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Title: Suggestions for upgrade
Post by: Abel Duenas on September 03, 2011, 09:00:01 PM
Hi, Im new in this forum, Im the soundman at our church and we want to upgrade the sound system. We currently have 2 JBL MRX 515 on top of 2 PV SP118. We run the subs with a QSC 4050 and the JBL with 2 PV PV900 bridged one for each speaker. Now I was thinking about getting 2 SP3's on top of 2 PV SP218. Since the SP3 is a 3 way would it be an upgrade from the MRX, or would it be more like a side move? Our church is not very big the building not counting the altar is 60'Lx45'Wx18'H and we are about 160 members. Now if I could convince my pastor I would like to get QW 2's over QW 218's. Now my question is would that be overkill? I don't want louder sound I just want better sound and from what I read the QW 2's are made for long throw applications and if there's not too much of a difference between the QW and the SP for our application there's no point in spending more money. What do you guys think? Oh one more thing, we run the speakers through a VSX 26 processor. Any help would be greatly appreciated.
Title: Re: Suggestions for upgrade
Post by: Jonathan Johnson on September 04, 2011, 12:24:01 AM
First off, welcome to the forum. There are a lot of knowledgeable, experienced people in these forums and they are happy to help. If you lurk in any of the other pro audio forums on this board, some of the people there run shows for big-name acts.

But before anyone can help you, we need more information. Can you describe your worship style? What is it about the current system that doesn't meet your expectations? What are the problems you experience? Where in the sanctuary are the speakers placed relative to the stage/altar area and the audience?
Title: Re: Suggestions for upgrade
Post by: Abel Duenas on September 04, 2011, 01:17:11 AM
First off, welcome to the forum. There are a lot of knowledgeable, experienced people in these forums and they are happy to help. If you lurk in any of the other pro audio forums on this board, some of the people there run shows for big-name acts.

But before anyone can help you, we need more information. Can you describe your worship style? What is it about the current system that doesn't meet your expectations? What are the problems you experience? Where in the sanctuary are the speakers placed relative to the stage/altar area and the audience?

Thank you Jonathan for the welcoming to this forum :-) Well our worship style is very energetic, its kind of like rock and our music depends a lot on the kick drum and the bass guitar. Right now the kick drum is not strong enough even though I put a D6 on it. To me the SP 118's don't produce the kind of chest-pounding bass that I want, unless I'm doing something wrong which is likely. Now the MRX 515 are ok but the midrange tends to get a little bit lost. The speakers are placed in front of the altar one on each side about 2 feet away from the side walls and 15 feet away from the first row. We have 3 lines of pews and the speakers are pointing to the middle line about halfway. I hope I didn't confuse you with all of that.
Title: Re: Suggestions for upgrade
Post by: Brad Weber on September 04, 2011, 01:36:52 PM

Are your comments based on what you hear at the mix position or do they apply throughout the listener area?  How is the VSX26 set and what EQ are you applying on the mixer?  Have you tried anything like moving the speakers against the side walls rather than being 2' from them and/or running everything to one channel?  Those might indicate if interactions with the room or between speakers are involved.  Looking at the specifications for the products you noted I have a suspicion that you may get more potential improvement from optimizing what you already have than from simply changing the speaker with those noted.
Title: Re: Suggestions for upgrade
Post by: g'bye, Dick Rees on September 04, 2011, 01:44:41 PM
the kick drum is not strong enough even though I put a D6 on it.

Have you tried flipping the polarity on the kick mic to see what happens?  Are you certain your subs are not out of polarity with each other?
Title: Re: Suggestions for upgrade
Post by: Abel Duenas on September 04, 2011, 06:06:52 PM
Are your comments based on what you hear at the mix position or do they apply throughout the listener area?  How is the VSX26 set and what EQ are you applying on the mixer?  Have you tried anything like moving the speakers against the side walls rather than being 2' from them and/or running everything to one channel?  Those might indicate if interactions with the room or between speakers are involved.  Looking at the specifications for the products you noted I have a suspicion that you may get more potential improvement from optimizing what you already have than from simply changing the speaker with those noted.
Actually the mix position is opposite of the altar on the second floor, where I'm the kick drum sounds good and strong but once I go down to the sanctuary I can hardly hear it though I feel the kick when I touch the pews. We just moved the speakers closer to the walls and its an improvement but still the kick its not strong enough. I checked the polarity of the subs with a battery and they're ok. Now the church itself its an old church that was built around 1950 so I guess it was never designed to accomodate the kind of music that we play, but right now we don't have the budget to put some sound dampening material on the walls. The VSX's crossover is set L-R 24 @ 34 Hz on the subs and L-R 24 @ 100Hz on the MRX. The EQ is almost flat with a slight spike on 80Hz and a -3dB on 600-1500Hz. Now when I EQ'd the room with the AutoEQ on the VSX it gives a flat response from 200Hz-16Khz but it almost kills everything from 40 to 120 Hz. On the EQ I have the subs on a HPF_12 @ 35Hz and the mains on a HPF_12 @ 100Hz Both subs and mains have a Q of 0.707
Title: Re: Suggestions for upgrade
Post by: Brad Weber on September 05, 2011, 06:15:09 AM
The VSX's crossover is set L-R 24 @ 34 Hz on the subs and L-R 24 @ 100Hz on the MRX. The EQ is almost flat with a slight spike on 80Hz and a -3dB on 600-1500Hz. Now when I EQ'd the room with the AutoEQ on the VSX it gives a flat response from 200Hz-16Khz but it almost kills everything from 40 to 120 Hz. On the EQ I have the subs on a HPF_12 @ 35Hz and the mains on a HPF_12 @ 100Hz Both subs and mains have a Q of 0.707
I believe that with the VSX 26 a crossover is a set of bandpass filters with one filter for each related output, thus you should have a high pass setting and a low pass setting for both the subs and the mains.  You also would typically not need an additional high pass filter in the output equalization at the same frequency as the crossover high pass.
Title: Re: Suggestions for upgrade
Post by: Stu McDoniel on September 06, 2011, 10:47:00 AM
Hi, Im new in this forum, Im the soundman at our church and we want to upgrade the sound system. We currently have 2 JBL MRX 515 on top of 2 PV SP118. We run the subs with a QSC 4050 and the JBL with 2 PV PV900 bridged one for each speaker. Now I was thinking about getting 2 SP3's on top of 2 PV SP218. Since the SP3 is a 3 way would it be an upgrade from the MRX, or would it be more like a side move? Our church is not very big the building not counting the altar is 60'Lx45'Wx18'H and we are about 160 members. Now if I could convince my pastor I would like to get QW 2's over QW 218's. Now my question is would that be overkill? I don't want louder sound I just want better sound and from what I read the QW 2's are made for long throw applications and if there's not too much of a difference between the QW and the SP for our application there's no point in spending more money. What do you guys think? Oh one more thing, we run the speakers through a VSX 26 processor. Any help would be greatly appreciated.
I would change things around...first off I would run the Peavey bridged amps one each on the subs.  I would run the QSC on the JBL tops and get two more
identical tops and put them further down in the room facing down into the audience about 30ft on the sides of the room.  Keep in mind that when you bridge an amp
and have long cable runs you are drastically affecting damping.  There are other reasons NOT to bridge an amp and run high power.  If you are going to bridge then
put the bridged amps on the subs.  You can run the two JBLs you have up front
and the same JBLs on the sides further back in the room on the QSC with no
problems.   Move the subs together one one side of the stage or the other or better
yet if you can run them together center stage.  You will have MUCH better bass
response and even response in the room by having both subs together in ONE spot
4 JBLS /two up front /two on the side walls angled down into the room about 30ft back running on the QSC.  2 Peavey subs put in one spot coupled together configured as mono subs each running on a Peavey 900 amp bridged.
Things will change in that room big time if you do this
 
Title: Re: Suggestions for upgrade
Post by: Abel Duenas on September 06, 2011, 08:19:45 PM
I would change things around...first off I would run the Peavey bridged amps one each on the subs.  I would run the QSC on the JBL tops and get two more
identical tops and put them further down in the room facing down into the audience about 30ft on the sides of the room.  Keep in mind that when you bridge an amp
and have long cable runs you are drastically affecting damping.  There are other reasons NOT to bridge an amp and run high power.  If you are going to bridge then
put the bridged amps on the subs.  You can run the two JBLs you have up front
and the same JBLs on the sides further back in the room on the QSC with no
problems.   Move the subs together one one side of the stage or the other or better
yet if you can run them together center stage.  You will have MUCH better bass
response and even response in the room by having both subs together in ONE spot
4 JBLS /two up front /two on the side walls angled down into the room about 30ft back running on the QSC.  2 Peavey subs put in one spot coupled together configured as mono subs each running on a Peavey 900 amp bridged.
Things will change in that room big time if you do this
@Brad, so basically the filters that I have set on the outputs are redundant?
@Stu, that's a good idea having 2 more JBL's but will the 2 SP118's be enough having now a 2:1 ratio? I thought about coupling the subs centerstage like you said but wouldn't it be too loud for my pastor since they'd be right in front of the pulpit? Now if I bridge the PV amps would they be enugh since they're 600RMS which is equal to the RMS rating on the SP118's?
Title: Re: Suggestions for upgrade
Post by: Brad Weber on September 06, 2011, 10:12:06 PM
@Brad, so basically the filters that I have set on the outputs are redundant?
It would be unusual to need, for example, a crossover with a band that has a 24dB/octave high pass filter at 100Hz and then also need also a second 12dB/octave high pass filter at that same frequency.  What is also potentially relevant is what the low pass filter settings are for the subwoofer band of the crossover.
Title: Re: Suggestions for upgrade
Post by: Brad Weber on September 06, 2011, 10:48:34 PM
I would change things around...first off I would run the Peavey bridged amps one each on the subs.
Keep in mind that when you bridge an amp
and have long cable runs you are drastically affecting damping.  There are other reasons NOT to bridge an amp and run high power.  If you are going to bridge then
put the bridged amps on the subs.
Is this being suggested in order to support the two extra mains you suggested, which would apparently be in parallel with the currant mains and thus present a nominal 4 Ohm rather than 8 Ohm total impedance?  Otherwise it would seem to result in using in less power from a less capable amp for the subs when the primary issue is apparently not enough bass and kick drum.  Since you have the same load impedance and the same cabling whether the amp is in stereo or bridge mode, being bridge mode may have a negligible effect on the damping factor.

I would run the QSC on the JBL tops and get two more
identical tops and put them further down in the room facing down into the audience about 30ft on the sides of the room.
You can run the two JBLs you have up front
and the same JBLs on the sides further back in the room on the QSC with no
problems.
This might make sense in a long, narrow room with appropriate processing applied to the additional speakers but this room is apparently 60' deep and 45' wide and you would have no delay, separate level control, etc. for the second set of speakers.  Coverage was not noted to be a problem and this would seem to provide minimal, if any, potential improvement in coverage or levels for the kick drum and bass while adding significant additional combfiltering and timing issues over a broad frequency range.  In this application I just don't see the potential advantages offsetting the potential disadvantages.

Move the subs together one one side of the stage or the other or better
yet if you can run them together center stage.  You will have MUCH better bass
response and even response in the room by having both subs together in ONE spot.
Agreed, clustering the subs may help.  One reason I suggested trying the system run mono with just one set of speakers was to check on 'power alley' type issues that may be occurring being the split subs.
Title: Re: Suggestions for upgrade
Post by: Abel Duenas on September 07, 2011, 11:11:21 PM
Is this being suggested in order to support the two extra mains you suggested, which would apparently be in parallel with the currant mains and thus present a nominal 4 Ohm rather than 8 Ohm total impedance?  Otherwise it would seem to result in using in less power from a less capable amp for the subs when the primary issue is apparently not enough bass and kick drum.  Since you have the same load impedance and the same cabling whether the amp is in stereo or bridge mode, being bridge mode may have a negligible effect on the damping factor.
This might make sense in a long, narrow room with appropriate processing applied to the additional speakers but this room is apparently 60' deep and 45' wide and you would have no delay, separate level control, etc. for the second set of speakers.  Coverage was not noted to be a problem and this would seem to provide minimal, if any, potential improvement in coverage or levels for the kick drum and bass while adding significant additional combfiltering and timing issues over a broad frequency range.  In this application I just don't see the potential advantages offsetting the potential disadvantages.
Agreed, clustering the subs may help.  One reason I suggested trying the system run mono with just one set of speakers was to check on 'power alley' type issues that may be occurring being the split subs.
Coverage and intelligebility have never been a problem because although the room doesn't have the best accoustics, the congregation is able to hear the music and the sermon perfectly. Now I do think there's a power alley because about a month ago I burned a subwoofer so just one was working and to me it seemed that the bass was better defined and had a little bit more kick to it. Could it be possible that although the subs are in phase they are canceling each other out due to the accoustics or resonance in the room? Im going to try and put the subs in a center cluster this weekend and see how it goes. Now since it seems that I have the VSX settings wrong if it's not too much to ask what settings would you use with the set up that we have? Any help would be tremendously appreciated :-)
Title: Re: Suggestions for upgrade
Post by: Stu McDoniel on September 08, 2011, 11:09:25 AM
Is this being suggested in order to support the two extra mains you suggested, which would apparently be in parallel with the currant mains and thus present a nominal 4 Ohm rather than 8 Ohm total impedance?  Otherwise it would seem to result in using in less power from a less capable amp for the subs when the primary issue is apparently not enough bass and kick drum.  Since you have the same load impedance and the same cabling whether the amp is in stereo or bridge mode, being bridge mode may have a negligible effect on the damping factor.
This might make sense in a long, narrow room with appropriate processing applied to the additional speakers but this room is apparently 60' deep and 45' wide and you would have no delay, separate level control, etc. for the second set of speakers.  Coverage was not noted to be a problem and this would seem to provide minimal, if any, potential improvement in coverage or levels for the kick drum and bass while adding significant additional combfiltering and timing issues over a broad frequency range.  In this application I just don't see the potential advantages offsetting the potential disadvantages.
Agreed, clustering the subs may help.  One reason I suggested trying the system run mono with just one set of speakers was to check on 'power alley' type issues that may be occurring being the split subs.
I assumed the original OP would have enough knowledge to apply delay
to the extra cabs placed towards the back of the room and thus did not feel
the need to go into great detail.  Yes long cable runs affect damping factor
in a big way on bridged amps.   Why not add the two extra JBL loudspeakers
midway back in the room with proper delay and xover the subs down lower?
Im thinking that letting the 15" 2ways handle from 80hz up will give the system
more punch? Put the 18" cabs in one spot in the room to handle 80hz and down.
Having four JBLs distributed in the room will also allow the system to cover
the room much better and not be driven so hard.   It makes more sense to have more loudspeakers covering the space and "turn it down"...especially in a church!
This is what I would do with the system and everyone has their own opinion of course. 
Title: Re: Suggestions for upgrade
Post by: Jonathan Johnson on September 08, 2011, 03:12:30 PM
Coverage and intelligebility have never been a problem because although the room doesn't have the best accoustics, the congregation is able to hear the music and the sermon perfectly. Now I do think there's a power alley because about a month ago I burned a subwoofer so just one was working and to me it seemed that the bass was better defined and had a little bit more kick to it. Could it be possible that although the subs are in phase they are canceling each other out due to the accoustics or resonance in the room? Im going to try and put the subs in a center cluster this weekend and see how it goes. Now since it seems that I have the VSX settings wrong if it's not too much to ask what settings would you use with the set up that we have? Any help would be tremendously appreciated :-)

This is only anecdotal evidence since I can't explain the physics behind it.

A buddy discovered that when he stacked subs, he got better results in odd numbers. So one on top of another (two subs) did not provide as much "kick" as a single sub, and three subs in a stack was even better. He explained to me the physics behind it (he's an audiophile, but he IS also an engineer so he knows when to call BS) but I just don't remember.
Title: Re: Suggestions for upgrade
Post by: Taylor Phillips on September 08, 2011, 10:00:41 PM
Now I do think there's a power alley because about a month ago I burned a subwoofer so just one was working and to me it seemed that the bass was better defined and had a little bit more kick to it. Could it be possible that although the subs are in phase they are canceling each other out due to the accoustics or resonance in the room?
I think that's definitely possible - especially if you got better sound with only one sub working.  Play some recorded music through the system with only one sub on, then play the same thing with both subs and see how different the low end sounds. 

Also, if they subs would just be too in the way clustered together in front of the pulpit, you could try just putting them closer together i.e. one just to each side of the pulpit stairs.  It may not be as effective as clustering them, but it should help with the low end phase cancellation and power alley.  Something else I thought of would be to cluster them together just to one side. 
Title: Re: Suggestions for upgrade
Post by: Brad Weber on September 09, 2011, 01:30:28 AM
This is only anecdotal evidence since I can't explain the physics behind it.

A buddy discovered that when he stacked subs, he got better results in odd numbers. So one on top of another (two subs) did not provide as much "kick" as a single sub, and three subs in a stack was even better. He explained to me the physics behind it (he's an audiophile, but he IS also an engineer so he knows when to call BS) but I just don't remember.

I've known and worked with many Engineers who are very smart people but whose technical expertise did not include audio or acoustics.  I guess it is possible to get such results but the scenarios I envision would depend on the effects of the physical spacing of one sub to another and the spacing of the subs relative to the surrounding surfaces, in other words the results would be a factor of aspects other than the number of subs being odd or even.
Title: Re: Suggestions for upgrade
Post by: Jonathan Johnson on September 09, 2011, 01:44:24 AM
This is only anecdotal evidence since I can't explain the physics behind it.

A buddy discovered that when he stacked subs, he got better results in odd numbers. So one on top of another (two subs) did not provide as much "kick" as a single sub, and three subs in a stack was even better. He explained to me the physics behind it (he's an audiophile, but he IS also an engineer so he knows when to call BS) but I just don't remember.
I've known and worked with many Engineers who are very smart people but whose technical expertise did not include audio or acoustics.  I guess it is possible to get such results but the scenarios I envision would depend on the effects of the physical spacing of one sub to another and the spacing of the subs relative to the surrounding surfaces, in other words the results would be a factor of aspects other than the number of subs being odd or even.
I'm sure there are many variables that come into play. I should stress that my friend's experience was with a particular sub design in a particular environment, and had specifically to do with stacking the subs. Nevertheless it may be worth investigating.