Hi, I d just like some comments/ideas on where to head for better sound in my churchs youth room.
This a medium sized room with a brick wall on the side behind the speakers, other three sides are drywall.
Our setup:
x2 Mackie SRM450 (v1 thank god)
x2 Mackie SRS1500
those are running from a Mackie VLZ board through a dbx 231 eq.
I just bought and fixed up a pair of JBL MR826's because we are trying to head in the passive direction. Powering with a Mackie m1400i. Yes we have too much Mackie.
Our plan now is to sell both the srm's, sr's and the mr's and build 3-ways from a PRV audio design this summer.
Can someone also point me to threads discussing active vs. passive?
This a medium sized room with a brick wall on the side behind the speakers, other three sides are drywall.
Our setup:
x2 Mackie SRM450 (v1 thank god)
x2 Mackie SRS1500
those are running from a Mackie VLZ board through a dbx 231 eq.
I just bought and fixed up a pair of JBL MR826's because we are trying to head in the passive direction. Powering with a Mackie m1400i. Yes we have too much Mackie.
Our plan now is to sell both the srm's, sr's and the mr's and build 3-ways from a PRV audio design this summer.
Can someone also point me to threads discussing active vs. passive?
DIY Audio Articles
IMHO, its better to keep active speakers, especially when you don't know who the sound engineer is. The good active speakers these days are essentially indestructable: they have every form of driver protection needed.
Systems with active crossovers can (and will) be tampered with.
What's the budget, and what would you like the outcome to be?
Chris
IMHO, its better to keep active speakers, especially when you don't know who the sound engineer is. The good active speakers these days are essentially indestructable: they have every form of driver protection needed.
Systems with active crossovers can (and will) be tampered with.
What's the budget, and what would you like the outcome to be?
Chris
You have a good point considering I won't know who's running it, but they will not have active crossovers. Too much expense unless I find a dbx one on CL for $50 or something crazy like that. And if five years down the road someone thinks it's all crap and redoes it to active because they don't bother learning, that's not my problem. I am trying to use my available resources while I'm still here.
Budget: I would hope after selling the two pairs, plus budget we would have around $800-$1000.
Outcome: I have a pretty good hifi setup at home. I don't want our PA speakers to rival that or anything, but I would like things to sound accurate, if that makes sense. A flat as possible frequency response and clarity in that crucial midrange, which is why we're leaning towards 3-ways.
... So you want to use a passive crossover on 3-way speakers, and use an external amplifier?
IMHO, you're seriously better off with what you have. Bear in mind that, when using external amps and no processing, you're leaving your drivers open to signals that can cause damage. Driving the amp hard into clipping or shoving some very low frequencies into the speakers will just kill the drivers. Active speakers protect against all of that, so I'd prioritise the survival of the setup over the next bit of detail.
You might be able to sell the lot and get a pair of QSC K12s. Maybe.
But the K12s won't have the low-end that the current system has. Better through the midrange, sure, but, for this application, I'd want the subs.
Chris
IMHO, you're seriously better off with what you have. Bear in mind that, when using external amps and no processing, you're leaving your drivers open to signals that can cause damage. Driving the amp hard into clipping or shoving some very low frequencies into the speakers will just kill the drivers. Active speakers protect against all of that, so I'd prioritise the survival of the setup over the next bit of detail.
You might be able to sell the lot and get a pair of QSC K12s. Maybe.
But the K12s won't have the low-end that the current system has. Better through the midrange, sure, but, for this application, I'd want the subs.
Chris
I tend to agree with Chris: looking at the mackie gear that is there, and notwithstanding personal tastes for or against Mackie, I suspect that it would be a serious challenge to:
(a) Achieve better perfromance
(b) Provid equal or better ease of use for the "customers"
(c) Deliver ruggedness and
(d) equal the SPL
Without investment over and above what you can get by selling the gear.
My experience is that active crossovers are essential for achieving high SPL, especially in larger spaces. The industry hasn't arrived at this position by accident.
(a) Achieve better perfromance
(b) Provid equal or better ease of use for the "customers"
(c) Deliver ruggedness and
(d) equal the SPL
Without investment over and above what you can get by selling the gear.
My experience is that active crossovers are essential for achieving high SPL, especially in larger spaces. The industry hasn't arrived at this position by accident.
I would suggest the best thing to invest in is some sound dampening for the brick wall behind the speakers. This allows standing waves in the room that will cause strange responses that are not the speakers fault. Wide short rooms are not good sounding anyway, by dampening out the reflections you can at least make it more accurate.
The best pair of speakers I've ever heard are the ones I own now, a pair of Peavey SP2-XT two way speakers. I don't have an opinion of the Mackie, they don't sell them here in stores, but proper treatment of the crossover can be done. bits of insulation, assymetric installation of the driver, reinforcement ribs, are all low cost bits of a speaker that can make for success or failure at accurate reproduction. The speaker enclosure itself can have standing waves and resonances internally, which mess up the response. Not to mention the bass treatment, reflex, ported, acoustic suspension, what? Several reasons I don't build speakers myself, the testing in an anechoic chamber to get it right is time consuming, requires expensive mikes, and is beyond my patience. My high school friend's diy four way speaker was rather horrid, IMHO. In my younger years I blew two tweeters in purchased multidriver speakers somehow with a dynakit tube amp, and the replacement drivers I could buy also made the speakers sound horrible. So details of drivers matter, also speaker protection is a good thing.
The fact that speakers are designed in an an-echoic room should be a big hint. Go to a charity resale shop, get some drapes, hang them along the brick wall. Behind the good looking drapes you can hang all sorts of echo damping stuff- actual purchased foam sound bats, carpet or even egg cartons glued on the brick. Some sort of softening treatment on one or more other walls could help sound accuracy, also. I use bookshelves and overstuffed furniture in my living/music room, which sounds really good IMHO. I use grand piano source for sound checks of speakers or room, since I have a good opinion of what they are supposed to sound like. The top octave is particularly hard to reproduce - Peter Nero Young and Warm & Wonderful has a top octave grand piano passage on a track I use for auditioning speakers and setups. This passage flushes out IM distortion very well, with many drivers making the piano sound as if it had vibrato. Pros use pink noise from a generator to set up a room, a calibrated microphone, and some tedious measurements. My method is a bit quicker. One problem with a group room, it has to sound good in more than one location - more measurements are required.
Good luck.
The best pair of speakers I've ever heard are the ones I own now, a pair of Peavey SP2-XT two way speakers. I don't have an opinion of the Mackie, they don't sell them here in stores, but proper treatment of the crossover can be done. bits of insulation, assymetric installation of the driver, reinforcement ribs, are all low cost bits of a speaker that can make for success or failure at accurate reproduction. The speaker enclosure itself can have standing waves and resonances internally, which mess up the response. Not to mention the bass treatment, reflex, ported, acoustic suspension, what? Several reasons I don't build speakers myself, the testing in an anechoic chamber to get it right is time consuming, requires expensive mikes, and is beyond my patience. My high school friend's diy four way speaker was rather horrid, IMHO. In my younger years I blew two tweeters in purchased multidriver speakers somehow with a dynakit tube amp, and the replacement drivers I could buy also made the speakers sound horrible. So details of drivers matter, also speaker protection is a good thing.
The fact that speakers are designed in an an-echoic room should be a big hint. Go to a charity resale shop, get some drapes, hang them along the brick wall. Behind the good looking drapes you can hang all sorts of echo damping stuff- actual purchased foam sound bats, carpet or even egg cartons glued on the brick. Some sort of softening treatment on one or more other walls could help sound accuracy, also. I use bookshelves and overstuffed furniture in my living/music room, which sounds really good IMHO. I use grand piano source for sound checks of speakers or room, since I have a good opinion of what they are supposed to sound like. The top octave is particularly hard to reproduce - Peter Nero Young and Warm & Wonderful has a top octave grand piano passage on a track I use for auditioning speakers and setups. This passage flushes out IM distortion very well, with many drivers making the piano sound as if it had vibrato. Pros use pink noise from a generator to set up a room, a calibrated microphone, and some tedious measurements. My method is a bit quicker. One problem with a group room, it has to sound good in more than one location - more measurements are required.
Good luck.
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Thank you all for the responses!
Cuppa Joe:
http://prvaudio.com/projectdesigns.html
They mention a 3-way design coming soon.
Googlyone:
You raise some good points. I think the overall message so far is that I need to get out and do a little fundraising.
Indianajo:
That's a work in progress, Wenger is in town and we're trying to get some good panels from them, otherwise that is the direction we will take.
I get your point about building our own, which is why we would do a design by a speaker manufacturer. Eventually we can probably get amps with safety features that will let us triamp them.
At one point, we did have a ton of couches that I'm sure absorbed sound pretty well. We had to destroy a good number of them, as they were becoming....questionable to sit on. I guess it's time to get some more!
I'll send a picture of the room in an hour or two.
Cuppa Joe:
http://prvaudio.com/projectdesigns.html
They mention a 3-way design coming soon.
Googlyone:
You raise some good points. I think the overall message so far is that I need to get out and do a little fundraising.
Indianajo:
That's a work in progress, Wenger is in town and we're trying to get some good panels from them, otherwise that is the direction we will take.
I get your point about building our own, which is why we would do a design by a speaker manufacturer. Eventually we can probably get amps with safety features that will let us triamp them.
At one point, we did have a ton of couches that I'm sure absorbed sound pretty well. We had to destroy a good number of them, as they were becoming....questionable to sit on. I guess it's time to get some more!
I'll send a picture of the room in an hour or two.
Instead of selling the SRM's, I am considering keeping them and loaning them out for a certain amount per hour. So that way we have them if needed and they keep generating money.
Cheapest thing you can do is get hold of a load of sound absorbing stuff. Rooms do terrible things to otherwise fairly nice speakers.
If/when you upgrade the speakers, the room treatment will benefit those, too.
With regards to loaning the speakers, be careful - make sure you get a deposit or something that'll ensure you still get your money, even if the speakers come back completely blown.
What's wrong with how the Mackies sound at the moment?
Chris
If/when you upgrade the speakers, the room treatment will benefit those, too.
With regards to loaning the speakers, be careful - make sure you get a deposit or something that'll ensure you still get your money, even if the speakers come back completely blown.
What's wrong with how the Mackies sound at the moment?
Chris
Yes, they will for sure sign some papers and have a deposit.
The Mackies just are cheap and old. They are not made out of wood (the subs are Baltic birch however) and the built in amps have a constant hiss and hum even with no connection. The midrange feels lacking even with eq. I just feel like there are a lot of better options.
Room treatments will happen soon.
The Mackies just are cheap and old. They are not made out of wood (the subs are Baltic birch however) and the built in amps have a constant hiss and hum even with no connection. The midrange feels lacking even with eq. I just feel like there are a lot of better options.
Room treatments will happen soon.
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There are a lot better options in powered speakers than the old SRM450 but you have to pay to get it. I also don't see you getting as full a sound from any 3-way speaker as you can get from a sub/sat system so you should retain that config if fullrange music is part of the program material, but if it isn't or it's only a small part of the program then maybe consider a system that is more midrange/vocal centric with multiple drivers covering that spectrum.. such as the those from JTR speakers.
JTR Speakers|Professional Audio Speakers
JTR Speakers|Professional Audio Speakers
Bar PA setups don't have to be quiet during the lesson or prayer, they play all the time.
Hum could probably be cabling or maybe old electrolytic caps, but hiss comes from the factory IMHO. My SP2-XT PA speakers came with a 1998 Peavey CS800s amp that is hiss/hum free (but trips the breaker, it probably needs power supply e-caps). The CS800s uses 4560 op amps. My Peavey PV-1.3k amp is from the bargain line, uses 4558 op amps, and will probably hiss idle when I get done putting effective protection circuits on it.(also left out at that price point). I exterminated the hiss in a 50x gain LP mixer by replacing 4558 op amps with lower noise 33078 op amps, and upgrading the power supply to eliminate oscillations from the faster OA's. the 33078's sounded the same as the 4560 op amps when I swapped some into the CS800s- so probably equivalent noise performance. Most low priced products like mackies would probably have the almost free 4558, since it doesn't require another $3 in ceramic caps to not oscillate.
You might be able to tinker with the Mackies to eliminate Hiss and hum, but opening up a powered speaker runs the risk of loosening a bit of fluff that was smoothing the frequency response out. Most everything is surface mount these days anyway, which takes $600 in tools to fool with effectively.
I kind of wondered what the difference between the Peavey plastic PR15 speaker and the wood SP2 speaker was: they ahve similar drivers but a different price point. Maybe hum and hiss levels are part of it, also effectiveness of the QA people in making sure every bit of insulation gets glued in the right place - even on third shift Saturday night.
I see the sub/sat point. I may try to contact that company because those look like some great speakers.
Wow! They use 4560 and 2068, some pretty decent op-amps. I think the subs use 5532.
All surface mount of course, so I don't think I'll bee opening anything up anytime soon.
An externally hosted image should be here but it was not working when we last tested it.
Wow! They use 4560 and 2068, some pretty decent op-amps. I think the subs use 5532.
All surface mount of course, so I don't think I'll bee opening anything up anytime soon.
Yes, 2068 and 4560 are low noise op amps. IMHO. NJM2068 is .56 microvolt noise with 300 ohm source. NJM4558 is 1.4 microv @ 1000 ohm source. TI 4560 is 1,2 microv @ <2kohm source.
Its hard to compare with all the difference source impedances, and 33078 is microv per sqareroot hz, which is totally different, but I've found 33078 and 4560 had less his than 4558. I never bought any 2068. My disco mixer hiss was annoying when I bought it for $15, is pretty tame now.
Slew rate is the spec that I think can cause op amps to oscillate, 4558 is low slew rate and doesn't need power supply ceramic caps nearby, nor ~33 pf around the feedback resistor, like 33078 needed. All of them are 5 to 6 v/microsec except 4558, which is 1.
At age 64 I can just barely see markings on leaded parts, those surface mount parts keep me out of certain projects like blown up DVM's . The $600 air desoldering station and the lamp with magnifying glass are barriers, too. I do amp repair/mods on a coffee table in my music room. Just this year I went into reading glasses to see things.
You might look at replacing the amp in powered speakers like the Mackies see this thread http://www.diyaudio.com/forums/pa-systems/263310-replaceing-amps-powered-pa-speakers.html
especially what JM Fahey said. I can't say which powered amp boards are good replacements and which are junk, though. Staying with powered speakers does keep people in a semi-public area from stealing your 10 ga speaker cables and selling them for the copper. We allow sinners in our church too, especially the youth program.
Its hard to compare with all the difference source impedances, and 33078 is microv per sqareroot hz, which is totally different, but I've found 33078 and 4560 had less his than 4558. I never bought any 2068. My disco mixer hiss was annoying when I bought it for $15, is pretty tame now.
Slew rate is the spec that I think can cause op amps to oscillate, 4558 is low slew rate and doesn't need power supply ceramic caps nearby, nor ~33 pf around the feedback resistor, like 33078 needed. All of them are 5 to 6 v/microsec except 4558, which is 1.
At age 64 I can just barely see markings on leaded parts, those surface mount parts keep me out of certain projects like blown up DVM's . The $600 air desoldering station and the lamp with magnifying glass are barriers, too. I do amp repair/mods on a coffee table in my music room. Just this year I went into reading glasses to see things.
You might look at replacing the amp in powered speakers like the Mackies see this thread http://www.diyaudio.com/forums/pa-systems/263310-replaceing-amps-powered-pa-speakers.html
especially what JM Fahey said. I can't say which powered amp boards are good replacements and which are junk, though. Staying with powered speakers does keep people in a semi-public area from stealing your 10 ga speaker cables and selling them for the copper. We allow sinners in our church too, especially the youth program.
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We had a former youth who was now a DJ come back, "fixed" a few things, and stole our wireless dmx boxes.
Thanks for that thread link, I'll look into that!
Oh and I suppose if I wanted to stop the hiss on our mixer I would have to replace all the de/coupling caps...then maybe I could fix the first two channels (absolutely dead in the water)
Not sure if I'm ready for that project.
476 capacitors, and that's just the 28 mic channels. Dang.
Not sure if I'm ready for that project.
An externally hosted image should be here but it was not working when we last tested it.
476 capacitors, and that's just the 28 mic channels. Dang.
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Coupler caps have not been a source of hiss in my experience. I bought some tantalum 4.7 uf that had popcorn noise from the store, but I 've come to suspect TV repair parts shops sold a lot of rejects in the bins out front of the counter. I hate electrolytic caps, but in light duty applications where no current flows, failure rate is more like 1% at 20 years instead of 80% in power supply applications where the heat pressurizes the cracked rubber seals. I put 71 ecaps in my H100 organ, but not the 110 sustain caps that just delay switch point of a transistor, and those systains work fine and consistently, if 2/3 the switch time of the 1987 sustain ecaps put in another similar organ.
47 uf you could actually measure them with ohms x 20k to see if any are leaking. The big part of repairing a mixer is getting the cover with all those knobs off, IMHO.
UGH are 1000 hour service life caps. If I'm going to replace something I like to install >3000 hour caps, and in 22 uf 50 v you can get 10000 hour caps, which i have been buying for my organ projects.
My 1998 Peavey Unity mixer only hisses when I turn all three gains all the way up for my dynamic mike with not much output. The condensor mike side, with low gain I'm hiss free. You can hear the hiss difference on the two channels on my Yellow Bird track on inbojat.tumblr.com
This was a band breaking up sale so this mixer has been touring for some years, and all the pots seem to work. The power transformer physically hums, but not electrically. If you can find one like it on craigslist or somewhere. I got 2 SP2-XT speakers, Peavey 15" 2 way wedge monitor speaker, CS800s 360 w/ch amp, mixer, 100' 16+4 channel snake, Peavey graphic equalizer, Digitech Quad 4 rack effect, 2 speaker stands, 19" road case for $1000. All but the mixer and speakers had little problems. The speakers were dirty, covered in tobacco dust and ash.
So anyway, if you have the gain jacked up on some mike, maybe buying a mike with a higher output could solve a hiss problem. This Shure KSM27 on the low hiss channel cost me $80, though they usually go $300 on craigslist. Seller had just moved to town, was not working yet. KSM27 is just a regular cardioid condensor mike for recording groups in a quiet room, not super cardioid dynamic mike like a SM58 for supre close vocals with major noise cancelation behind the mike.
47 uf you could actually measure them with ohms x 20k to see if any are leaking. The big part of repairing a mixer is getting the cover with all those knobs off, IMHO.
UGH are 1000 hour service life caps. If I'm going to replace something I like to install >3000 hour caps, and in 22 uf 50 v you can get 10000 hour caps, which i have been buying for my organ projects.
My 1998 Peavey Unity mixer only hisses when I turn all three gains all the way up for my dynamic mike with not much output. The condensor mike side, with low gain I'm hiss free. You can hear the hiss difference on the two channels on my Yellow Bird track on inbojat.tumblr.com
This was a band breaking up sale so this mixer has been touring for some years, and all the pots seem to work. The power transformer physically hums, but not electrically. If you can find one like it on craigslist or somewhere. I got 2 SP2-XT speakers, Peavey 15" 2 way wedge monitor speaker, CS800s 360 w/ch amp, mixer, 100' 16+4 channel snake, Peavey graphic equalizer, Digitech Quad 4 rack effect, 2 speaker stands, 19" road case for $1000. All but the mixer and speakers had little problems. The speakers were dirty, covered in tobacco dust and ash.
So anyway, if you have the gain jacked up on some mike, maybe buying a mike with a higher output could solve a hiss problem. This Shure KSM27 on the low hiss channel cost me $80, though they usually go $300 on craigslist. Seller had just moved to town, was not working yet. KSM27 is just a regular cardioid condensor mike for recording groups in a quiet room, not super cardioid dynamic mike like a SM58 for supre close vocals with major noise cancelation behind the mike.
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Good point about the service life, I would probably instead get Nichicon 105C audio caps. But I really doubt I'll do that.
Nice setup! The hiss is with every channel muted, all aux returns completely down, and the master at unity. So it ain't the mics, and we use SM58's and 57's. So I don't really know where it would be coming from.
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