Recent content by MatthewDougherty

I got into this research problem when I was transferring a song from 78. Recorded in 1933, the song, Blue Danube by the Vienna Philharmonic, was later re-issued by various publishing companies onto 33, 45, & CD; which I transferred into Adobe Audition for comparison. For 78, 33, & 45, I...

This contains matlab code for computing the absorption coefficients using two microphones. https://ideaexchange.uakron.edu/cgi/viewcontent.cgi?article=1707&context=honors_research_projects https://github.com/nathanpalella/IT_absorption/blob/master/absorption.m

a useful reference Deshpande, S. and Rao, M. (2014) Development of a low-cost impedance tube to measure acoustic absorption and transmission loss of materials. In: 121st ASEE Annual Conference & Exposition, June 15-18, 2014, Indianapolis USA. Paper ID#8776 The diameter of the tube seems to be...

That is how I read their paper, they should have upgraded to multi-input capture. Why they did not, and went with a more expensive method, is a mystery. If they had used REW rigorously, comparing it to Holmarc results, the paper would have had a wider useful impact and provided broader testing...

1) Research thesis using REW with an impedance tube https://opus4.kobv.de/opus4-filmuniversitaet/files/267/FaciusBA.pdf 2) A related REW post ttps://www.avnirvana.com/threads/using-rew-to-measure-sound-absorption-in-an-impedance-tube.3569/ 3) A previous attempt indicating a problem using...

quite a stack of speakers. How loud do they get? In the 1980's I was in bldg 49 at JSC/NASA, the vibration & acoustic test facility, originally built for Saturn 5 rocket tests. The many horns were 30-50ft long. It could get to 200+ db. When rocket size doors were open birds would get in. If...

the google translate did not completely make sense. I'm willing to spend, I can make something like a "Kundt tube", I'm willing to buy a license for multi-channel measurements... Is there any literature I should read before I start? )) I think you are asking the same question I have: will this...

I was thinking using a 1ft diameter HVAC duct pipe, a studio monitor with a known frequency graph, and two reference mics (one in front of the material, one behind). Using several materials with known absorption coefficients, get their profiles using REW. Then use materials with unknown...

Has anyone used REW to calculate sound coefficients for walls? Generally, acoustical theory puts sound into three categories when striking a surface: reflection, absorption and transmission. When analyzing an empty room, REW will tell you a lot about the reflectivity of the room, but nothing...

no offense taken. I shower naked and sometimes sing in the rain. I appreciate your help. Acoustic engineering is a new thing to me. There is something going on with the room, and it might only be people are enamored with the room's shape; and are ignorant they are ok with 8-bit 16-khz audio...

thanks for the insights. What you are saying is consistent with what I have read elsewhere. The room is intended for visual fulldome production, so I am not put off by the acoustics. Still confused why people are showing up wanting to listen to music for hours at a time, it is just an empty room.

Could be, not familiar with the speaker. Reading this http://www.audioheritage.org/html/profiles/jbl/paragon.htm, Ranger notes "keener appreciation of all the instruments", something I am noticing, the room is the speaker, walking around the room I can pick out the instruments as though I was...

I can imagine. Large domes produce large focus reflections that amplify echoes. But smaller domes are within the Haas effect, causing people to react differently. People gravitate to the center to talk or sing, but I know there are some modal frequencies I would like to attenuate. I have two...

In some ways I am having fun, other ways I am lost in a forrest. I am a newbie on this trying not to get stuck on rabbit trails. When the new 9.2 receiver w/ Dirac comes in I will do the measurements again. This should improve sound played in the room. With the 7.2 system I have now, the...

I worked with them for eight years using their mobile domes at conventions, as a collaboration when I was doing electron microscopy molecular visualization. How I got the bug to build my own for optical research and doing content they won't touch, particularly art, experimental, and history...