Adding sub one sub: 15" vs. 18"

petty1818

Member
Messages
4,362
I am kind of on a mission right now to complete my PA rig. I started a thread last week about potentially switching from QSC to EV speakers but I decided to stick with the K12's I have and the K10 for my monitor. I have just always wanted to add a sub but I find it difficult to get a real answer on what I need as most of the forums that discuss subs are dedicated to DJ's who think that you need two massive subs to pump out the bass. Having talked to a few music stores and musicians, it sounds as though one sub is enough for me and two would be overkill.

Here's my set up. I have two bands currently; one is an acoustic/celtic group, which includes acoustic guitars, bass, electronic bass drum, fiddle and mandolin and four vocals. Typically the set up will be myself on either an acoustic or mandolin (depends on the song), another member on acoustic, a bass player who also adds bass drum for certain songs and a fiddle. We all sing four part harmony and we strum aggressively so lots of energy. Typically we play medium to large pubs (200-300 people) but we also do outdoor shows once in a while. Everything is run through the mains, including the bass and kick drum. The bass player has an amp that provides 80% of the volume, we just patch a bit of bass through the PA.

My other band is your typical rock group. Two electric guitars, bass and drums. For that group we generally play the same venues but like to mic the amps and feed the bass into the PA. Again, the amps provide most of the volume, it's just a bit more through the PA. I don't mic a kick drum since it's just two K12's but would like to on occasion.

With all that said, I would like to add a sub. I honestly think that I only need one sub. The QSC KW181 is the obvious choice but it's fairly heavy and I am not sure if it's overkill? I have looked at some of the EV subs, especially the EKX 15 powered sub but I always read that a single 15" sub is not enough. Again, this is from DJ's. It's hard to know what's best, especially for the acoustic group. I just know that with the K12's, I will have to switch them to ext sub mode so I want a sub that will fill in that bottom end and be loud enough so that my sound out front isn't lacking.
 

RCM78

Member
Messages
6,640
200-300 people with occasional outside gigs? I think you need two 18" subs and let the subs carry the bass load. The KW181's will work great.
 

petty1818

Member
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4,362
200-300 people with occasional outside gigs? I think you need two 18" subs and let the subs carry the bass load. The KW181's will work great.

Thanks! I just feel like two KW181's would be overkill. When I say outside gigs, I generally mean where we might be playing to 200-300 people sitting out front of the stage. The sound doesn't need to carry a far distance or anything.
 

Rex Anderson

Member
Messages
5,524
Good tight, punchy, clean, extended low end is hard to achieve indoors, let alone outdoors where there are no walls to reinforce the cabinet/drivers, just free space. This is one case where less isn't more.

Start with one and add another if you need it.
 
Last edited:

petty1818

Member
Messages
4,362
Interesting, I honestly thought one, especially the KW181 would be enough. Question, if two K12's produce enough sound for what we are doing now, why would one sub not give enough bottom end? Is it just because one Kw181 wouldn't have enough wattage to compete with both speakers? I find PA systems to be frustrating. I was reading one forum where a DJ showed his rig of 4 KW181's and what looked like 8 speaker tops and he said that's good for 200-300 people venues. Maybe I am crazy but that seems like overkill by a wide margin.
 

Rex Anderson

Member
Messages
5,524
Everything depends on the venue, the SPL and low frequency extension you are trying to produce. A good system designer can predict what you need to meet your goals. If you don't have access to a pro to do that, you keep buying more stuff until you get it right.

It's not about a sub "competing" with the mains. It's about integrating subs with the mains to achieve low frequency extension (flatter and lower frequency response) and SPL.

Having enough (and good enough) subs can be a costly venture depending on the venue, low frequency extension and SPL you are trying to achieve.

Generating bass requires lots of watts and speakers (again, depending on the venue). Small club, no problem. Bigger venue or outdoors, get out your checkbook.
 

335guy

Member
Messages
5,239
I agree with many of the posts, especially those that say need is dependent on venue size/type. OP, you may get along fine with a single 18" sub in some or most places. And as Rex pointed out, outside is another matter and where most likely, a single sub would not suffice. And as Rex said, you could get one and see how it goes. Then add or rent another when and if needed.

That said, before you run out and start buying gear, consider what is available. Just because you use QSC speakers now doesn't mean your sub must be a QSC sub. I'm not knocking the KW181. It is a fine sounding unit. However, I would seriously consider the JBL PRX718XLF. Why? It weighs much less, costs much less than the EV ETX-18SP or QSC KW181 and it has outstanding performance. The reason it costs so much less is because it is being phased out by newer JBL models and retailers are simply heavily discounting this speaker.

I'm not a JBL fanboy, but this speaker when new, was the competitor to the QSC KW181, and many believe the JBL beats the QSC in performance. It's specs are certainly impressive. If I were in the market to buy a new sub, it's the sub I most likely would purchase.

http://www.musiciansfriend.com/pro-...requency-subwoofer?pfm=item_page.rr1?pfm=ac-a
 

RCM78

Member
Messages
6,640
I agree with many of the posts, especially those that say need is dependent on venue size/type. OP, you may get along fine with a single 18" sub in some or most places. And as Rex pointed out, outside is another matter and where most likely, a single sub would not suffice. And as Rex said, you could get one and see how it goes. Then add or rent another when and if needed.

That said, before you run out and start buying gear, consider what is available. Just because you use QSC speakers now doesn't mean your sub must be a QSC sub. I'm not knocking the KW181. It is a fine sounding unit. However, I would seriously consider the JBL PRX718XLF. Why? It weighs much less, costs much less than the EV ETX-18SP or QSC KW181 and it has outstanding performance. The reason it costs so much less is because it is being phased out by newer JBL models and retailers are simply heavily discounting this speaker.

I'm not a JBL fanboy, but this speaker when new, was the competitor to the QSC KW181, and many believe the JBL beats the QSC in performance. It's specs are certainly impressive. If I were in the market to buy a new sub, it's the sub I most likely would purchase.

http://www.musiciansfriend.com/pro-...requency-subwoofer?pfm=item_page.rr1?pfm=ac-a
I have two 718XLF's and they work great for medium sized rooms with up to 400 people in them. With more and more outside gigs coming up this summer I'm thinking about adding one or two SRX828SP subs.
 

petty1818

Member
Messages
4,362
I agree with many of the posts, especially those that say need is dependent on venue size/type. OP, you may get along fine with a single 18" sub in some or most places. And as Rex pointed out, outside is another matter and where most likely, a single sub would not suffice. And as Rex said, you could get one and see how it goes. Then add or rent another when and if needed.

That said, before you run out and start buying gear, consider what is available. Just because you use QSC speakers now doesn't mean your sub must be a QSC sub. I'm not knocking the KW181. It is a fine sounding unit. However, I would seriously consider the JBL PRX718XLF. Why? It weighs much less, costs much less than the EV ETX-18SP or QSC KW181 and it has outstanding performance. The reason it costs so much less is because it is being phased out by newer JBL models and retailers are simply heavily discounting this speaker.

I'm not a JBL fanboy, but this speaker when new, was the competitor to the QSC KW181, and many believe the JBL beats the QSC in performance. It's specs are certainly impressive. If I were in the market to buy a new sub, it's the sub I most likely would purchase.

http://www.musiciansfriend.com/pro-...requency-subwoofer?pfm=item_page.rr1?pfm=ac-a

That's very true. I was actually going to upgrade my K12's but nothing else really made much sense, unless I wanted to go to the next level price wise. I am totally open to different subs. Here in Canada, we have Yorkville which is an amazing company. Downside is that their powered subs are insanely heavy. I believe their 18" powered sub is over 120lbs. I personally haven't heard great things about current JBL speakers but let me check it out. QSC does have a lot of hype behind it right now so a lot of times even the used prices are terrible. I am always open to more options. I think I will just have to get a sub and try it out. I think me mentioning 200-300 people venues and outside didn't help. The venues that fit that many are more so regular pubs/bars that are not that large, they just carry that many people.
 

335guy

Member
Messages
5,239
The Yorkville LS800P looks like the best sub but I don't know if I can handle 130lbs. That's excessive.

Ah yes, the LS801P. A member here, Floyd Eye, uses them. It is a monster sub and one can nearly take the place of two lessor subs. He claims moving them is easy, due to the wheels on them. Of course, if you have to lift them, then the weight is an issue. But if you can roll them into whatever vehicle you're using for transport via ramps, then the weight is much less of a consideration.
 

petty1818

Member
Messages
4,362
Ah yes, the LS801P. A member here, Floyd Eye, uses them. It is a monster sub and one can nearly take the place of two lessor subs. He claims moving them is easy, due to the wheels on them. Of course, if you have to lift them, then the weight is an issue. But if you can roll them into whatever vehicle you're using for transport via ramps, then the weight is much less of a consideration.

Did some research on the JBL sub and saw nothing but terrible reviews. The music store reviews are good but in forums people seem to hate them. I think the KW181 would be the best choice. I have a buddy who is a DJ and also had a band. They do weddings in large outdoor tents and large halls. He uses two K12's (sometimes 4) and one KW181. He has a second but said he hardly needs it. I really think one will be fine but I will have to give it a try. Just have to find a good deal on one.
 

sants

Member
Messages
2,690
Definitely go with an 18 and since you already have qsc I'd get the kw181. I use one for smaller shows and two for larger. The other brands are great but I'd stick with qsc since you already have one foot in the door. A 6 year warranty is always nice.

You may think an 18 is overkill until you need a little more punch. I'd rather go bigger than push a smaller sub to it's limits, though you are talking a few more decibels at most. The kw181 is not that big of a sub compared to many 15's on the market.

I'd rather have a twin reverb with tons of headroom than hope my Princeton reverb is up to task.

With a PA system, overkill usually means better unless you start stacking tons of speakers together to look impressive.
 

stevel

Member
Messages
15,780
Most bands don't even need a sub at all in most small-ish indoor venues. I would say the exceptions are if offloading the tops is really important, or if the band does in fact really have low frequency content that would benefit from having a sub to extend the frequency ranged down - low synth basses, DJ bass, metal kick, and 7 string low thump.

I'd say, given everything goes through the PA in the celtic group, the electronic drum could definitely benefit from going through the sub. If the bass is carrying that much volume on stage, maybe they shouldn't be.

Remember, low frequencies are far less directional and "spread" and "reflect" and "transmit through" things, so low frequencies can overwhelm quickly (which is why a band with bass amps on stage and the bass running through the sub is very often extreme overkill and mud - unless it's a heavy dance or funk band or something.

For the other band - well, again, unless it's metal and you need thunderous kicks...you don't really need them horribly. But definitely spreading your signal over more drivers certainly gives you more control over the frequencies. I hate going to see "rock" bands with kicks that sound like Metallica all night and omnipresent bass that just sounds like "whaaaaaaa" all night with no distinction on notes. Part of this is just people not knowing how to run their subs, but another part of it is people think they need it to sound like this, but realistically they don't. I wouldn't want to hear your celtic group and hear metallica kick or DJ thump from the electronic drum. I'd want it to be "appropriate" to the mix.

That said, for outdoor - the bass goes away. Those huge wavelengths can travel unrestricted - which means the low end you thought was enough (or too much) suddenly disappears - because it's not reflecting off things and not being transmitted to other rooms and through the ground.

When I was in a dance band we had 2 15s and 2 double 18s. That was perfect for dance clubs, but outdoors it could barely hold up. The last band I played a big outdoor venue with used what was essentially 2 PA systems - 3 18 subs, and 4 mains (two were 12s, and two were 15s because that what we had).

I could hear it 50 yards away, but it was simply "sound" at that point - up close to the stage it was all sub because the mains were set so wide...but we had plenty of stage volume too. People at the stage front basically got the on stage mix and bleed from our monitors.

Sants's post above really sums it up well. Better to have more than you need than not enough, and it's great to be "scale-able" if you can afford to.
 

HoboMan

Gold Supporting Member
Messages
19,273
I play in several bands with different PA setups.
On band has only one 15" sub with 12" mains and it kicks ass at small clubs and bars but we haven't done anything larger than that yet with that system.

Other two bands both use a pair of 18" powered subs (my system gets used with one of the bands) and we've done several outdoor gigs.
I wouldn't want to play those gigs with only one 15" sub.
I would rather have more PA than needed than trying to push a PA at the peak of or beyond it's limits.
 

stevel

Member
Messages
15,780
I find PA systems to be frustrating. I was reading one forum where a DJ showed his rig of 4 KW181's and what looked like 8 speaker tops and he said that's good for 200-300 people venues. Maybe I am crazy but that seems like overkill by a wide margin.

Well, first I think people think running PA is actually "easy". They think it's set a speaker up and play music through it. It's not quite that simple as you're discovering. Great live engineers really understand all the hardware and acoustics. That's why venues need specific systems designed for them (or else you have the old nest of bullhorns in the middle of the arena under the scoreboard cluster sound!).

One thing is clear: If you have a system that will handle 250 people maxed out, what do you do when there are 300 people?

PAs are not guitar amps where you turn them up to get overdrive. That's bad in PA. You want it CLEAN and for that you need either more power, or more speakers to cover more area. That's what the DJ is doing. However I'd also say forget DJs. You need band PA and that's a different animal.

I actually would have told you on first instinct you need 2 15s and 2 double 18s for a rock band.

Scale it down for the celtic band or smaller venues.

But since you have the 12s already, then a single 18 and rent a 2nd if necessary makes the most sense (practically and financially).

Think of it this way: Just because you have a speaker on stage, doesn't mean you actually have to use it! Heck, you can leave one in the trailer - less to carry in and out!

I think the problem is, people want to have two tops and two 18s, and maybe it's Farqwad syndrome or something, but they feel they *must* turn it up. They *have* to see how loud they can get it, or how much bass they can get, or "open her up".

It's no better than volume wars amongst bandmates...

It's not professional, and dare I say, juvenile.

There's no law that says just because you have 1000 watts that you have to use it. There's often like 10 points you can adjust volume between the source and speaker! No need to run things wide open.

It's simple, get more than you need, but run it at the correct volume for the venue. Things just sound so much better that way. You've got room to turn things up if you need, but you can always turn things down.

I've played gigs with 2 15s and double 18s where the PA was barely on.

I've played gigs with subs where the subs weren't even on, or had no signal going through them because they weren't needed.

Many times, we loaded in only 1 of the pair.

I've played gigs where the drums were just barely audible in the PA in the quiet room - all they needed was "spread" and not volume.

We had enough for big clubs, more channels than we needed, more wattage than we needed, and more of everything than we needed.

But, we could set all that up and turn it down or even off if necessary.

But you can't take two 10s on sticks and fill up a large venue.

But then there's this:

http://i.imgur.com/omwAT.jpg
 
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petty1818

Member
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4,362
Well, first I think people think running PA is actually "easy". They think it's set a speaker up and play music through it. It's not quite that simple as you're discovering. Great live engineers really understand all the hardware and acoustics. That's why venues need specific systems designed for them (or else you have the old nest of bullhorns in the middle of the arena under the scoreboard cluster sound!).

One thing is clear: If you have a system that will handle 250 people maxed out, what do you do when there are 300 people?

PAs are not guitar amps where you turn them up to get overdrive. That's bad in PA. You want it CLEAN and for that you need either more power, or more speakers to cover more area. That's what the DJ is doing. However I'd also say forget DJs. You need band PA and that's a different animal.

I actually would have told you on first instinct you need 2 15s and 2 double 18s for a rock band.

Scale it down for the celtic band or smaller venues.

But since you have the 12s already, then a single 18 and rent a 2nd if necessary makes the most sense (practically and financially).

Think of it this way: Just because you have a speaker on stage, doesn't mean you actually have to use it! Heck, you can leave one in the trailer - less to carry in and out!

I think the problem is, people want to have two tops and two 18s, and maybe it's Farqwad syndrome or something, but they feel they *must* turn it up. They *have* to see how loud they can get it, or how much bass they can get, or "open her up".

It's no better than volume wars amongst bandmates...

It's not professional, and dare I say, juvenile.

There's no law that says just because you have 1000 watts that you have to use it. There's often like 10 points you can adjust volume between the source and speaker! No need to run things wide open.

It's simple, get more than you need, but run it at the correct volume for the venue. Things just sound so much better that way. You've got room to turn things up if you need, but you can always turn things down.

I've played gigs with 2 15s and double 18s where the PA was barely on.

I've played gigs with subs where the subs weren't even on, or had no signal going through them because they weren't needed.

Many times, we loaded in only 1 of the pair.

I've played gigs where the drums were just barely audible in the PA in the quiet room - all they needed was "spread" and not volume.

We had enough for big clubs, more channels than we needed, more wattage than we needed, and more of everything than we needed.

But, we could set all that up and turn it down or even off if necessary.

But you can't take two 10s on sticks and fill up a large venue.

But then there's this:

http://i.imgur.com/omwAT.jpg

Well said and a great diagram! I guess for me, there's a few things I need to consider. First, I would love two 15s as mains, heck, I would even like two KW122's as an upgrade to my K12's. The problem is that in my groups, I buy the gear and I store/pack up all of the gear so I need to think about space and weight. The K12's sound great and they are light, that's a big selling point. If they sounded like garbage I would go heavier but they sound great, the weight is just a plus.

Secondly, we have been playing with two K12's for a few years now and it has been fine, I have just always wanted a sub. I don't feel that I really ever drive them, even in the rock band. I guess what I am saying is, I have never been in a situation where I felt the two K12's sounded too driven, even outside. What I mean by outside is a smaller stage where people sit out front. Nothing massive where the volume needs to carry. I do miss the bass in those situations though.

Thirdly, I am just trying to decide if I need a sub, that's why I thought one would be more than enough. I do run some bass and the kick drum through the mains and don't really want to damage them so I thought a sub would help. I just worry about switch both k12's to ext sub, losing the bottom end from them and then not having a sub that can fill in that lost bass.

Random question, mixing up mains seems like a band idea but what about subs? If I had a Kw181 for example and a smaller, more light weight 15" sub with the same wattage, would that sound weird? I am just really trying to avoid carrying two, 90lb subs.
 

HoboMan

Gold Supporting Member
Messages
19,273
Well said and a great diagram! I guess for me, there's a few things I need to consider. First, I would love two 15s as mains, heck, I would even like two KW122's as an upgrade to my K12's. The problem is that in my groups, I buy the gear and I store/pack up all of the gear so I need to think about space and weight. The K12's sound great and they are light, that's a big selling point. If they sounded like garbage I would go heavier but they sound great, the weight is just a plus.

Secondly, we have been playing with two K12's for a few years now and it has been fine, I have just always wanted a sub. I don't feel that I really ever drive them, even in the rock band. I guess what I am saying is, I have never been in a situation where I felt the two K12's sounded too driven, even outside. What I mean by outside is a smaller stage where people sit out front. Nothing massive where the volume needs to carry. I do miss the bass in those situations though.

Thirdly, I am just trying to decide if I need a sub, that's why I thought one would be more than enough. I do run some bass and the kick drum through the mains and don't really want to damage them so I thought a sub would help. I just worry about switch both k12's to ext sub, losing the bottom end from them and then not having a sub that can fill in that lost bass.

Random question, mixing up mains seems like a band idea but what about subs? If I had a Kw181 for example and a smaller, more light weight 15" sub with the same wattage, would that sound weird? I am just really trying to avoid carrying two, 90lb subs.

Find a place where you can rent a sub (or two) and try using different ones at gigs. Then you'll know what will work best for you before you buy.

Once you use a sub you'll probably never want to gig without one again. I bring at least one to even the smallest honky tonk bar gigs. It's not for the volume, it's for the low end "feel".
One of my bands had a regular gig at a tiny biker/honky tonk bar. We played many gigs without subs one gig we brought two and used them.
People who came to see us all the time kept commenting on how good we sounded that night. These were people who didn't know anything about PA gear, let alone what a sub was.

From that tiny hole in the wall club we got a lot more gigs from people hearing us play. We booked a high paying wedding, a couple of festivals and got a regular gig at another club.

After that gig I swore I would never gig without a sub again.
 




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