Subject: Re: [AUDITORY] Tweeters for noise trauma From: Bob Masta <audio@xxxxxxxx> Date: Thu, 11 Feb 2021 08:46:46 -0500Speaker specs are always given at 1 meter distance. Animals being exposed= are usually much closer. Note that this can cause its own problems if you are trying to expose mult= iple animals using multiple close-by speakers, which will create interference patterns. With noise stimuli, I have been able to reduce that problem som= ewhat by using two unrelated noise sources to drive alternate tweeters in the ar= ray. Another issue is that the animal will move around in its cage, and may thu= s move out of the main beam of a close-by speaker if it has space to do so. Since you mentioned mice, I expect you will be working above 20 kHz. Twee= ter frequency responses tend to be very ragged in this region, probably since = they are made for humans(!). Be sure to get curves for the models you are interested in. Also note that simple speaker power-handling specs can be misleading in a = major way, if they assume that the speaker is used to reproduce music, and they = state the power applied to a full-range system that uses that tweeter. Assuming= a pink-noise power distribution that falls at 3 dB/oct, with the woofer usin= g the most power, the tweeter gets very little. You may have to contact the maker directly for relevant data. High-power tweeters tend to be expensive ($40 US seems to be typical at www.parts-express.com these days). The last time I set up a system to do = this was 2007. I ordered one each of 2 prospective models and ran my own tests.= I think they are out of production now. The Pyramid TW47 was the one I chos= e. It hit 121 dB SPL at 9 inches driven by 4 Vrms in 1/3rd octave around 10 k= Hz, or 118 dB with a full octave at 16 kHz. Hope this helps! Bob Masta ------------------------- On 11 Feb 2021 at 11:12, Boris Gour=E9vitch wrote: > Dear auditory list, > > I was looking for a speaker (probably a tweeter) that would reach 120 to= > maybe 130 dB SPL in a high frequency range (for mice). > > I am a bit puzzled with the many papers inducing noise trauma (i.e. > Warren, Fenton et al, J Neuroscience 2020; Amanipour et al, 2018; Chen, > Sheppar and Salvi 2016; Novak, Zelenka et al, 2016) which actually used > pretty common tweeters to do that. Technical specifications for these > tweeters do not really indicate that they could handle such high SPL > (and therefore such high voltage). How did they determine that ? How can= > we know then ? Only by sensitivity measure adjusted for the watt power > of the speaker ? > > Let's take an example: in the Warren et al above cited, the Visaton > speaker from RadioSpare is used to deliver 3kHz at 126 dB SPL. The > technical specifications > (https://docs.rs-online.com/170c/0900766b802e5b23.pdf) indicate 30W max > and a sensitivity of 86 dB. Thus, it seems that this speaker could not > deliver above 101 dB SPL. How did the authors do to avoid damaging their= > speaker ? > > Same question with other speakers as well. I'm not an > acoustician/electronician and I am probably missing something here. > > Many thanks for your help. Also, many of the tweeters from the papers > above are discontinued so if you know a pretty robust one that you are > safely using at high SPLs, please do not hesitate to tell me. > > Best regards > > Boris > > -- > Dr Boris Gour=E9vitch > CNRS Researcher > > Institut de l'Audition > UMR1120 Inserm, Institut Pasteur > 63 rue de Charenton > 75012 Paris, France > > Tel: (+33) 1 76 53 50 41 > > Personal Web page: http://www.pi314.net/ > > > -- > L'absence de virus dans ce courrier =E9lectronique a =E9t=E9 v=E9rifi=E9= e par le > logiciel antivirus Avast. https://www.avast.com/antivirus