[Brunt]

Hello,


I recently purchased a sub from in ID company and a reputable one at that. Try to picture this:


This company makes a wonderful ported 15" sub which is 500w. They do not normally make one, but they built me a custom 15" sealed sub in a 20" cube, powered by the same 500w.


After dialing it in and messing with settings, and even talking to the company...I come to this conclusion: I am completely underwhelmed by the sub's output. During the opening scene of my first movie test, there is a a bass heavy passage right after the opening credit. During this scene, before I could even feel or hear actual bass, I heard the driver knocking as it was being over driven. Keep in mind my sub gain was 12:00 and my AVR sub level was set at less than zero. So, after dialing it in per the company's instruction, the sub is now set so it won't make that noise...which is awesome...except that now the overall output and volume is almost worse than my old Polk PSW505. Put simply, as of right now I regret not just getting a second Polk!


My question to you guys is this: What would make this sub behave this way? Over powered? Underpowered? Keep in mind, the company does sell sealed subs, which usually have more power than their ported cousins...but mine doesn't. I know sealed subs offer less output, but I've read in numerous locations that sealed subs also off the advantage of being incredibly hard to over drive because of the pressure and force being applied to the backside of the driver and it not being able to escape through a port.


My room is 21'x12'x8'


Any thoughts would be greatly appreciated!!!

 

[dpc716]

I'm not an expert but I'll chime in anyway!


First of all its entirely possible, depending on the nature of the demo material you chose, that a ported 12" can play it as loud or louder than a sealed 15".


One thing that could cause you to overdrive your sub, despite the volume seeming moderate, is that it's in a bad spot in your room. Have you experimented with the phase settings, or tried moving it? What was a good place in your room for your Polk might not be a good one for your current sub.


If none of this works, try taking some measurements. You should get a SPL meter if you don't have one to find out if you are actually reaching the output levels you might expect given the sub's capability and your room size.

 

[Brunt]

I should clarify...ALL material at this point underwhelms, not just one scene. Music, movies...multiple scenes.

 

[Liquid$team]

It seems like u should not be able to over drive it. I'm gonna try to plug the ports on mine and juice up the volume to see if it does the same thing. If that is as loud as it goes then I suggest getting rid of it and getting 2 ported subs. Or keeping it as well as getting 2 ported subs since your room is so big

 

[craig john]



The difference between these 2 graphs is the setting of the Subwoofer Distance in the receiver. When the Distance is improperly set, the waves from the subwoofer and the waves from the speakers arrive out of phase and they cancel. That is what causes the huge 20 dB dip around the crossover frequency. The crossover is set at 80 Hz and the dip extends from 60 to above 100 Hz. That is the entire mid-bass range. The "sound" of this is exactly what you describe: completely underwhelming.


Try adding some distance to the Subwoofer Distance setting. The improvement seen above was the result of going from a setting of 10.4 ft. to a setting of 13.8 ft.


Craig

 

[Brunt]



Quote:
Originally Posted by craig john /forum/post/20815717

The difference between these 2 graphs is the setting of the Subwoofer Distance in the receiver. When the Distance is improperly set, the waves from the subwoofer and the waves from the speakers arrive out of phase and they cancel. That is what causes the huge 20 dB dip around the crossover frequency. The crossover is set at 80 Hz and the dip extends from 60 to above 100 Hz. That is the entire mid-bass range. The "sound" of this is exactly what you describe: completely underwhelming.


Try adding some distance to the Subwoofer Distance setting. The improvement seen above was the result of going from a setting of 10.4 ft. to a setting of 13.8 ft.


Craig

i will try this when I get home tomorrow. Funny, Audyssey originally set the sub's distance to something a few feet shorter than the frontstage that it sits next to. The company told me to change the sub's distance to match the frontstage, but I guess i will add some to that distance tomorrow and check for differences.

 

[Liquid$team]

Brunt, your Audyssey is turned off.

 

[Brunt]

Correct...My Audyssey is turned off per the companies recommendation....still underwhelmed.

 

[Mpray1983]

Im assuming your sub is from ED. Did they recommend the box size or did you tell them what size to make it. Turn audyssey back on and leave the settings as is, make sure you set the sub volume to 75db like audyssey tells you to. It is okay to turn the sub trim up after just dont touch the volume on the actual sub. How big is your room? Make sure dynamic eq is on (this will add in a house curve) and don't change the sub distance. Sub manufacturers sometimes add filters to their amps which will actually add distance to a subwoofer. My sub's now are set to 14.6th and they are only 10ft away. My paradigm sub was set to 26ft due to filters. Also make sure that you have your phase set to 0. If it is possibly try to place in a corner. Also what demo material were you listening to? Big subs like this are not going to make noise all the time Like your little sub. Instead they come alive when the time comes. Did you install all the pieces or did it come completed? It could be missing a connection internally. Possibly the negative has fallen off. You will still get power but it will sound pathetic. When you run audyssey and you can barely hear the subwoofer chirps don't worry about it not a big deal. Also change your crossovers to 80hz. For your fronts and center. Also make sure your LPF of LPE is set to 120hz. (this is different from the crossover) Do you have an onkyo or denon?

 

[craig john]

Another thing to try is shutting the speakers off and just listen to the sub. Walk around the room while listening to the sub. If the sound is underwhelming everywhere, you have a subwoofer problem. If the sound is better in some locations than others, you're likely dealing with a big null at the LP.


Of course, the ideal diagnostic tool will be measurements of the system.


Craig

 

[schan1269]

I have a feeling the box is too big and doesn't have enough back pressure to keep the subwoofer from bottoming. Same "problem" with IB designs.

 

[Mpray1983]



Quote:
Originally Posted by schan1269 /forum/post/0


I have a feeling the box is too big and doesn't have enough back pressure to keep the subwoofer from bottoming. Same "problem" with IB designs.

It's only 3cf tho and it is a 15 inch driver. There isn't many 15" drivers that 3cf would be too large for.

 

[craig john]



Quote:
Originally Posted by schan1269 /forum/post/20815968


I have a feeling the box is too big and doesn't have enough back pressure to keep the subwoofer from bottoming. Same "problem" with IB designs.

It's a 15" driver in a 20" cube box. Assuming 1" box material, that's a ~4 cubic ft. box. Not likely too big.

Craig

 

[craig john]



Quote:
Originally Posted by Mpray1983 /forum/post/20815929


...and don't change the sub distance. Sub manufacturers sometimes add filters to their amps which will actually add distance to a subwoofer. My sub's now are set to 14.6th and they are only 10ft away. My paradigm sub was set to 26ft due to filters.

Note that your Subwoofer Distance in both cases is longer than the actual, physical distance. The OP had his Subwoofer Distance set by Audyssey to less than the physical distance, and he changed it to equal the physical distance. I suggested he set it longer than that....


As you point out, latency in the subwoofer due to the filters and phase controls, etc., is the reason the sub needs a longer Distance setting.


Again, actual measurements are the only thing that will tell the whole story.


Craig

 

[Mpray1983]



Quote:
Originally Posted by craig john /forum/post/0



Note that your Subwoofer Distance in both cases is longer than the actual, physical distance. The OP had his Subwoofer Distance set by Audyssey to less than the physical distance, and he changed it to equal the physical distance. I suggested he set it longer than that....


As you point out, latency in the subwoofer due to the filters and phase controls, etc., is the reason the sub needs a longer Distance setting.


Again, actual measurements are the only thing that will tell the whole story.


Craig

According to audyssey if it does give you a reading of less than the actual distance you should change it to the actual distance.

 

[craig john]



Quote:
Originally Posted by Mpray1983 /forum/post/20816029


According to audyssey if it does give you a reading of less than the actual distance you should change it to the actual distance.

Actually, if Audyssey gives a Subwoofer Distance setting that is *less* than the actual, physical distance, you should figure out why and correct it... and than re-run Audyssey. It could be some mechanical interaction, between the mic and the room.


If one uses a mic boom to mount the Audyssey mic for the measurements, one should *never* get a reading less than the actual, physical distance. Audyssey is reading the "time" it takes for the subwoofer bass waves to move from the subwoofer driver to the mic. It can never take less time than the speed of sound would take to traverse that distance. If the Subwoofer Distance is measured at less than the actual subwoofer distance, there must be some mechanical connection between the sub and the mic that transmits the signal faster than the speed of sound.


OTOH, readings longer than the actual, physical distance are common, due to the latency issues previously discussed.


Craig

 

[Mpray1983]



Quote:
Originally Posted by craig john /forum/post/0


Actually, if Audyssey gives a Subwoofer Distance setting that is *less* than the actual, physical distance, you should figure out why and correct it... and than re-run Audyssey. It could be some mechanical interaction, between the mic and the room.


If one uses a mic boom to mount the Audyssey mic for the measurements, one should *never* get a reading less than the actual, physical distance. Readings longer than the actual, physical distance are common, due to the latency issues previously discussed.


Craig

So either the original poster is not using a boom stand or there is something going on in the room that is really messing with his measurements. I think that would definitely be the place to start trying to figure out this problem.

 

[craig john]



Quote:
Originally Posted by Mpray1983 /forum/post/20816119


So either the original poster is not using a boom stand or there is something going on in the room that is really messing with his measurements. I think that would definitely be the place to start trying to figure out this problem.

Yes. Please see Post #5 above.


Craig

 

[Mpray1983]



Quote:
Originally Posted by craig john /forum/post/0



Yes. Please see Post #5 above.


Craig

Then why did he not notice the same problem with his Polk sub? That is what makes me think it may be a problem physically with the sub.

 

[Brunt]



Quote:
Originally Posted by Mpray1983 /forum/post/20815929


Im assuming your sub is from ED. Did they recommend the box size or did you tell them what size to make it. Told them my size constariants and they "engineered" a box to match Turn audyssey back on and leave the settings as is, make sure you set the sub volume to 75db like audyssey tells you to. First, they told me to turn Audyssey off and how do I set the sub to 75db? I only have options for plus or minus 0.0. It is okay to turn the sub trim up after just dont touch the volume on the actual sub. How big is your room? Make sure dynamic eq is on (this will add in a house curve) and don't change the sub distance. Uh this again is the exact opposite of what the company told me to do. Sub manufacturers sometimes add filters to their amps which will actually add distance to a subwoofer. My sub's now are set to 14.6th and they are only 10ft away. My paradigm sub was set to 26ft due to filters. Also make sure that you have your phase set to 0. If it is possibly try to place in a corner. Also what demo material were you listening to? Big subs like this are not going to make noise all the time Like your little sub. Instead they come alive when the time comes. Did you install all the pieces or did it come completed? Sub came in one piece. It could be missing a connection internally. Possibly the negative has fallen off. You will still get power but it will sound pathetic. When you run audyssey and you can barely hear the subwoofer chirps don't worry about it not a big deal. Also change your crossovers to 80hz. For your fronts and center. Also make sure your LPF of LPE is set to 120hz. LPF is set to 80...per the companiy's instruction, will up it and see what happens I guess. (this is different from the crossover) Do you have an onkyo or denon?

I have an Onkyo. The original numbers Audyssey gave me were something like this: Distance to sub= 7.5ft...even though mains and center are next to it and they're set to 10ft. It also set sub to -12.5db's...which caused the sub to be almost nonexistant. Per company's direction, set sub gain in receiver to -4.5db