Adding an amplifier for sub-woofer duty.
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- čas přidán 23. 08. 2024
- For smaller events, the QSC PLD 4.2 works great for sub-woofer duty... however, a more powerful amplifier (better suited for sub-woofers) is added to our small amplifier rack. The QSC PLD 4.2 (that was used for subs) is now placed back into monitor duty with the other PLD 4.2.
gotta get a permanent dolly board on that rack now!
I own 4 of the JBL SRX 718 subs, so I know bout having to bridge amps to properly power these speakers, The Crown 5000i you have running your sub gets the job down without having to bridge the amp, also all the built in features are a plus as well.
Adding or upgrading amplifiers in a rack always seems to be a surprise when it comes to lifting or moving it. I'm running exclusively class D amplifiers now, but despite that the amplifier rack still weighs north of 80lbs... Two four-channel amps, and three stereo amps cover 90% of my needs. I'm planning to change out the three stereo amplifiers for a pair of smaller rated 4-channel units so I can have up to 8 monitor channels, not that I need 8 monitors often.
Some of the cheaper class Ds tout all sorts of power ratings, but don't weigh anything; a good class D still has some heft to it... Not a much as a class A/B or Class H, but they're still substantial.
Most certainly. The MA-5000i has some weight (not much when moving it around by itself), but add that weight to a case, and now I am considering a caster-board for the case. The MA5000 is class D, however, the build quality of the amp case is rather robust (it is not a cheap metal housing). The build quality adds weight!
We've been very pleased with the PLD 4-channel amps; we have another two PLD 4.2 amps in our larger amp rack. These have helped a lot with keeping the weight down to something manageable. Thanks for your comment.
@@stageleftaudio I will be migrating the amplifiers to another case in due course. The case they're currently in isn't deep enough to accommodate any of the connectivity for the larger amps, so I have to re-patch each time...which is a little frustrating. While I do that change, I'll be moving to wheeled racks... I may also go to smaller racks too, so they're more manageable while being carried. I have to endure cobblestones into some of the locations I work, so portability is still high on the needs list.
Sounds like you are getting everything under control. I cannot imagine rolling anything (including a car) on cobblestones!
Danke !
Great video as usual.
wouldn't it be better to use the 1U free space either divided by the 3 amps or between sub and monitor amp for airspace-cooling in hot sunny days?
I know they are fan cooled but even though, it won't hurt.
I work in IT and we never place more than 2 units (switches etc) together as the metal parts are somehow a part of the cooling system and to keep them cooler and prolong the life of them.
Thanks for the comment. There's no need to add space between amplifiers that have forced-air cooling. However, older class A/B amplifiers (even with fans), some models needed the space to ensure proper cooling; the amps in the video are all class D. For servers in a data-center, I would imagine it would be a little different (a lot more cooling, less humidity) to ensure operation. I'm not sure how well a rack server would last outside in 80 deg. (F). A lot of amplifiers would have no problem!
Have you done any videos on your power situation? I'm running a smaller one man operation at the moment, but am going to be growing and am interested in seeing what your team is using for electrical power.
We don't have any videos related too specific to our electrical power needs. Many of the shows we do have different power requirements. As well, many sites we have provided sound at had power availability issues, which dictated what equipment we could use. However, Class D amplifiers (either stand-alone or as part of a powered speaker) have greatly reduced the amount of current we need to do shows. We can provide sound for about 300 people (2 x tops, 1 x sub, 4 x monitors) and have basic LED lighting, and have enough power for a 4 piece band to run their amps and keyboards... all on 1 x 15amp circuit.
If you are using Class H or Class A/B amplifiers, you will need several circuits as you begin to expand.
Here's an event we did with the FOH PA, monitors, and lighting on 1 x 15amp circuit. The mixing console (which does not require much power) was on a separate circuit.
czcams.com/video/_Unv3HmJO64/video.html
For electrical power, here's a video covering generators; it references some past events where we used generator power:
czcams.com/video/gm4tq_FzqmQ/video.html
Hope this helps.
I have a question regarding subwoofers. The little church that I work with had installed a subwoofer on the back end of the stage and it's not a very big stage but it's where the base amp and drum kit reside. I thought 'why do we have a subwoofer right next to the base amp?' So I moved the sub to a tiny room off the side of the stage. I wanted to get it far enough away. Generally speaking do you think this was a good choice on my part? Thanks!
Hope your install went well!
Placing a subwoofer in a room (assuming the sub is needed for a service) is a bit odd, but I do understand about space issues on stage. The subwoofer you are referencing, is this a FOH sub that is used for all the events? Or, is this a subwoofer used by an AUX channel for the drummer (or the bassist)?
@@stageleftaudio Thanks the install went well and I'm still ironing out the kinks, in my head! That's another topic. The sub is a rebuilt box, I believe the amp was replaced. It was donated by one of the church members and it's probably not a pro or semi pro level sub but after the new PreSonus install the guy helping tweaked the EQ on it and the sound is fairly good. It's used for everything and I at least know how to push or pull more or less of it from FOH.
For sure, there is always other things to take care of after an install...
Regarding the sub, placing it in a room usually works if bass frequencies are NOT a big part of the band/musical service. However, there is a few issues with locating a sub away from the other FOH speakers (assuming the mid/high tops). Some of these issues I mention below may not be that big of an issue; it's really up to what works for the band and the overall sound.
With the sub sitting in a room:
- The bass frequencies are not time-aligned with the tops: This can affect the overall sound quality of instruments that are in the bass frequencies (i.e. bass guitar, kick/floor drums, keys) that may have higher frequencies included. The "definition" of the audio quality of bass instruments is usually found in the high frequencies of an instrument (including harmonics). Basically, the "definition" of a bass frequency would be heard first (from the tops)... then followed by the lower frequency. There may only be a few milliseconds of difference, but it could be enough to affect the overall sound quality.
- Placing a sub speaker in a room will probably create "standing-waves" in the room. This is a physics issues with low frequency sound waves. Depending on the size of the room (width or length), a standing-wave (low frequency energy) will occur that matches the width and/or length of the room. These standing waves can be amplified outside the room due to the walls potentially vibrating, which could result in a preponderance of bass (depending on the frequency). The size of your church room (where the band plays and guests sit) can produce standing waves as well.
- Keeping speakers in a side room next to a stage can sometimes cause a stage-wash of sound from the speaker. This could impact how the band hears other instruments.
The best way to determine if there will be an issue is to try out the setup. It may work for your setup! There's many variables involved with speaker placement, room size, volume requirements, the number of people in the room during the service, etc... you can't really tell what will work until you try it.
A church I used to mix for would place their guitar cabinets (not bass) in a side closet with the door open. This was to reduce the stage volume due to the cabinets. I did not work well when mic'ing the cabinets; the mics would pick up the frequency resonance of the room with both guitars; this made bringing one guitar up (or down) in the mix almost impossible.
Very important here... The sound from the guitar cabinets would spill out of the closet and it sounded like someone in another room was playing guitars along with the band! It was very annoying, but that's how they wanted to keep it, so I worked with it.
Sorry for the extended response! I wanted to try cover the most common issues.
Hope this helps.
@@stageleftaudio Great info. Thank you! I will use different placements to see what sounds best. I'll report back!
Sounds good. Keep us up to date on what you decide!