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Subwoofer problem (not performing like it should)

post #1 of 19
11/17/12 at 3:36pm
Thread Starter 
Well, God bless you audiophiles! I have recently become addicted to great sounding audio and building with wood so I have just built some speakers (for home theatre and listening to music) My setup is like so: I have 2x - .71 cu ft. monitor speakers with 6.5" visaton woofers and goldwood piezo tweeters. They sound good being driven by a Crown XLS1000 amplifier.

Here's where I'm stuck. Based on reading all of these positive reviews on parts-express.com for the 15" Dayton Audio Classic Subwoofer for $89 I decided to build a custom box like others have with positive results and bought the sub. I tried hooking up the sub to my crownXLS1000 once I had the sub all screwed into the enclosure (8.26cu ft. with 2x -4" ports tuned to 21hz) and it just isn't performing! I tried everything I can think of to get this puppy working! I thought for sure it was a damaged woofer and parts express sent me several different subs because we both figured the sub was damaged during shipping causing the cone to sieze up. So the speaker will play and will get loud but it's not putting out any "bass" and shaking walls like all the reviews are saying it should with only 100 watts. I give it like 350 watts (amp turned all the way up) and then it starts shaking some stuff in my room but sounds horrible and distorts on the loud bass notes and drum hits. I don't know what's going on here. I tried every possible angle (wiring connections, different channels on amp, different subs). Here are some reviews on parts express which have me believing this sub should be absolutely pounding and shaking down the house at lower level.

"In a 7 cubic foot box tuned to 20hz the excursion peak above the tuning frequency is at about 32hz. You can give it about 125 watts before it exceeds its rated Xmax. With 250 watts input the driver is at about 12mm which SHOULD be within safe limits of the driver but that is just a stab in the dark. I ran mine free air at 20hz and it looks to do more then 1" peak to peak but I ran out of amp power (100 watts) before I could get the driver to bottom!!!"
-mtg90

"I just picked up 4 more of these on the daily special sale.Nice woofers, the first ones I had gotten and broke in at 20hz in free air.Boy do these jump! I would say a inch+ peak to peak.This is likely out of the voice coils xmax range but the raw excursion is there.
I have two 9.2 cf enclosures tuned to 19hz.f3@ 19.25 hz(winisd alpha). Im working on 4 more,considered isobaric arrangement.I plan to run the buttkicker home amp.(I believe Dayton underates wattage, or is one of the only companies with honest power ratings)I think they could handle 250 watts all day long. My daughter was impressed that she could feel her clothes shake at the distance she was from the speakers. Hits very low,smoothly on notes without boominess.Good value!"
-Wickedwolf - 06916

When I ran this sub on the Crown XLS 1000 "free air" it is not moving or getting even close to 1" peak to peak at 100 watts. I have to crank it to like 350 on my amp before it even gets close and then it starts distorting. This is the fourth sub parts express has sent me so I just can't believe it is the sub. It will play music just not sounding like it should I believe from all the other reviews. Also the amp I believe is putting out recommended wattage because hooked up to my other monitors they are acting like they should. Am I missing something here? Anyone know what's going on and why my sub isn't acting the way it should?

Thanks for any and all help!
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post #2 of 19
11/18/12 at 7:58pm
That's odd. Do you have any high pass filters accidently in place that could cause it to not play bass?
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post #3 of 19
11/18/12 at 10:22pm
Hey I know you smile.gif

That is weird, what is your signal chain? Or more specifically how are you feeding the XLS amp?

Also are you sure that you don't have any of the crossover settings on the XLS turned on?

I am with Loonybomber, It does sound like you have a highpass swiched on somewhere.
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post #4 of 19
11/19/12 at 12:26am
does the crown display read... bypass or lowpass or highpass.
I had a similar problem with my crown and I was scratching my head all over wondering why on earth it dosent play any bass? It was only when i disconnected my mains and played only subs, I could hear human voices from my sub and i was like....damn!!! biggrin.gif
My crown was on highpass mode.

Also, I had to give a 12dB bump using my receiver. Without which the effects were kinda how you describe, without the distortion part smile.gif
I think if one runs audyssey it gives a 10dB bump for sub channel.

Also try Disconnecting the mains or play channel B if you have A/B such that only the sub plays.
Edited by ShaQBlogs - 11/19/12 at 12:38am
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post #5 of 19
11/20/12 at 6:50pm
How big is your room? Is it sealed off or does it open up to other rooms? Before we start going the troubleshooting route, we should find out if you're asking the sub to do too much.
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post #6 of 19
11/22/12 at 2:10pm
Thread Starter 
Hey mtg90, will you tell me how you have your setup when you are testing 'free air' to get that much excursion with only 100watts? I have my audio player (ipad or mp3 player) ---> CrownXLS1000 amp
> Sub. I have the volume all the way up on music device and then i have to crank the amp almost all the way up to get it to start getting that much excursion and then it starts distorting.
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post #7 of 19
11/22/12 at 2:13pm
Thread Starter 
My room is pretty big and it is sealed. 11ft X 21ft X 7.5ft tall
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post #8 of 19
11/22/12 at 2:16pm
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The Crown amp is set how it should be I believe .... Either on "stereo bypass" (sending all frequencies) or "stereo lowpass" (set at about 90hz). And I only have the sub connected (no other speakers). I've also tried channel 1 ... then channel 2 ... and then I tried bridge mode and it acts the same every different way.
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post #9 of 19
11/22/12 at 2:17pm
Thread Starter 
Quote:
Originally Posted by ShaQBlogs View Post

does the crown display read... bypass or lowpass or highpass.
I had a similar problem with my crown and I was scratching my head all over wondering why on earth it dosent play any bass? It was only when i disconnected my mains and played only subs, I could hear human voices from my sub and i was like....damn!!! biggrin.gif
My crown was on highpass mode.
Also, I had to give a 12dB bump using my receiver. Without which the effects were kinda how you describe, without the distortion part smile.gif
I think if one runs audyssey it gives a 10dB bump for sub channel.
Also try Disconnecting the mains or play channel B if you have A/B such that only the sub plays.

What is audyssey? and 12dB bump using receiver mean?
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post #10 of 19
11/22/12 at 2:32pm
i'm going to guess that you are not sending enough signal to your amp.

pro amps work on a different voltage than consumer gear. some consumer gear is good enough, some is not.

there are many devices that will step up the voltage between your reciever and the amp.
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post #11 of 19
11/22/12 at 2:51pm
Quote:
Originally Posted by andyba55face View Post

My room is pretty big and it is sealed. 11ft X 21ft X 7.5ft tall

1700 ft3 is actually on the relatively smallish side. I have a ~2300 ft3 room and can push a singlesmall sealed 12" sub to make the room shake. There may be other issues here. A large ported 15" sub should not have any problems. Have you tried using the sub crawl method to find the ideal spot for the sub? You might be sitting in a bass null spot. I'll assume your box has been built correctly to the proper size and the ports are the correct size and length for that driver.

Quote:
Originally Posted by andyba55face View Post

The Crown amp is set how it should be I believe .... Either on "stereo bypass" (sending all frequencies) or "stereo lowpass" (set at about 90hz). And I only have the sub connected (no other speakers). I've also tried channel 1 ... then channel 2 ... and then I tried bridge mode and it acts the same every different way.

The amp should be set to lowpass with the highest possible crossover frequency. Let your receiver/pre-pro do the actual crossover from mains to sub.

Quote:
Originally Posted by andyba55face View Post

What is audyssey? and 12dB bump using receiver mean?

Audyssey is a automatic room eq feature available on some receivers/pre-pros. It is used to automatically correct your speakers' frequency response as it interacts with your room. It will correct for phase, distance and frequency spikes and dips based on measured responses from your speakers in your room. There are different levels of Audyssey from the entry MultEQ on up to the Pro level (which requires an additional cost and not all receivers/pre-pros are capable of this add on). THere are other competing products like ARC, Pioneer's MCACC and Yamaha's YPAO. Each has their own pros and cons.

12dB bump means they turned up the trim for that particular channel (sub in this case) up by 12dB.
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post #12 of 19
11/22/12 at 5:21pm
Thread Starter 
Would you provide such an example of a quality device that would do this?
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post #13 of 19
11/22/12 at 5:26pm
Thread Starter 
Yea the bass is way louder in one spot of the room... Haven't done much "crawling" with it bc it's so huge and heavy lol 8.26 cubic foot with 2x 4" ports 17" long (tuned to about 21 hz). Ya man I thought this enclosure and this 15 should have no prob shakin the room and the whole house for that matter but it just don't get barely loud before distorting and sounding horrible. Sounds decent at low levels and blends nicely with my other speaks.... But I can't turn it up too far or it starts cutting out...
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post #14 of 19
11/22/12 at 6:00pm
did you catch post #10?
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post #15 of 19
11/22/12 at 8:41pm
Quote:
Originally Posted by LTD02 View Post

i'm going to guess that you are not sending enough signal to your amp.
pro amps work on a different voltage than consumer gear. some consumer gear is good enough, some is not.
there are many devices that will step up the voltage between your reciever and the amp.

Quote:
Originally Posted by LTD02 View Post

did you catch post #10?

Very good point. It would be helpful to know what receiver the OP has. The Crown requires 1.4Vrms to achieve maximum power.

Quote:
Originally Posted by andyba55face View Post

Would you provide such an example of a quality device that would do this?

If you are referring to what receiver/pre-pro has room correction features, then there are many out there. Most of the Denon Onkyo, Pioneer, Yamaha receivers have some form of it. My favorite so far is the Denon 4311. There are others like Anthem, Harmon Kardon and Mark Levinson have it also, but I don't know how many in their lineup have it. This is not a comprehensive list, but just some examples of some that have this feature.

One other side note is that since you have a ported sub tuned to 21Hz you will need a HPF to prevent the driver from self destructing if fed too much power below that frequency.
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post #16 of 19
11/23/12 at 8:18am
Thread Starter 
Quote:
Originally Posted by LTD02 View Post

did you catch post #10?

yea that's what I meant by please list some quality products that do this (up the voltage or whatever) Sorry I should have been more specific
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post #17 of 19
11/23/12 at 8:20am
Thread Starter 
I don't have a receiver yet ... Just have my ps3 audio cables plugged into the crown and then the output on the crown going into another crown (XLS1500) If my ps3 isn't plugged into the amps then I just have a ipad or music (mp3) player plugged straight into the amplifiers.
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post #18 of 19
11/23/12 at 8:22am
Thread Starter 
Also, how do I build or where can I find a decent quality HPF to protect the sub ... also what hz should it be set at?
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post #19 of 19
11/23/12 at 2:47pm
it is starting to sound like you need a mini-dsp. i'm not sure which to suggest. it appears the balanced version outputs 2v which is enough to bring full power out of your amp. there are converter cables from phoenix to rca, so don't let the strange inputs scare you away.

it can provide the high pass filtering as well as a whole ton of other functionality, but i'm not the guy to ask about the mini-dsp.

place the high pass filter, 2nd order or higher filter, at or just below the tuning frequency of a ported sub.
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