How do you test the durability of a speaker cabinet? UNINTENTIONALLY, of course! Here's how ProActive Sound tested the Carvin LM15...
We did sound for Full Monty at a private event in Valley Center. The place is a mansion, built up to be a "corporate retreat" on about 40 acres. Nice place, great event. The owner's son ran the show and it was all very successful and well organized.
At the end of the gig we broke down, and started moving equipment to the top of the driveway, which area is sloped in 2 directions. I put down the LM15s next to each other on the grass. Was afraid to stand them upright because of the slope, so I laid them down in "monitor" position. As I walked away to pick up another load I heard a horrible THUMP. Then another THUMP. Then 2 THUMPs at almost the same time. When I realized what this was, I turned around and saw BOTH the LM15s rolling down a dirt hill that had just been planted. Of course I didn't freak out, there's no point in that. I ran over to rescue the tumbling speakers but had to catch up first because they were still tumbling. It was like slow motion, but they still kept going.
I tested the speakers the next day and everything worked fine. I had to take off the speaker grills to blow out all of the accumulated dirt first, they both picked up dirt that jammed into the grills and also you could hear dirt & little rocks that got into the port vents. You can still hear little bits of dirt to this day when you turn the cabinets over.
The LM15s still sound great, and I have used them many times over since this durability test.
By the way, we performed another durability test on July 4th, 2008. I play bass, and was asked to do a 4th of July party with a former band member Donn Boyd. I had played on and off several gigs with Donn and his brother Guy who is a former coworker. Guy currently plays in 3 bands in the San Diego Area:
- Sun King (tribute to The Cult)
- Lipstick n Leather
- Way Cool Jr.
Guy and Donn are both excellent guitarists/musicians and good people. Playing in bands with both of them (and their cousin Gary Hanson) has always been "entertaining"... these guys rip into each other 24/7 as if they're family ;-) We've played several family events as well and they have all made me feel like part of the clan.
OK, well after the 4th of July party, we loaded up the van with the PA equipment (BTW Donn has his own PA so that's not the reason he wanted me to play bass :-) Of course, the van was parked on an incline AGAIN. All the speakers & amps were loaded on the van, last thing was the long bag with mic/spkr stands. A couple of us pushed this in through the side door of the van, but I had not closed the back doors. Another tumble and THUMP! It was one LM15 and my bass amp head this time. Not just a gentle roll down a dirt hill either, this time they both fell out of the van onto pavement, much more shock than before. Everything checked out fine the next day, a tribute to the LM15 construction and Carvin R600's rack box.
Note that I'm not 100% happy with Carvin and the R600. I've had to bring this piece in for service previously. The output from one of the amp channels had dropped, and the line out is all noise. First time I brought it in the tech could not find anything wrong. They had it for over 3 weeks and I suspect they did not even look at it during that time. Second time they couldn't find a problem either but I insisted they take another look. I went into the repair area with the tech, and we hooked up a bass and then an MP3 player, and it sounded fine. I believe they cleaned it up this time without looking for the problem first. Maybe covering up the first time it was in and they did nothing, who knows... The line out is still useless. I plan to bring it in AGAIN but this time they're going to have to do the service for no cost. I already paid the service fee twice for the same problems. Carvin is very flexible and reasonable so I'm sure they will oblige. A future post will state the results.
Sunday, September 7, 2008
Sunday, August 17, 2008
Carvin LM15
I bought a pair of LM15s from Carvin and could not be happier with them... here's why:
At first, I went into the San Diego showroom to purchase LS1502 speakers. My first shot at doing a PA rental for the Full Monty Band was at the Coyote Bar & Grill in Carlsbad. Rich mentioned in our conversation regarding the band instruments and mic'ing requirements, that they typically use a sub plus a pair of 15" full range cabinets on stands. There is not much room for setup at the Coyote. It is an outdoor patio venue and the band sets up at one end of the patio.
At the time, my main speakers were the LS1801 subwoofers plus a pair of 1588s that were my original purchase for my band Shotgun. I had told Rich about the size of the speakers and he said we could make it work, of course, but in the end I decided to take Rich's advice on using speakers on stands. I had been considering whether to buy LS1502 or LM15 speakers for a few weeks already. Main point was to be able to use these speakers on stands for mains, or as monitors, so either series would work for this. Carvin had just recently introduced the LSx series, and put the LS series on sale to clear inventory. $219 each, great price for the perfect speakers for my needs!
Unfortunately when I arrived at the Coyote and opened the boxes, imagine my surprise when the speaker cabs I pulled out where rectangular boxes!!! What happened was they ran out of stock on LS1502 and substituted the LSx1502 without mentioning it to me. Well I used the LSx1502s for the night, and also for a gig (PA rental) the next day aboard the USS Midway for the reception for George Martin, who had just finished his Journey for 911 fundraiser walk across America the day before. Just to mention, the LSx1502 speakers sounded fantastic, and I would have kept them if they could have been turned on the ground as monitors.
Next day I went back into Carvin - I live nearby in Poway, CA. I explained that I wanted the LS1502 speakers because I needed to be able to use them as monitors. Derek went back to see what had happened. It turned out that they had run out of stock, as mentioned before. He offered to exchange the LSx1502 speakers for LM15s if I wanted to, for the same price. This sounded good to me because I had been considering these already, so I went ahead with the exange.
The Full Monty Band played a party on the next weekend. It was for a 25th anniversary, held outdoors at a newly finished resort / corporate retreat house in Valley Center. We used the LM15s with LS1801 subs for this gig and the sound was also great! We were all very happy with the sound...
...More coming soon...
At first, I went into the San Diego showroom to purchase LS1502 speakers. My first shot at doing a PA rental for the Full Monty Band was at the Coyote Bar & Grill in Carlsbad. Rich mentioned in our conversation regarding the band instruments and mic'ing requirements, that they typically use a sub plus a pair of 15" full range cabinets on stands. There is not much room for setup at the Coyote. It is an outdoor patio venue and the band sets up at one end of the patio.
At the time, my main speakers were the LS1801 subwoofers plus a pair of 1588s that were my original purchase for my band Shotgun. I had told Rich about the size of the speakers and he said we could make it work, of course, but in the end I decided to take Rich's advice on using speakers on stands. I had been considering whether to buy LS1502 or LM15 speakers for a few weeks already. Main point was to be able to use these speakers on stands for mains, or as monitors, so either series would work for this. Carvin had just recently introduced the LSx series, and put the LS series on sale to clear inventory. $219 each, great price for the perfect speakers for my needs!
Unfortunately when I arrived at the Coyote and opened the boxes, imagine my surprise when the speaker cabs I pulled out where rectangular boxes!!! What happened was they ran out of stock on LS1502 and substituted the LSx1502 without mentioning it to me. Well I used the LSx1502s for the night, and also for a gig (PA rental) the next day aboard the USS Midway for the reception for George Martin, who had just finished his Journey for 911 fundraiser walk across America the day before. Just to mention, the LSx1502 speakers sounded fantastic, and I would have kept them if they could have been turned on the ground as monitors.
Next day I went back into Carvin - I live nearby in Poway, CA. I explained that I wanted the LS1502 speakers because I needed to be able to use them as monitors. Derek went back to see what had happened. It turned out that they had run out of stock, as mentioned before. He offered to exchange the LSx1502 speakers for LM15s if I wanted to, for the same price. This sounded good to me because I had been considering these already, so I went ahead with the exange.
The Full Monty Band played a party on the next weekend. It was for a 25th anniversary, held outdoors at a newly finished resort / corporate retreat house in Valley Center. We used the LM15s with LS1801 subs for this gig and the sound was also great! We were all very happy with the sound...
...More coming soon...
Saturday, August 9, 2008
DIY DJ Setup SPL Measurements
We provided sound for a private back-yard party on 6/6. This event required the ability to comply with Poway municipal code for noise abatement. Limit of 50dB SPL at the adjacent property required. The SPL meter was set to the 60dB setting (which is the lowest range on the meter), with A-weighting, and slow response. The meter was held on the inside of the property close to the adjacent lot. Average SPL of 56dB registered on the meter with a reasonably loud sound level at the party area. The test was concluded at this point since the adjacent property is another 30 feet away from the meter location, and a row of Eucalyptus trees and other brush between serves to attenuate the sound more than the required 6dB as measured.
Guitar Center for Lighting
Looking for lighting equipment to cover a Friday night DJ setup. Went to the San Marcos Guitar Center last Saturday. I met Donnie there who was very helpful, but not too familiar with lighting. He said his area of expertise is in recording equipment. Donnie showed me what the GC had in stock, helped look up info on PAR lighting, explained the basics of DMX. They had an Elation hybrid controller for ~$330 in stock. This unit controlled DMX units as well as analog dimmers. Checked power ratings and pricing on PAR cans:
PAR38 (150W) $25; PAR56 (300W) $45 / $40 on-line; PAR64 (DMX RGB LED) $199
Info for PAR64 LED-based states they consume 30W, which is great for limiting power consumption of the overall system! Of course we want to be environmentally friendly, but also have the immediate need to limit our power consumption when using a generator. So apparently Donnie knew more than he realized about lighting, enough to be resourceful and to get me started on my learning.
One of the problems I found while visiting GC was that all the equipment in stock was made in China! I guess this was to be expected though, but I feel compelled to spend as much effort as possible to find controllers and lighting that is Made in USA. Second best would be to purchase equipment made overseas but is designed and tested in the USA. I sent requests to GC & Musicians Friend websites but have not received any replies yet after 2 days’ time.
I was able to find a DMX-based RGB LED PAR64 can on the web for $169 from TriNorthLighting, claimed to be better quality because the LEDs are made in USA… investigating further.
Also found good info on the DMX512 standard on wikipedia, and even some programming demo videos on YouTube :-)
PAR38 (150W) $25; PAR56 (300W) $45 / $40 on-line; PAR64 (DMX RGB LED) $199
Info for PAR64 LED-based states they consume 30W, which is great for limiting power consumption of the overall system! Of course we want to be environmentally friendly, but also have the immediate need to limit our power consumption when using a generator. So apparently Donnie knew more than he realized about lighting, enough to be resourceful and to get me started on my learning.
One of the problems I found while visiting GC was that all the equipment in stock was made in China! I guess this was to be expected though, but I feel compelled to spend as much effort as possible to find controllers and lighting that is Made in USA. Second best would be to purchase equipment made overseas but is designed and tested in the USA. I sent requests to GC & Musicians Friend websites but have not received any replies yet after 2 days’ time.
I was able to find a DMX-based RGB LED PAR64 can on the web for $169 from TriNorthLighting, claimed to be better quality because the LEDs are made in USA… investigating further.
Also found good info on the DMX512 standard on wikipedia, and even some programming demo videos on YouTube :-)
More on SPL measurements
First, there is very good information on A-weighting in sound measurements on wikipedia. http://en.wikipedia.org/wiki/A-weighting Most important is the shape of the curve. Compared to the C-weighted curve (the other most commonly used weighting curve), it is not nearly as flat and reflects more closely the human hearing characteristic. The D curve is also very interesting, which approximates the inverse of the equal loudness contour first determined in the 1930s. http://en.wikipedia.org/wiki/Equal-loudness_contour
By the way, please don't mess with Wikipedia... it's a great resource, even with the understanding that it may not be 100% accurate all the time. I've seen people playing around, one time a page was edited with "Sean is gay" for a few minutes, then was replaced with "You should not be reading this" and then the nonsense disappeared from the page. At least it didn't stick.
Next, I mentioned the inverse-squared law in relation to the measuremnts. This is well known within the wireless industry, and should be equally understood in acoustics. But what I did not realize was the effect of air resistance on the attenuation of sound. This is explained in my favorite reference book by Scott Hunter Stark "Live Sound Reinforcement". You can find this by doing a book search on Google, it actually contains images some pages (53-54 in this case). The attenuation of sound affects higher frequencies, so again the A-weighted curve is attenuated moreso than the C-weighted curve as you move away from the source.
In a previous entry, I mentioned the purchase of a hand-held SPL meter that will be used for a residential party. The party is to be held in Poway, CA. City of Poway municipal code Chapter 8.08 "NOISE ABATEMENT AND CONTROL" states (in various places; reformatted):
7. “Disturbing, excessive or offensive noise” means:
a. Any sound or noise which constitutes a nuisance involving discomfort or annoyance to persons of normal sensitivity residing in the area;
b. Any sound or noise conflicting with criteria standards or levels as set forth in this chapter for permissible noises;
c. Any sound or noise conflicting with criteria standards or levels established by Federal or State government which are applicable in the City.
20. “Sound level meter” means an instrument for the measurement of sound, including a microphone, an amplifier, an attenuator, networks at least for the standardized frequency weighting-A, and an indicating instrument having at least the standardized dynamic characteristic “fast,” as specified in American National Standard Specifications for Sound Level Meters S1. 4-1971 or the latest version thereof.
Zone or Land Use Designation / Applicable Limit One-Hour Average Sound Level (in decibels)
OS-RM, OS, OS/1du, RR-A, RR-B, RR-C, RS-2, RS-3, RS-4, RS-7, and Specific Plan, PRD and PC regulations with a density of 11 dwelling units or less per acre.
10:00 p.m. to 7:00 a.m. 40
7:00 a.m. to 10:00 p.m. 50
PF, RA, RC, MHP, and Specific Plan, PRD and PC regulations with a density of 11 or more dwelling units per acre.
7:00 a.m. to 7:00 p.m. 55
7:00 p.m. to 10:00 p.m. 50
10:00 p.m. to 7:00 a.m. 45
We will ProActively monitor and adhere to these limits and have a hard copy of the municipal code on-hand during the event. In addition, the placement and directivity of the speaker cabinets will make it almost trivial to avoid even coming close to these limits in this case... There is only one direction of concern (i.e. one offending neighbor) and this is NOT the direction that the speakers will be pointed anyway. In addition, this particular neighbor does not fit the description as set forth in the municipal code "persons of normal sensitivity residing in the area" and this fact has been documented over several years.
ProActive Sound can provide the same research, testing and preparation for YOUR event in YOUR municipality with sufficient lead time.
By the way, please don't mess with Wikipedia... it's a great resource, even with the understanding that it may not be 100% accurate all the time. I've seen people playing around, one time a page was edited with "Sean is gay" for a few minutes, then was replaced with "You should not be reading this" and then the nonsense disappeared from the page. At least it didn't stick.
Next, I mentioned the inverse-squared law in relation to the measuremnts. This is well known within the wireless industry, and should be equally understood in acoustics. But what I did not realize was the effect of air resistance on the attenuation of sound. This is explained in my favorite reference book by Scott Hunter Stark "Live Sound Reinforcement". You can find this by doing a book search on Google, it actually contains images some pages (53-54 in this case). The attenuation of sound affects higher frequencies, so again the A-weighted curve is attenuated moreso than the C-weighted curve as you move away from the source.
In a previous entry, I mentioned the purchase of a hand-held SPL meter that will be used for a residential party. The party is to be held in Poway, CA. City of Poway municipal code Chapter 8.08 "NOISE ABATEMENT AND CONTROL" states (in various places; reformatted):
7. “Disturbing, excessive or offensive noise” means:
a. Any sound or noise which constitutes a nuisance involving discomfort or annoyance to persons of normal sensitivity residing in the area;
b. Any sound or noise conflicting with criteria standards or levels as set forth in this chapter for permissible noises;
c. Any sound or noise conflicting with criteria standards or levels established by Federal or State government which are applicable in the City.
20. “Sound level meter” means an instrument for the measurement of sound, including a microphone, an amplifier, an attenuator, networks at least for the standardized frequency weighting-A, and an indicating instrument having at least the standardized dynamic characteristic “fast,” as specified in American National Standard Specifications for Sound Level Meters S1. 4-1971 or the latest version thereof.
Zone or Land Use Designation / Applicable Limit One-Hour Average Sound Level (in decibels)
OS-RM, OS, OS/1du, RR-A, RR-B, RR-C, RS-2, RS-3, RS-4, RS-7, and Specific Plan, PRD and PC regulations with a density of 11 dwelling units or less per acre.
10:00 p.m. to 7:00 a.m. 40
7:00 a.m. to 10:00 p.m. 50
PF, RA, RC, MHP, and Specific Plan, PRD and PC regulations with a density of 11 or more dwelling units per acre.
7:00 a.m. to 7:00 p.m. 55
7:00 p.m. to 10:00 p.m. 50
10:00 p.m. to 7:00 a.m. 45
We will ProActively monitor and adhere to these limits and have a hard copy of the municipal code on-hand during the event. In addition, the placement and directivity of the speaker cabinets will make it almost trivial to avoid even coming close to these limits in this case... There is only one direction of concern (i.e. one offending neighbor) and this is NOT the direction that the speakers will be pointed anyway. In addition, this particular neighbor does not fit the description as set forth in the municipal code "persons of normal sensitivity residing in the area" and this fact has been documented over several years.
ProActive Sound can provide the same research, testing and preparation for YOUR event in YOUR municipality with sufficient lead time.
Tuesday, August 5, 2008
SPL Testing
We ran a SPL check in the parking lot yesterday. Shotgun wants to play a gig at a campsite with the limit of 90dB SPL (A-weighted) at 50' from the stage. Since there was limited time, the test was simplified:
Acoustic level of the drums are the limiting factor for how "low" you can take the volume... you can't play any quieter than that!
One guitar was mic'd through the PA system. We piped an MP3 of a song that both the drummer and guitar player knew, and played along with it. A hand-held SPL meter was set to A-weighted measurement, and we measured out 50' from the PA speakers.
At 50', we were able to bring down the volume of the guitar and MP3 to 80~84dB average, with peaks of about 86~88dB. We agreed that the gig should go ahead, and the sound engineer will keep an eye on the meter during the performance.
Some other interesting measurements:
Cranked the MP3 player through the system to achieve 90dB average at 50'. Measured 100dB at around 25 feet and then 110dB at 5 feet. Each of the speaker drivers was able to exceed 120dB at a foot or so. It seemed the mid-high frequency drivers registers the highest levels. This is due to the nature of the A-weighted curve. Since human hearing tends to favor the mid-high frequency range just above 1kHz, the weighting of the meter is actually more sensitive to the smaller speakers. This doesn't mean that they are putting out more sound pressure, just that the meter registers a higher level for the same SPL with this setting.
The speakers used for this test were a pair of 1588's and LS1801's, powered by a DCM2500. which are all shown on our Equipment page.
Acoustic level of the drums are the limiting factor for how "low" you can take the volume... you can't play any quieter than that!
One guitar was mic'd through the PA system. We piped an MP3 of a song that both the drummer and guitar player knew, and played along with it. A hand-held SPL meter was set to A-weighted measurement, and we measured out 50' from the PA speakers.
At 50', we were able to bring down the volume of the guitar and MP3 to 80~84dB average, with peaks of about 86~88dB. We agreed that the gig should go ahead, and the sound engineer will keep an eye on the meter during the performance.
Some other interesting measurements:
Cranked the MP3 player through the system to achieve 90dB average at 50'. Measured 100dB at around 25 feet and then 110dB at 5 feet. Each of the speaker drivers was able to exceed 120dB at a foot or so. It seemed the mid-high frequency drivers registers the highest levels. This is due to the nature of the A-weighted curve. Since human hearing tends to favor the mid-high frequency range just above 1kHz, the weighting of the meter is actually more sensitive to the smaller speakers. This doesn't mean that they are putting out more sound pressure, just that the meter registers a higher level for the same SPL with this setting.
The speakers used for this test were a pair of 1588's and LS1801's, powered by a DCM2500. which are all shown on our Equipment page.
DIY DJ connection diagram
Connect multiple MP3 players (iPOD), laptop, CD player.
Plug in a microphone.
Connect up the amps and speakers.
Set up a looooooooooooong playlist!
Plug in a microphone.
Connect up the amps and speakers.
Set up a looooooooooooong playlist!
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