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crackinhedz

Missing frequencies

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Not sure how to explain what Im experiencing...but it seems that when running sine wave freq sweeps my system drops out about the 57-63Hz. Very annoying, and cannot seem to find a way to fix.

I have 6.5 coponents in the doors (stock locations) and a 15" Xcon ported (tuned to 32Hz), doors have been sound deadened (dynamat,mlv etc)

I have tried using different crossover settings (50,63,80,100HZ etc) to separate the sub and components, I have tried letting the sub only play these freqs, tried the components only, tried to EQ (my HU only allows 40,80...)

Im just baffled...could this possibly be a Null from my listening position? Maybe the components being too far off axis?

Every freq above and below seem fine.

Any thoughts?

Edited by crackinhedz

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what are the current highpass and lowpass crossover points and slopes for your components and sub? 

what tuning do you have available? 

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what are the current highpass and lowpass crossover points and slopes for your components and sub?

what tuning do you have available?

right now I have the components at 50Hz and the sub at 63Hz...after trying anything I could think of, I settled here.

Right now im using the Pioneer HU eq which allows eq adjustment at 40Hz, 80hz, 200Hz...) and crossover settings for the components of 'off, 50Hz, 63 Hz, 80Hz, 100Hz...and sub crossover of 63Hz, 80Hz, 100Hz....

I have an Audison BitOne, thats not installed...been contemplating selling...but maybe it will help?

Edited by crackinhedz

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I just find it odd that my 15" Xcon playing these freq's by itself has this problem...I could understand 6.5" in the door not handlng it, but the sub too?

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Im not sure what slope degree the HU uses for its crossovers...but at the amp I left them open, basically just using the HU crossovers.

Edited by crackinhedz

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set the lowpass on the sub to 80 or 100 and verify that all eq is disable (no bass boost, etc), is the null still present? 

 

other things to try, move the enclosure around in the trunk. 

 

edit: you can also sit in different seats and test if the null is present elsewhere 

 

edit2: i should've mentioned, disable the components for now. if they were causing cancellation with the sub that would be one thing but you've said its present with just the sub playing 

Edited by lithium

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Are all of the subs and speakers playing when you are testing?

If so I'd suggest you try flipping the phase of the sub, see what happens.

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Are all of the subs and speakers playing when you are testing?

If so I'd suggest you try flipping the phase of the sub, see what happens.

that's what I would suggest.

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Yeah, Ive tried pretty much everything I could think of. Even reversing phase of the sub...im just baffled. Thankfully its just a small band of frequencies albeit any missing freq sucks. I really don't notice it playing music, just playing tones since I know it happens its buging me.

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Leave subs off and try flipping one mid, then wire it back in proper polarity and reverse the other mid.

An RTA would be monumentally helpful as well.

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i experience the same thing right at 65hz on my Fi SSD15. I believe it's because my subwoofer is firing up and the port is firing back, creating cancellation in the trunk because of the size of this particular wavelength and the fact that there's only about 3 or 4 inches of clearance between the woofer cone and the trunk roof. 

i moved the box all the way to the back of the trunk near the tail lights and the cancellation problems improved quite a bit, but i lost a lot of SPL. what is your sub/port orientation?

Edited by midnightE39

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i experience the same thing right at 65hz on my Fi SSD15. I believe it's because my subwoofer is firing up and the port is firing back, creating cancellation in the trunk because of the size of this particular wavelength and the fact that there's only about 3 or 4 inches of clearance between the woofer cone and the trunk roof. 

i moved the box all the way to the back of the trunk near the tail lights and the cancellation problems improved quite a bit, but i lost a lot of SPL. what is your sub/port orientation?

how's port forward  or to either side?

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lithium, on 24 Sept 2013 - 23:23, said:

midnightE39, on 24 Sept 2013 - 22:49, said:

i experience the same thing right at 65hz on my Fi SSD15. I believe it's because my subwoofer is firing up and the port is firing back, creating cancellation in the trunk because of the size of this particular wavelength and the fact that there's only about 3 or 4 inches of clearance between the woofer cone and the trunk roof.

i moved the box all the way to the back of the trunk near the tail lights and the cancellation problems improved quite a bit, but i lost a lot of SPL. what is your sub/port orientation?

how's port forward or to either side?
didnt try side, sup up port forward had the best transient response in my trunk but i lost a ton of spl especially on the bottom end.

this is with the enclosure all the way back towards the tail lights

http://www.soundsolutionsaudio.com/forum/topic/60149-i-did-something-wrong-with-my-box-ssd15/?p=1017262

I'm considering doing this without the bandpass part, just turning the port at the sky hole to around 34-37hz, any objections? Not sure how my driver would perform in a bandpass but Fi said don't seal it up without high qts option.

Edited by midnightE39

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Midnight, that is an interesting suggestion. My port is to the side, and sub to the rear.

 

 

After reading through your thread, sounds exactly like what Im experiencing! very strange to say the least.

Edited by crackinhedz

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I'm certain now after moving my box around that it's an issue of cancellation. Sub up port back in a trunk is apparently not a good orientation. Of course there is always cancellation caused by something, but with my old setup (2 CVR 12's ported @ 40hz sub and port on the same side) there was very little noticeable cancellation when I had them faced straight forward port facing the ski hole; with the sub and port to the back, they were boomier and seemed less responsive, but overall there wasn't a huge difference either way. 

I'm just hoping that when I rebuild, aiming the sub back and port back, it solves the issue. I wanted to face the port towards the ski hole but not seal it up to it, but the general consensus here was that that was not a good idea either.

 

What i'd like to try is sub forward, facing the ski hole with the port back. without sealing off the trunk. there are openings in my rear deck to allow some of the bass into the cabin but they aren't very big, but i noticed more "high" bass when the old setup had the woofers and port facing the ski hole, and they were about halfway back inside the trunk because the box was too wide to go all the way back, however it was 2 woofers so they were in such a position that they might have "bounced" bass off the back of the seats and i was mostly hearing what was coming from the port.

 

with my single woofer setup, sitting cone forward at the ski hole and port to the back, i'd bet i get better transient response perhaps at the cost of a little low end spl.

 

is there any way to predict what sort of cancellation different orientations inside a given trunk space could create?

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