Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Dan Whitney]

I apologize in advance for the noob question which I will get to in a minute.  First some background.  I am starting the process of researching active subwoofers that will compliment my DSR112s for my weekend warrior rock band.  From what I’ve read on the forum 15” will suffice but 18” is the way to go considering the difference in box size and weight is minimal compared to the extra air displacement of the 18” woofer so 18”s are my 1st choice.  A dual box is more cost effective but transportation of one just wouldn’t work for me and I like the idea of scalability with 2 individual subs.  I could keep it simple and just go with the DXS18XLF but I would like to keep my options open in case I run into a sale or gently used subs that would also fit the bill.  That being said finding a pair of matching used subs is harder than it sounds.       

To the point, when considering subs should I match the wattage output of the subs to my tops or do I need to double the sub wattage?  I ask because bass amps seem to require more wattage to keep up with a guitar amp of lower wattage so I assume the same principle applies to a PA system.     

[Mal Brown]

I've been playing around with DsR-112 over QsC KW-181.

The DSR crosses at 120.  The QSc crosses at 100.  To get them sounding better I bumped 100hz and 125 hz on my Main out's EQ.  They actually sound pretty good to me that way.  I also used a behringer reference mic.  The one suggested for a room EQ Wizard.   It's a decent mic for low dough...  That mic was run into a Soundcraft UI 24.  I downloaded a pink noise sample and ran that to get an idea of what was going on.  There was a pretty big hole in that 100-120 range.  After filling it with  2, 2.5 db bump my ears told me that things were improved.

Don't laugh but I was using Friend of The Devil era Grateful Dead as my a music test.   There is a metric ton of acoustic stuff going  on and Phil's bass has very clear and emphasized upper mids.  I've been listening to that stuff for a couple of weeks as I learn some of it.  So I am very familiar with it on K140's.  I got tired of not being able to fill GD requests.  Out here in the Cascades, the Fead are still very popular...  Rather different from my typical test tracks.  I also used some later Steely Dan, Bonnie Raitt and Bonedaddies.  All material I am familiar with.

So not a super technical methodology and one largely dependent on my ears.

I certainly wouldn't buy KW-181's at this point unless it was a smokin' deal... 

I think option already know the answer.  Buy the Yamahas.  7 year warranty, 1 vendor integrated system...  not inconsequential factors ...

Rule of thumb for me is inside, venue depending 1 sub or 1 sub per top works,   Outside, 1 to to two subs.

I will probably move my KW-181's - not on a smokin' deal ;-)  I will very likely go DIY and external processing and power.   I will investigate the DXS 18 XLF before making that call though.  The reasons above are less compelling for me as subs will have to integrate with Yam DSR-112, DZR-315 and db tech Ingenia IG3T.   If the sum of the on board DSP functionalities are suitable though, the Yam's could still be a viable option.

[Dan Whitney]

Don't laugh but I was using Friend of The Devil era Grateful Dead as my a music test.   

Rule of thumb for me is inside, venue depending 1 sub or 1 sub per top works,   Outside, 1 to to two subs.

Oh I like the Dead.  We just don't play any of it.  One sub is more than enough for the indoor venues we plan to play at.  In fact, we really don't need one for those places.  The drums can carry the room as it is and I'm not running my bass through the PA.   However, it does help with break music and gives us the option for the drummer to use his electric kit vs his acoustic kit for better volume control.   Outdoors I agree, you can get buy with 1 but 2 just sounds fuller. 

[Paul G. OBrien]

To the point, when considering subs should I match the wattage output of the subs to my tops or do I need to double the sub wattage?

No... wattage is not the spec you need to focus on. A system that sounds balanced has subs with the capability to produce about 6dB more SPL than the mains. This is very much genre specific... some DJ genres may require 10-20dB more subbage , but for R&R I think 6dB is a good number. If you search for other threads on the DSRs you will find many comments that they are capable of hanging with a pair of 18" subs when used to thier full potential.

[Brian Jojade]

To the point, when considering subs should I match the wattage output of the subs to my tops or do I need to double the sub wattage?  I ask because bass amps seem to require more wattage to keep up with a guitar amp of lower wattage so I assume the same principle applies to a PA system.   

There is no such thing as wattage output.  SPL is your output.  How much power you need to make that happen depends on the speaker and frequency you are dealing with.

As Paul pointed out, it's often desirable to have a system that can produce more SPL on the low end, as that seems to be what people like these days.  Yes, all things being equal, it takes more power to produce SPL at lower frequencies. But in speakers, all things are never really equal.

If you're matching power amps to cabinets, making sure you have enough power to get the performance out of the cabinet you need, but not too much power as having a simple mistake capable of blowing things up is the ideal range.  The 'too much' power level is very dependent on the competency of the operator.  A qualified operator can safely use an amp that is 2-3X the rated RMS of the speaker it's driving.  A DJ that likes to run everything full red all the time would need an amp rated at 50% of RMS to be safe....

[Dan Whitney]

Ok glad I asked.  Yamaha's published specs put the DSR112s max SPL at 134db.  Based on my initial search I'm not seeing any subs in my price range spec'd at 140 SPL. 

Yamaha DXS18XLF and the QSC K118 are rated at 136 SPL
JBL PRX818XLFW = 134 SPL
JBL SRX818P = 135 SPL

Considering how loud the DSR112s are I don't see me ever needing to run them that hard.  They are loud as all get out with the speaker levels on the back of the box at 50%.  With that being said, it sounds like I should be ok as long as the subs at least match the 134 SPL but preferably exceed it?   This is assuming I'm not running the DSRs at full tilt. 

[Jeff Bankston]

I have 18" , 12" , 2".  18" is powered by 1700 watt amp. 12" is powered by 550 watt amp. 2" is powered by 100 watt amp. Crossover points are 130hz , 1500hz. I used an spl meter and frequency test tones to get the right balance between drivers.

[Dave Garoutte]

Considering how loud the DSR112s are I don't see me ever needing to run them that hard.  They are loud as all get out with the speaker levels on the back of the box at 50%.  With that being said, it sounds like I should be ok as long as the subs at least match the 134 SPL but preferably exceed it?   This is assuming I'm not running the DSRs at full tilt.

That knob adjust the input sensitivity of the DSR, not it's ultimate output.
50 just requires more input level to reach a given output level than 100.
It's ultimate volume potential is the same at any setting.

[Dan Whitney]

That knob adjust the input sensitivity of the DSR, not it's ultimate output.
50 just requires more input level to reach a given output level than 100.
It's ultimate volume potential is the same at any setting.

Well I'll be damn.  I guess I misread that in the manual. Thanks for clarifying. 

[Tim McCulloch]

Watts don't make sound, voltage does.

How much power you need for each pass band depends on multiple factors.  There is no simple "one number" spec.

[ProSoundWeb Community]