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Prosound Shootout 2007 [message #28276] Wed, 01 August 2007 08:14 Go to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18677
Registered: January 2001
Illuminati (33rd Degree)

We're all set for the Prosound Shootout on October 19, 2007. Check the link for details:

Test Plan [message #28277 is a reply to message #28276] Wed, 01 August 2007 09:18 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18677
Registered: January 2001
Illuminati (33rd Degree)

The test plan for this year is the same as was used in 2005. I wrote the test plan and did the measurements that first year, but in 2006, David Lee did the measurements with Praxis so the setup and procedure was slightly different.

Schedule and exhibitors [message #28278 is a reply to message #28276] Wed, 01 August 2007 10:17 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18677
Registered: January 2001
Illuminati (33rd Degree)

As in all previous Prosound Shootouts, our main focus is on gathering useful data. This is what is most difficult for people to get, because you need the right environment and test equipment to get it. The environment has to be a large, open space free of obstructions and noise. It has to be a place where you can generate high SPL's that can be heard for miles. And you have to have a good measurement system. So getting this kind of data is important for us.

Secondly, we all want to actually hear the equipment present. Of course, you can listen to the gear in other environments, at gigs and whatnot. So if pressed for time, we'll always get the data first.

Thirdly, David Lee has been a proponent of the workshop approach to events like this. He would like to have a training session, a question-and-answer period where people can discuss issues and learn things like proper use and loudspeaker placement.

We will have the track from 10:00am to 6:00pm. Load-in and setup usually takes about an hour. We may be able to get the track to open the gates a little earlier, say 9:00am. In fact, I'm sure that's OK, maybe as early as 8:00am. If we can all be sure to be there early, it will help us get setup quickly. I usually connect lines to the power distro, setup the amplifier and measurement system and measure out the environment, marking lines on the ground to know where to set the speakers. Each of the exhibitors load out their gear and get them setup in the staging area.

After load-in and setup, it takes about 30 minutes to properly measure each speaker. This is a very aggressive and optimistic schedule though. Sometimes, it can take closer to an hour to move out a set of speakers, move in another set, connect up and do all the measurements. If there are any problems, like a connector won't cooperate or someone finds a speaker is phased wrong, this takes extra time. So we ask that each exhibitor come prepared with speakers that are ready to test and with cables that are easy to identify polarity and connect up to use.

If all goes smoothly, we can be ready to measure by 10:30am and have the first three systems measured by lunch. We'll call in a pizza or have a volunteer grab us all some sandwiches and break for lunch. Depending on our schedule (how many exhibitors are there and things are going), we may choose to stagger lunches so we can keep making measurements through the lunch period. Best case, we can measure six to eight systems in a day.

After we've measured everything, we'll listen to each system. So bring your favorite CDs. Some people have already volunteered to bring tops so we won't be listening to just subs. We probably won't have time to listen to more than one or two songs on each speaker though.

After that, we'll have a question and answer session. David Lee has expressed interest in this, so he will be available for offering his advice. Others may volunteer to do so as well. Discussions always get started throughout the day too, but they are often interrupted by our sweeps. So we'll finish out the day with a question and answer session. If we've exhausted our time, we can always meet in the conference room at one of the local restaurants for this part of the event.

We have really just started taking commitments from exhibitors this week. But so far, we have the following exhibitors that will be present:

Lance Klaurens or David Lee may bring other commercial products to compare with, but it is likely that we will not have time. We may have a full schedule from exhibitors that attend, leaving no time to measure outside gear from companies that don't attend. We'll see.

If you'd like to bring something to be tested, please write to me at webmaster@audioroundtable.com. Currently, we are only performing measurements of subwoofers, but are interested also in having top boxes for the listening portion of the event. We are considering taking measurements of top boxes at subsequent events, maybe next year.


Exhibitor list CLOSED - Here's the schedule: [message #28287 is a reply to message #28278] Mon, 01 October 2007 08:59 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18677
Registered: January 2001
Illuminati (33rd Degree)

Exhibitor's list:

Schedule:

10:00am - Load-in and setup
11:00am - BASSMAXX measurements
12:00pm - Fitzmaurice measurements
1:00pm - π Speakers measurements
2:00pm - JTR Speakers measurements
3:00pm - Outline Audio measurements
4:00pm - Listening sessions
6:00pm - Load-out and go to restaurant


Prosound Shootout 2007 - Weather Forecast [message #28296 is a reply to message #28276] Mon, 15 October 2007 08:52 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18677
Registered: January 2001
Illuminati (33rd Degree)

Weather forecast in Tulsa on October 19th is 80° and sunny.

Perfect!


Re: Prosound Shootout 2007 - RESULTS [message #28299 is a reply to message #28276] Sun, 21 October 2007 12:44 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18677
Registered: January 2001
Illuminati (33rd Degree)

We were blessed with wonderful weather again this year. Sunny and about 65° when we all showed up in the morning, warming to maybe 80° by mid-afternoon.

http://prosoundshootout.com/Photos/2007/Lineup04.jpg
Left to right: Michael Parham, Wayne Parham, Debbie Loughridge, David Lee, Bill Wassilak, Stan Loughridge, Jeff Permanian, Leland Crooks, Harley Dear

http://prosoundshootout.com/Photos/2007/Lineup05.jpg
Left to right: Wayne Parham, David Lee, Steven Parham, Jeff Permanian, Leland Crooks, Harley Dear

Below are photos of the speakers side by side, taken from three different angles. This will help you get an idea of the relative sizes of each box. Click on a picture to show a larger view.

http://prosoundshootout.com/Photos/2007/Lineup01.jpg
http://prosoundshootout.com/Photos/2007/Lineup02.jpg
http://prosoundshootout.com/Photos/2007/Lineup03.jpg
Left to right: (2) BassMaxx X2C Deuce, (2) JTR Growler, (1) Fitzmaurice Tuba 36, (2) Fitzmaurice Titan 48 (with DR250 on top), (2) 12π

The wind was calm in the morning and late in the afternoon, but picked up a little in the mid-afternoon so we measured the noise floor twice, once in the morning and once in the afternoon. This sets the minimum SPL we can "see", so once a sound is below the noise floor, we don't know what level it is. This is important mostly when looking at the distortion charts, because they are (hopefully) down in this range.

Once distortion is below the noise floor, we don't know what level it is. This sets the minimum distortion we can measure. Distortion that's 20dB below the fundamental is 10%, -40dB is 1% and -60% is 0.1%. So since the noise floor is about 65dB to 70dB, the fundamental has to be 110dB for 1% distortion to be visible above the noise floor. See the distortion conversion chart.

http://prosoundshootout.com/Measurements/2007/NoiseFloor.jpg
Noise Floor
Distortion Measurements [message #28300 is a reply to message #28299] Sun, 21 October 2007 12:56 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18677
Registered: January 2001
Illuminati (33rd Degree)

The way we measured distortion is to filter out the fundamental and capture sound in the first two octaves above the fundamental. This gets mostly the second and third harmonic plus any noise present in that band. Since distortion harmonics from subwoofers (especially basshorns) are primarily second and third, this is a pretty good indication of THD+N.

We measured amplitude response and distortion at 28.3v, 100 watts, 200 watts, 400 watts, 800 watts, and so on up to 1600 watts or the maximum allowed by the owner of the cabinet. The distance was 10 meters, so add 20dB to get the value at 1 meter. Each response chart shows SPL as a blue line and THD+N distortion as a violet line. To know the amount of distortion present, simply subtract the distortion from the SPL to read a decibel value, -35dB, for example.

Then to convert to a percentage, use the following conversion chart:

-60dB = 0.1%
-55dB = 0.2%
-50dB = 0.3%
-45dB = 0.5%
-40dB = 1%
-35dB = 2%
-30dB = 3%
-25dB = 5%
-20dB = 10%
-15dB = 15%
-10dB = 30%
-5dB = 55%

If the distortion level falls below the line shown in the noise floor measurement, then distortion is unknown. One can only know it is below the noise floor, approximately 65-70dB. Typical amplitude response ranged from 105dB to 120dB, so the average dynamic range was approximately 40dB. That means distortion below about 1% was too low to measure with this setup. To get more resolution, we could have moved the microphone closer but since we were primarily concerned with high power levels, 1% resolution was sufficient.


BassMaxx X2C Deuce [message #28301 is a reply to message #28299] Sun, 21 October 2007 13:21 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18677
Registered: January 2001
Illuminati (33rd Degree)
http://prosoundshootout.com/Photos/2007/Bassmaxx_Deuce.jpg
BassMaxx X2C Deuce basshorn sub

First, we measured impedance and found Zmin to be 3.35Ω. So 18.3v is required for 100 watts, 25.9v for 200 watts, 36.6v for 400 watts, 51.8v for 800 watts and 73.2v for 1600 watts.

http://prosoundshootout.com/Measurements/2007/BassMaxx_Impedance.jpg
Bassmaxx impedance

Next, we measured output at 28.3v. Since we measured 10 meters away, the values correspond to 2.83v/1M.

The blue line is SPL, and the violet line shows distortion. Since measurement was taken at 10 meters, add 20dB to find SPL at 1 meter. With 100 watts input, the 10 meter measurement works out the same as 1 watt input measured at a distance of 1 meter.

http://prosoundshootout.com/Measurements/2007/BassMaxx28v.jpg
Bassmaxx response at 10 meters with 28.3v input (2.83v/1M)

From this, we perform an inverse FFT to obtain impulse and step response:

http://prosoundshootout.com/Measurements/2007/Bassmaxx_Impulse.jpg
BassMaxx Impulse Response

http://prosoundshootout.com/Measurements/2007/Bassmaxx_Step.jpg
BassMaxx Step Response


Measurement at 100 watts:
http://prosoundshootout.com/Measurements/2007/BassMaxx100w.jpg
BassMaxx response at 10 meters with 18.3v (100w) input (1W/1M)


Measurement at 200 watts:
http://prosoundshootout.com/Measurements/2007/BassMaxx200w.jpg
BassMaxx response at 10 meters with 25.9v (200w) input


Measurement at 400 watts:
http://prosoundshootout.com/Measurements/2007/BassMaxx400w.jpg
BassMaxx response at 10 meters with 36.6v (400w) input


Measurement at 800 watts:
http://prosoundshootout.com/Measurements/2007/BassMaxx800w.jpg
BassMaxx response at 10 meters with 51.8v (800w) input


Measurement at 1600 watts:
http://prosoundshootout.com/Measurements/2007/BassMaxx1600w.jpg
BassMaxx response at 10 meters with 73.2v (1600w) input
Fitzmaurice Titan 48 [message #28302 is a reply to message #28299] Sun, 21 October 2007 13:31 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18677
Registered: January 2001
Illuminati (33rd Degree)
http://prosoundshootout.com/Photos/2007/Titan48.jpg
Fitzmaurice Titan 48 basshorn sub

First, we measured impedance and found Zmin to be 6.25Ω. So 25v is required for 100 watts, 35.4v for 200 watts, 50v for 400 watts and 70.7v for 800 watts.

http://prosoundshootout.com/Measurements/2007/Titan_Impedance.jpg
Titan 48 impedance

Next, we measured output at 28.3v. Since we measured 10 meters away, the values correspond to 2.83v/1M.

The blue line is SPL, and the violet line shows distortion. Since measurement was taken at 10 meters, add 20dB to find SPL at 1 meter. With 100 watts input, the 10 meter measurement works out the same as 1 watt input measured at a distance of 1 meter.

http://prosoundshootout.com/Measurements/2007/Titan28v.jpg
Titan 48 response at 10 meters with 28.3v input (2.83v/1M)

From this, we perform an inverse FFT to obtain impulse and step response:

http://prosoundshootout.com/Measurements/2007/Titan_Impulse.jpg
Titan 48 Impulse Response

http://prosoundshootout.com/Measurements/2007/Titan_Step.jpg
Titan 48 Step Response

Measurement at 100 watts:
http://prosoundshootout.com/Measurements/2007/Titan100w.jpg
Titan 48 response at 10 meters with 25v (100w) input (1W/1M)

Measurement at 200 watts:
http://prosoundshootout.com/Measurements/2007/Titan200w.jpg
Titan 48 response at 10 meters with 35.4v (200w) input

Measurement at 400 watts:
http://prosoundshootout.com/Measurements/2007/Titan400w.jpg
Titan 48 response at 10 meters with 50v (400w) input

Measurement at 800 watts:
http://prosoundshootout.com/Measurements/2007/Titan800w.jpg
Titan 48 response at 10 meters with 70.71v (800w) input
JTR Growler [message #28303 is a reply to message #28299] Sun, 21 October 2007 13:43 Go to previous messageGo to previous message
Wayne Parham is currently offline  Wayne Parham
Messages: 18677
Registered: January 2001
Illuminati (33rd Degree)
http://prosoundshootout.com/Photos/2007/Growler.jpg
JTR Growler basshorn sub

First, we measured impedance and found Zmin to be 5.5Ω. So 23.5v is required for 100 watts, 33.2v for 200 watts, 46.9v for 400 watts and 66.3v for 800 watts.

http://prosoundshootout.com/Measurements/2007/Growler_Impedance.jpg
Growler impedance

Next, we measured output at 28.3v. Since we measured 10 meters away, the values correspond to 2.83v/1M.

The blue line is SPL, and the violet line shows distortion. Since measurement was taken at 10 meters, add 20dB to find SPL at 1 meter. With 100 watts input, the 10 meter measurement works out the same as 1 watt input measured at a distance of 1 meter.

http://prosoundshootout.com/Measurements/2007/Growler28v.jpg
Growler response at 10 meters with 28.3v input (2.83v/1M)

From this, we perform an inverse FFT to obtain impulse and step response:

http://prosoundshootout.com/Measurements/2007/Growler_Impulse.jpg
Growler 48 Impulse Response[/img]

http://prosoundshootout.com/Measurements/2007/Growler_Step.jpg
Growler Step Response[/img]

Measurement at 100 watts:
http://prosoundshootout.com/Measurements/2007/Growler100w.jpg
Growler response at 10 meters with 23.5v (100w) input (1W/1M)

Measurement at 200 watts:
http://prosoundshootout.com/Measurements/2007/Growler200w.jpg
Growler response at 10 meters with 33.2v (200w) input

Measurement at 400 watts:
http://prosoundshootout.com/Measurements/2007/Growler400w.jpg
Growler response at 10 meters with 46.9v (400w) input

Measurement at 800 watts:
http://prosoundshootout.com/Measurements/2007/Growler800w.jpg
Growler response at 10 meters with 66.3v (800w) input
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