21 replies to this topic

[TagUrToast]

Hi,
I have a 4 ohm 2x2ohm DVC (stable, will not dip below 4ohms for 20-80hz) subwoofer that I want to use with a crown XLS-802.
I have noticed that it's not recommended to run the amp at 2 ohms per channel due to excessive power draw and heat, Would these issues still occur with a 240v/50hz mains?

Otherwise my only other option would be to connect the subwoofer to just one channel of the amp. What's the rated power @ 4 ohms if only one channel is driven? still 800w?

Thanks for your help

[dakos]

For only one channel driven at 4 ohms you might get 50-100W more output, not relevant at these power levels. What driver are you pushing?

The power consumption will go up as well at 240V.

[TagUrToast]

A Creative Sound Solutions SDX 15 subwoofer.
http://www.creatives...data-121107.pdf

[dakos]

This looks like a car audio subwoofer, pretty low sensitivity...

[TagUrToast]

Home theatre Sub not a car sub, designed to go to lower frequency's than most pro subs.

[dakos]

Interesing, what cabinet you put it in? Is it like the Lab Sub?

If it's for home usage then it's allot of power but you might have a big house
If you need more power then you might consider adding another sub, you already have an amp with one channel free. This way you also gain 3dB for doubling the membrane area and 3 dB more for doubling the power, that's a very noticeable volume gain.

[TagUrToast]

it's in a 19" cube sealed box (was more of a diy/hobby type project really) I use it with a Behringer iNUKE NU1000 that I got for $99 because it had a scratch on the faceplate but I am borrowing a Crown XLS 802 off a friend to use for a house party. The behringer is alright for ~250w or less volumes but once you get to about 500w, the sound starts to get less punchy and more muddy. I borrowed a EV P3000 off a friend for a weekend and had a play around with that and it was REALLY nice but it's out of my price range haha.

I'm a student, I had no money in the budget for a crown amp after I finished the sub.

[Deromax]

Dakos, a lot of home theater enthusiasts have recently discovered the benefits of pro amps for home audio duty.  The amps packs 10 time more power for the same price than the "hifi" boutique amps.  Big subs are the rage in the HT/DIY world.  For the longest time audiophiles have tried to reproduce all of the audible spectrum.  For the last 5 years, reaching 10 Hz at reference level is the new goal, believe it or not!  This means massive subs and potent amplification.

So the original poster's kind of message is more or less normal in forums like this one.  Pro amps are not only used professionnally anymore and home user will seek answers here.

I am personnally running a Crown K2 on two 15 inches subs in my place.  The setup would be killed in seconds if used in a live sound application, but for movie content, it will rip the drywall appart with subsonic content!

Pro audio, home audio, car audio...  we're all friends in the end!  

And for the original poster, I think the amp could survive in a home setup bridged at 4 ohms because the duty cycle is kinda easy.

[TagUrToast]

Deromax, on 09 August 2012 - 01:48 PM, said:

Dakos, a lot of home theater enthusiasts have recently discovered the benefits of pro amps for home audio duty.  The amps packs 10 time more power for the same price than the "hifi" boutique amps.  Big subs are the rage in the HT/DIY world.  For the longest time audiophiles have tried to reproduce all of the audible spectrum.  For the last 5 years, reaching 10 Hz at reference level is the new goal, believe it or not!  This means massive subs and potent amplification.

So the original poster's kind of message is more or less normal in forums like this one.  Pro amps are not only used professionnally anymore and home user will seek answers here.

I am personnally running a Crown K2 on two 15 inches subs in my place.  The setup would be killed in seconds if used in a live sound application, but for movie content, it will rip the drywall appart with subsonic content!

Pro audio, home audio, car audio...  we're all friends in the end!  

And for the original poster, I think the amp could survive in a home setup bridged at 4 ohms because the duty cycle is kinda easy.

Exactly, basically everyone posting in the DIY Speaker/sub section at hometheatreshack http://www.hometheat...diy-subwoofers/ are either using very high wattage plate amps (500-1000w) or pro amps for their subs. Behringer products are commonly used as they are so cheap and reliability is usually not an issue.

Yeah, Home theatre designed subwoofers are designed to go as low as possible and usually feature huge excursions ranging from 10mm-2" (One way). Efficiency is not a primary concern when designing HT subs.

Hmm ok, I think I may just have to give it a shot and see how it goes. Have you had any personal experience using 4ohm bridged loads on the old XLS series?

[dakos]

Dear Deromax and TugUrToast,
We are all good friends or very close relatives, 20 years ago I used to own a custom car audio shop before going pro
The LabSub example I gave a few posts up is exactly that, the DIY section on ProSoundWeb.com forum dedicated to self building a very low frequency cab for HT usage. I was just curious about the cab you are building
I still think it is allot of power for HT subs but then again I never had the pleasure of watching a movie in a place that has such high powered subs.
I would also give it a go at 4 ohm bridge since you already have the gear you have nothing to lose.

[Deromax]

I have never used the old XLS.

For the sake of discussion, I have used the CE, K, MT, MA, DC300 and the new XLS at some point, at work or at home!  I like Crown but I'm not brand exclusive.  At my venue we runs QSC PLX on the PA and XLS 1500 on monitors.  I also occasionnally rent a bigger PA with Lab Gruppen and a DJ rig with Crest CA.  I have used Peavey, EV, Behringer, Ashly, Yamaha P-S, even a *beep* Phase Linear 400!  They are all useable really, when well matched to the application.

At home I have some (olds) Brystons along the K2.  In the car I have 2 Pioneer Premier amps.  But I disgress!  

[TagUrToast]

I don't have the amp yet, will be getting it in a few weeks. I'll definitely give it a shot. It sounds like the chances of permanent damage are pretty low, just overheating and excessive power draw :S
If you're interested Dakos, here is a link to my facebook build log :

http://www.facebook....=3&l=e0bb21122c

I could have built a lower frequency box but at the time I was scared of tearing the surround so decided to go sealed, If I were to do it again I would go with a ported design as they tend to be more efficient and go lower (to a point). Although I have heard on some HT forums that sealed boxes seem to "feel" louder/more violent and ported boxes are less violent but sound louder.

I'll be using it with a DRPA and some DIY mid-boxes that I made a few years ago and if I can manage to find them somewhere, I had some older DIY-Bookshelf speakers with a fairly nice dual tweeter design that I might set as high boxes

Complete setup will consist of:
Something to feed the DRPA with a +4dbv signal (not sure what I'll use atm)
Driverack PA

---"Lows" - Crown XLS-802 - CSS SDX15 (as mentioned in this thread) - 30-90hz
---"Mids"  - Either a Behringer iNUKE NU1000 or an Australian Monitor KA800 - 4x 8 ohm DIY Mid boxes - Probably 90hz-2khz
---"Highs" - Either a Behringer iNUKE NU1000 or an Australian Monitor KA800 - 2x 16 ohm DIY High boxes - Probably 2khz-infinite
I'll probably end up changing the freq range of the mid's and highs and possibly overlapping them.

[dakos]

I wouldn't overlap the frequencies of the crossover zone because of combing effect unless there is a specific, very wired problem I'm trying to solve, also that dual tweeter design might also produce that unwanted combing effect so if things don't sound the way you want, I'd just disconnect one tweeter leaving one operational HF driver per channel.

One more thing about bass enclosures, the higher you climb in the order of the cabinet design, the more it loads the membrane of the speaker and thus lowering cone movement while at the same time expanding the frequency response of the driver at a small cost of loosing the tightness of the bass. That statement is true if you stay above the tuning frequency of the box, very easily achieved using a crossover (your DRPA).

The box you built looks very nice, you have great skills

@Deromax:
Very impressive résumé, I have not used that much of a verity of gear, back when I started to go pro I used very heavy Peavey and Crest gear, Peavey, EV, EAW and CV drivers at different times in my career, now I have a few Crown amps and I'm interested in getting a JBL rig but that's not in the near future.

What types of gigs are you usually handling? Live shows? DJ's?

[TagUrToast]

@Dakos
Yeah I'm planning to have about a week of tinker time to adjust it to something that I like. I'm just going to go off what sounds nice across a few different varieties of songs.
From memory, it's actually two different tweeters, one is a dome tweeter and one is a two inch standardish looking tweeter (looks like a small midrange type design) and they are both on different outputs of the crossover so I assume that they are getting different frequency's.
Yeah I am familiar with that, I don't actually own a smart variable crossover so that was another reason why I went sealed over ported. It's not my DRPA, it's just one that I can get my hands on for a few weeks.
Thanks haha, I actually used no power tools (no circ saw's or anything, didn't even have a battery drill for doing the screws up at the time) other than a jigsaw for the curves and fiddly bits.

I wish I still had access to a EV P3000, makes my sub rock hard haha
I'm going to have to think of something elaborate to manage the power for this, there will also be 700ish watts of LED's that will need to be powered + 500-1000w of other electronics.

[Deromax]

I have done several kind of related work in the past and still try to expand my experiences.  I started a mobile DJ service when I was 14, back in the mid 80s.  I had DIY speakers made of Radio-shack parts!  I began more serious audio work in the early 90s at college.  Now, my day job for the last 17 years is running an audiovisual department in a high school, were we have a 500 seats venue.  We have mostly students shows but sometime have regionals touring acts.  We're also hosting some dance nights each years and we install big sound/lighting/video rigs so guest DJs can put out impressive shows. These are not our father's discos!

I can do sound, basic lights, camera work, recording, editing, some maintenance, management and of course I'm training my student helpers!

Beside work, I'm into speaker building, home theater and car audio!

TagUrToast, is it a WinISD graph I see in your original post?  If you use this software, you should be able to plot an excursion curve that will tell you how a driver will react at a given power, and the effect of any EQ, crossover or subsonic filter you will implement.