Bia and Ingrid performing a classic

Yesterday, Bia and I rehearsed a song and recorded this video. I was really pleased with the result being this the first take. Hope you enjoy it!

Tapping Machine Calibration

Tapping Machine Calibration

This week I had to check if some tapping machines were under the standards.
The curvature of each 5 hammers were taken 10 times. Moreover, the diameter and its perpendicular were taken in the top and 30mm below. So the probability and standard error could be calculated.

Just having fun

Sometimes when I have free time I go to Adelphi Building, ask for room with a piano and just have some fun. This short video is a good result of one of my goings there.

Absorption coefficient measurement

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I have worked really hard this week. My boss had loads of carpet tiles to test and measure their absorption coefficients. Although I ended up really tired, I can’t complain. I learned a lot!
The first samples of carpet were needed to preconditioning (required by the client). So they were layed down in the ground waiting for 20 hours to be tested.

The procedure to measure coefficients in the reverberation room always starts with taking the temperature, humidity and atmospheric pressure. In this case twice: when sample in and when it is out. Then the reverberation time to this conditions is measured using 6 microphones and two sources. After that, the carpet tiles are placed together in the room with an area about 12 m2. Then, reverberation time is taken again. Then by the difference of the RTs, absorption coefficient of that sample can be calculated.

Anechoic Room and me singing

So the last post was me singing in the reverberation room. I was really curious about the difference I would feel singing in the anechoic room, so I did another video. I know that was not accurate because reflections came from me holding my mobile, but I could feel the sound really dry and much more imperfections (oh hell, where is the reverb to “save” me?!).

Some vital statistics about the anechoic room of Salford:
*Background noise level -12.4dBA (some say is the most silent room in the world)
*Working area 5.4x 4.1x 3.3 m
*Cut-off frequency 100Hz

Reverberation Room and me singing

I love reverb. Of course it masks my detuning, but also makes me feel bigger when I sing. I think maybe I discovered why I have so much fun making tests in my placement: I can sing “whenever” I want and really enjoy it.
The receiver room in the reverberation room in the University of Salford has a reverberation time of 3.4s in the mid frequency. So I did this video, because I wanted to know how much was this RT for my ears.

Noise of vacuum cleaners

Noise of vacuum cleaners

Some companies require the service from our acoustic laboratories. When talking about machines, vacuum cleaners and washing machines are the ones most sent to test. The noise that it produces is measured in the range of frequency between 100Hz to 1kHz, then checked if they are adequate to the British Standard.
The process is quite simple and fast. What takes most time is to set up the equipment (microphones, cables, positions,…). First, a X, Y and Z axis have to be established in the semi-anechoic chamber. Then, all the microphones should be in the right position so that it creates a semi-sphere over the machine that will be measured. The microphones are calibrated and should be pointed to the vacuum. Temperature, humidity and atmospheric pressure are taken. Later the vacuum cleaner is placed over a carpet (1x1m) in the centre and positioned according to the british standard (each type of vacuum has a different pattern). Finally, sound pressure level in each frequency is measured by each microphone and data is stored. This information is essential in order to sell the product. So the more quiet, more the client will be pleased.

My voice and GraphicMail’s Quick Tour

I love sound that is why I chose acoustics engineering in Salford. Although my biggest passion is voices. Since I was a child I loved to sing and I have been “practicing”. I rarely use it as a professional way, but this week an advertisement was finalised. It made myself really proud, because I was the voice representing GraphicMail in Brazil. So I hope you enjoy as much as I did.

GraphicMail, go beyond inbox!

Sound Insulation Tests

Sound Insulation Tests

This was my first week at work! Being new, all the rooms in the labs were introduced to me as well as my team and issues about workplace. I couldn’t be more excited and eager to learn in this environmental.
When I arrived there, Sound Insulation Tests were already happening and I could watch and learn loads in the procedure.
The reverberant room is composed by the receiver and the source room. In between these rooms the material that is going to be analysed (in this case double partition glass with air in between) is installed and measured its capacity to reduce the noise.
In the process, white noise is turned on in the source room in a high sound pressure level. After that the noise that reached the microphones in the receiver room is studied in a range of frequencies.
Of course, accounting frequencies is really important. First, resonant frequency and coincidence should be considered. They are peaks in the soft curve of sound attenuation. Then, as the lengths of the waves vary along the frequency, if there are leakages, high pitches would be stronger that they should be. Unfortunately, leakages in the frames are really hard to stuck, but effort to make it the least is needed.
Afterwards, knowing how much the sound reduction index that installation could provide, the glass is taken out and installed again but in a different way (e.g. boards in the frames, foams in the frames, another stews,…). Then all the tests are repeated.

That was my first week!

Got Laboratories in University of Salford!

Got Laboratories in University of Salford!

At the end of my exchange program, I am supposed to have either a placement, or a research. I particularly didn’t want a research, because as I don’t have any experience in acoustics, I wanted something more empirical. So, on this past Friday I met with Professor Andy Moorhouse and got the happy news that I will start to work in the acoustics laboratories next week!
I couldn’t be more pleased!!!