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1999 Jeep Wrangler TJ
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Discussion Starter · #1 ·
I've learned to accept that I have a null at 180hz. Nothing to do about it till I can either bring up some fabrication or replace some speakers, or sacrifice a goat to the right deity.

In the meantime, I'm curious what I'm actually missing. What does having a 6 to 10 decibel drop at the 180hz frequency actually sound like? A co-worker of mine that used to do professional installs said that it would leave my music sounding hollow, and I can see that. Anything else? I'm mostly just curious what I had to look forward to.
 

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Discussion Starter · #2 ·
I need the motivation so I can teach myself fabrication 馃ぃ
 
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I've learned to accept that I have a null at 180hz. Nothing to do about it till I can either bring up some fabrication or replace some speakers, or sacrifice a goat to the right deity.

In the meantime, I'm curious what I'm actually missing. What does having a 6 to 10 decibel drop at the 180hz frequency actually sound like? A co-worker of mine that used to do professional installs said that it would leave my music sounding hollow, and I can see that. Anything else? I'm mostly just curious what I had to look forward to.
It is a very important region of the audible spectrum as nearly all but some woodwinds and and other percussive instruments have fundamentals at or near 180 Hz:


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1999 Jeep Wrangler TJ
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Discussion Starter · #6 ·
I call it the meat. You will be missing the meat of your midbass.
Sure you can just add more potatoes but nobody like a flabby bottom end.
I had a feeling I was missing something important. I'm on keto so I'd rather focus on the meat most days 馃ぃ

JUNK!

time for a full rebuild!
I've recently given up my dream of a killer system using factory speaker locations 馃槥. I wish I had some space under my seats for midbass drivers 馃槙
 

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Discussion Starter · #7 ·
It is a very important region of the audible spectrum as nearly all but some woodwinds and and other percussive instruments have fundamentals at or near 180 Hz:


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Oh that's interesting! And annoying that I'm missing out on that! I'll have to Google what half of that means 馃槅
 

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2003 Jetta Wagon
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I've recently given up my dream of a killer system using factory speaker locations 馃槥. I wish I had some space under my seats for midbass drivers 馃槙
i found a great small enclosure build. this would fit darn near anywhere. 2018 Golf Sportwagen Simple Build - Page 2

Or Mr. Bateman has done a lot of work with 3" drivers and such. like maybe you cant fit a single 6.5 but you may be able to fit 2 3" under the seat.
 

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2004 Rav4 (2)JL900/5 MiniDsp 8x12(Dirac) LPG26NA GS25 Epique180-44 (2)Um12
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Oh that's interesting! And annoying that I'm missing out on that! I'll have to Google what half of that means 馃槅
The fundamental tone is the main tone. The
timbre鈥 is what creates the 鈥渟ound鈥 of say a piano. When a piano key is pushed, a string is struck setting it into a complex motion. The whole string vibrates in one big up and down, and within that 鈥渨hole鈥 vibration smaller sections vibrate. Those are the harmonics and they give the timbre.

Rectangle Font Slope Circle Parallel

Rectangle Slope Line Water Font


These harmonics are governed by mathematics and can be thought of as fractions. The same with a flute or French horn. The column of air behaves like a string except the air columns compress and stretch in those fractionally governed ways.

This is a little bit above my pay grade now but a subwoofers port can have these same 鈥渞esonances鈥 and have an effect on the sound. In winsid, when modeling an enclosure with a port, there鈥檚 a place that shows the 鈥1st鈥 resonance and in certain cases it can cause problems in the sound. It鈥檚 usually a moot point but just showing how the fundamental tone and it鈥檚 harmonics work in almost everything in the world, speaker cones included.
 

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1999 Jeep Wrangler TJ
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Discussion Starter · #12 ·
i found a great small enclosure build. this would fit darn near anywhere. 2018 Golf Sportwagen Simple Build - Page 2

Or Mr. Bateman has done a lot of work with 3" drivers and such. like maybe you cant fit a single 6.5 but you may be able to fit 2 3" under the seat.
Interesting read! I probably could fit a pair of 3"s, or 4"s, under the seat. I actually have some 4" coax's that were the initial occupants of my dash (4 x 6 with convertor bracket) before I cut a dash support and moved in the 5.25 pods. I'm sure they would need to be upgraded as I'm not sure how well they would do with midbass overall, but maybe they'll work for a bit. Christmas is going to put a delay on my system building 馃槖.

have you tried the over head pods yet?
Not yet. I didn't want to take my 5.25s out of the mix and have all of the mids coming from behind my head, so my initial plans were to buy the third amp (a little NVX VADM2, 150 x 2 RMS), test that on the 6.5" overhead speaker bar, keep if the imaging isn't too bad. I have a feeling, though, just from experiments with the sub crossover at 140 Hz, that I will probably get localization if those are bandpassed at 80 -> 200. But it would let me get some fill until I could figure out where to install.

My current plan of attack: upgrade sub box to dual 10"s, get my second sub, then third amp to run midbass.

what side and what's the bandwidth look like on this bad Larry
I don't quite follow....
 

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Discussion Starter · #13 ·
The fundamental tone is the main tone. The
timbre鈥 is what creates the 鈥渟ound鈥 of say a piano. When a piano key is pushed, a string is struck setting it into a complex motion. The whole string vibrates in one big up and down, and within that 鈥渨hole鈥 vibration smaller sections vibrate. Those are the harmonics and they give the timbre.

View attachment 316189
View attachment 316188

These harmonics are governed by mathematics and can be thought of as fractions. The same with a flute or French horn. The column of air behaves like a string except the air columns compress and stretch in those fractionally governed ways.

This is a little bit above my pay grade now but a subwoofers port can have these same 鈥渞esonances鈥 and have an effect on the sound. In winsid, when modeling an enclosure with a port, there鈥檚 a place that shows the 鈥1st鈥 resonance and in certain cases it can cause problems in the sound. It鈥檚 usually a moot point but just showing how the fundamental tone and it鈥檚 harmonics work in almost everything in the world, speaker cones included.
Oh wow! That does make a strange kind of sense. I'm working my way through Master Handbook of Acoustics but the harmonics section didn't make a lot of sense to me. So, essentially, the main part of the frequency spectrum that a lot of instruments play isn't being rendered in my system.
 
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Discussion Starter · #14 ·
I figured if I could find a front-of-vehicle solution for the midbass then I could just disconnect my 5.25s and use the 6.5s instead for a while, at least until I can get that third amp and go active 3-way.
 

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2004 Rav4 (2)JL900/5 MiniDsp 8x12(Dirac) LPG26NA GS25 Epique180-44 (2)Um12
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Interesting read! I probably could fit a pair of 3"s, or 4"s, under the seat. I actually have some 4" coax's that were the initial occupants of my dash (4 x 6 with convertor bracket) before I cut a dash support and moved in the 5.25 pods. I'm sure they would need to be upgraded as I'm not sure how well they would do with midbass overall, but maybe they'll work for a bit. Christmas is going to put a delay on my system building 馃槖.



Not yet. I didn't want to take my 5.25s out of the mix and have all of the mids coming from behind my head, so my initial plans were to buy the third amp (a little NVX VADM2, 150 x 2 RMS), test that on the 6.5" overhead speaker bar, keep if the imaging isn't too bad. I have a feeling, though, just from experiments with the sub crossover at 140 Hz, that I will probably get localization if those are bandpassed at 80 -> 200. But it would let me get some fill until I could figure out where to install.

My current plan of attack: upgrade sub box to dual 10"s, get my second sub, then third amp to run midbass.



I don't quite follow....
4 of these on each side might be shallow enough to fit under the seats and get decently loud and low. Definitely recommend testing the under seat location with one in a test enclosure.
 

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2004 Rav4 (2)JL900/5 MiniDsp 8x12(Dirac) LPG26NA GS25 Epique180-44 (2)Um12
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My bad

 

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1999 Jeep Wrangler TJ
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Discussion Starter · #17 ·
4 of these on each side might be shallow enough to fit under the seats and get decently loud and low. Definitely recommend testing the under seat location with one in a test enclosure.
Four 4" drivers under each seat?
 

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Four 4" drivers under each seat?
Yes, if you鈥檙e depth is very limited. Four 8ohm drivers will be 2 ohm and each time the number of drivers double you get 3db of efficiency added to the sensitivity. So four of those drivers will be in the 90鈥檚 sensitivity wise on each side. The concerns are the response will be limited to around 200hz or lower and under seat might not cure the null. Definitely a 3 way solution and you might still have a problem integrating the midrange and under seats through the crossover.
 

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Discussion Starter · #19 ·
Being a 2-door, the mechanisms under each seat are a little different.

Passenger side:

Automotive tire Hood Motor vehicle Bumper Rim


These seat folds forward, which is super convenient for access and measurements.

Driver's side:

Vehicle Automotive tire Hood Automotive lighting Automotive exhaust


The current home for my DSP and monoblock. I could move these under the rear tumble seat, which access would be fairly easy since it, well, tumbles.

About 9.75 inches wide, quite a big longer, 4" high between the floor pan and the adjustment bar, though once I get CLD and carpet down it'll shorten that a bit.
 

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Discussion Starter · #20 ·
Yes, if you鈥檙e depth is very limited. Four 8ohm drivers will be 2 ohm and each time the number of drivers double you get 3db of efficiency added to the sensitivity. So four of those drivers will be in the 90鈥檚 sensitivity wise on each side. The concerns are the response will be limited to around 200hz or lower and under seat might not cure the null. Definitely a 3 way solution and you might still have a problem integrating the midrange and under seats through the crossover.
Eek. So potentially a lot of work for no gain (pun).

I wonder if I should just focus on doing door panels, then. My boss (former pro installer) recommended I just cut the spot for the speaker, bondo to fill the gaps from the door panel's little dips, then run in basically IB. I'm just not sure how well this would work, or how much I'll have to get into deadening and bracing inside the door. It's totally hollow inside other than the small metal rods for the door latch and door lock. Seems like it could become another rabbit hole to fall into.
 
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