, and we are in fact working on something very similar to what you propose which will allow people to provide annotations for sounds in Freesound. We'll announce it when ready, probably in the coming months.
Thanks for the comment
Are there any females that are willing to do a female vocal tag saying, RickyMac Beatz. Whoever is interested I'd appreciate it greatly. Maybe In return, there is something I could do for you as a producer. I'll leave it up to the person doing it to get creative with it. As Long as the vocal tag contains RickyMac Beatz. Thank you very much in advance. You can easily get ahold of me at email@example.com.
I got you, no problem. I'm not pretending to be a part of Freesound staff but I just wanted to point that I'm a part of the community sound creators and that I was just proud of it.
Then, I don't want to bring any issues and I will NOT use the official logo on my Facebook account, YouTube videos or whatever.
Many thanks for the answers
I d'like to talk with you about something that could really improve the quality of freesound database and takes advantage of the big community of people that we have here. For me, there is a lack of tool for describes the sounds uploaded. I mean, It could be really great to have a system that allows listeners to describe the sounds by themself since it's only possible for the moment to leave a comments and rating.
For example, a very intersting thing should to allows the people to define if the sound is : monotonic, polyphonic, not tonal, etc and even to give the note (or the frequency?) if it is monotonic, to give the key or the chord in case it polyphonic.. etc. To give a tempo if it is rythmic.
In fact, there is a pretty intersting book about this (that surely a lot of people know here) "Le Traité des Objets musicaux" by Pierre Schaeffer but it goes too far a website and it is not user friendly.
What do you think about that ?
a (bad) haiku
Spam comes and goes
I have learned of AMT
Thanks Wibby et al, I learned new stuff!
I would approach the producers you think are his nearest competition and say "my voice was used on this massive dancehall tune, want to collab?" and get them to sign you recording, performing and songwriting rights before you record.
Use this to your advantage.
tath very good
I'm posting this to draw your attention to the special sample request that Bram posted in the forums and which we (the Freesound dev team and moderators) don't want to go unnoticed.
We'd like to ask for your participation, especially the participation of those of you who have been Freesound users for a long time, but also of the newer members of the community.
For those of you who don't know Bram, he started Freesound with Xavier Serra back in 2005 at the MTG-UPF. He did most of Freesound development during the first years and is still a very active participant in the project. But perhaps even more importantly, he has been (and still is) supporting and building the Freesound community during all these years, and greatly contributed in making Freesound what it is today. However unfortunate the circumstances are, let me take this opportunity to thank you Bram for the incredible efforts and energy that you put in Freesound!
My warmest heartfelt thoughts to you and your family.
No recording from me, but I could not have matched the calm and peace captured by klankbeeld anyway.
I hope that over time the experience of having had them in your life will leave positive memories; a gain that will outlast your feelings of loss.
My best regards to you all,
Woops, you're right. "Tee" would be better!
"Thea"? u sure bout that?
I might have a go at this
Can someone make me a (sexy) female vocal tag?
The line is;
"O.T.P productions" (pronounced as OOh-Tee-Pee Productions)
and just a short "O" if possible. (for FX purposes)
I would really appreciate it!
My in menoriam in audio
I thought it was weird that they never responded. Lame..
Okay, I was fooled. Buchanon is another spammer with cut and paste from other blogs with spam links added. I wasted quite a lot of time trying to be helpful with this one, as did dheming, bless him/her/them!
- https://freesound.org/forum/off-topic/40039/?page=1#post88572 Different spam link but same problem!