Auto Tuba for Accord Coupe

[MA043HA]

This horn subwoofer building thing is addictive! Just finished an amazing THTLP flat pack for the living room and before even cleaning up the garage/workshop I want to build an auto tuba this time cutting my own panels.

Just bought a 2014 Accord Coupe (6 speed manual). It's the LX-S trim - the base model - and the 5 speaker sound system leaves something to be desired especially in the bass. So...

Bought the plans today along with the panel jig plans. With the smallish coupe trunk (and I do like to use it some) I'm thinking a standard autotuba but not the very smallest - maybe 16" wide with the Dayton 10" driver.

Unless there's a cutsheet for 5x5 BB I will probably call around to the local lumber yards and see who has it and will cut it into ??? 20x60 panels? Those would probably fit in my buggy with the back seat down.

Advice as I get started?

[Tom Smit]

Ooooo, that's gonna crush!

If you are going to go 16" wide, how about having the panels cut to 16 1/2". This way you can trim to width at home, and the remaining width of 27" will give you more options.

[MA043HA]

Will I need more than 1 5'x5' sheet?

[Tom Smit]

Download and use Cutlist. (Give him a donation for such a wonderful program). Input your panels and sides on the LH panel, and input your supply sheet(s) on the RH panel, and the program will come up with possibilities; I usually stop it after 10. This will help decide the number of supply sheets.

[jimbo7]

I think I used a 4x8 sheet and 2x4 sheet of auraco. Plenty of leftover, but that's what cutlist came up with

[J_Dunavin]

What amp and or external crossover are going with? Are you keeping the factory system or ripping it out?

[MA043HA]

What amp and or external crossover are going with? Are you keeping the factory system or ripping it out?

Not sure what to do yet. On my old 2003 accord coupe I took it to Rich's Car Tunes in Watertown and they replaced the factory speakers with JL Audio all around. Left the factory HU driving them and no sub. That was a nice bump in sound quality as I recall but now I'd like to go further. I started reading on some of the car audio and Accord/Honda forums and watching YouTube. I've pretty much decided to keep the stock HU because if its integration with so many other functions. I could come up with the funds to do this in a big way or cheaply or somewhere in between.

Install sub, crossover, amp, line level converter myself perhaps tapping into rear speaker wires. no sound deadening or factory speaker replacement.

Have pro install sub, crossover, amp etc and additional work as budget decision allows:
sound deadening at various levels of thoroughness - doors, floor, roof
factory speaker replacement - front only vs. all.
amps to drive replacement speakers vs driven from stock HU
DSP to control and tune/unite this specific component combination for this specific car

Questions:

How much control can I have over this system while driving? I'd like to both have it tuned for preset optimization at various ambient sound levels (speeds) and have manual control at least over the sub level if not crossover and phase.

More basic - why is the auto tuba the best sub for a car closed off in the trunk as it will be (doesn't that muffle it?) versus treating the trunk as a back space for an IB sub?

With Rich's Car Tunes essentially defunkt where to go in the Boston area for great car audio?

[J_Dunavin]

There are a lot of different ways to go, with subwoofers. IB is just one of many options. "Usually" at least in my experience, IB set ups, require a lot of work to seal off the trunk and need a lot of cone area, if you want to go really loud, but they do sound nice.

The AT is really cool because you don't have to have a lot of power, and you don't need a huge woofer either. I only have the 8" mcm woofer and it rocks!

At a minimum you will want an amp, or external crossover, that has a high pass, or subsonic filter as some marketing calls it, to cut off the lowest freq. else your auto tuba will go POOF. I forgot if the plans actually call out a freq on that... (I have mine set to 30hz, 24db). During set up you will also want to measure the voltage, so as to not overpower it.

With whatever set up you go with, you should be able to do sub level control, pretty easily.

[Radian]

Questions:

How much control can I have over this system while driving? I'd like to both have it tuned for preset optimization at various ambient sound levels (speeds) and have manual control at least over the sub level if not crossover and phase.

More basic - why is the auto tuba the best sub for a car closed off in the trunk as it will be (doesn't that muffle it?) versus treating the trunk as a back space for an IB sub?

1. While having a knob up front to tweak the sub is nice, I've found over the years that finding the balance point between "too much" and "not enough" bass ends up being much more convenient. My Accord with the Boss amp has a knob up front. The GF's car with the NVX amp does not. We hardly mess with either. More often than not I accidentally bump the knob under my seat while reaching for stuff and mute the sub entirely.

2. Best sub? The back seat will muffle 80Hz and above to a varying degree. Depends and the build quality of the car and where your acoustic crossover point is. I can fold the back seat (and often do) on my Accord and pick up a little extra dB out of it. Nothing critical per say, but still worth considering. In contrast, the rear seats in the GF's car are paper thin with no difference sound-wise up or down.

[MA043HA]

"I've found over the years that finding the balance point between "too much" and "not enough" bass ends up being much more convenient."

I read this in context over and over but don't get it. Taking just your car as an example where you DO have a sub level control knob under the seat but don't use it are you saying that finding the balance point between too much and not enough bass ends up being "convenient" (i.e. easy to do)? If so how if you don't adjust the level? Perhaps you're saying that finding that balance point ends up being irrelevant? unimportant? ignored in favor of other things to focus on such as the music itself and not the "sound"?

Please elaborate.

Maybe related to your example, I find with a lot of these projects I get energized for DOING it and lose interest when it comes to USING it as I move on to another project.

[Radian]

What I meant to say is that having the knob up front is nice, but it's also not the end of the world if an amp doesn't happen to have one.

When you get the crossover dialed-in correctly, you're much less likely to mess with the subwoofer level. Tweaking the EQ afterwards will yield better results.

...and for the record, it IS important, and not to be ignored. The subwoofer will be, after all, better than 70% of the sound energy reaching your body.

Maybe related to your example, I find with a lot of these projects I get energized for DOING it and lose interest when it comes to USING it as I move on to another project.

That's about normal. At least you realize it, but also try to improve upon that. They're two completely different worlds.

[MA043HA]

When you get the crossover dialed-in correctly, you're much less likely to mess with the subwoofer level. Tweaking the EQ afterwards will yield better results.

Thanks for the clarification Radian. So are you suggesting having some kind of EQ at your fingertips while driving? I could see myself often using that to compensate for recording differences.

This line of inquiry is of course not directly part of the "build" but essential at some point for a novice auto sound integrator like myself.

Back on the actual build topic, I bought 2 5x5 sheets of BB yesterday and had the lumber yard cut them into three panels each - 2 18" wide and the remaining 24".

[Tom Smit]

When you get the crossover dialed-in correctly, you're much less likely to mess with the subwoofer level. Tweaking the EQ afterwards will yield better results.

Thanks for the clarification Radian. So are you suggesting having some kind of EQ at your fingertips while driving? I could see myself often using that to compensate for recording differences.

I have an Alpine M500 (no remote, no subsonic filter). After I got everything adjusted, I only use the "bass" adjustment on the factory radio for EQ. Typically, it's at half-way position, but just a bump up yields the extra bass that I'm looking for.

[NukePooch]

For me, I'm glad I installed a sub level knob. My AT is easily capable of outrunning the door speakers. It's nice to be able to get the windshield vibrating when I want, but then turn it down when i want it balanced.
I've got a cheap closeout Sony mono sub amp. My 'bass control' is a simple level control inserted in the signal RCA's between the head unit and amp. I removed the case and put it through a dash trim panel. Easy, clean, and unobtrusive.

http://www.sonicelectronix.com/item_405 ... -XBRC.html

[MA043HA]

Page 4 of the plans says "Using a circular saw and sled cut out of the first side the driver access hole as shown in the diagram. Make sure you cut on the inside of the lines. Screw the sled to the side so it can’t slip. Cut not quite to the end of each line, finishing off the cut with a jigsaw. Support the side on a couple of guideboards, so that you don’t saw through the workbench. "

As a woodworking noob I don't immediately get this. Is there some way in which the circular saw does a plunge into the wood? Should an initial slot be cut with the jigsaw for the circular saw blade to go into?