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Determining factors on sub purchase

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26 replies to this topic

#1 of 27 OFFLINE   brentl



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Posted November 03 2003 - 12:31 AM

I guess the biggest thing I wonder about when it comes to car audio is

"Is linear excursion the best way to make a lot of bass?" and "What are the downfalls of a large Xmas"

I'm sure it's easy to run 2-3-4 subs in a car and use the entire trunk, but can you get a single sub sealed enclosure that both pounds, and is musical??

Do you give up some musicality for shear output?

I'll tell you why I ask. I'm looking(in the spring) to do a pretty major upgrade to my car audio system in my Civic and WILL NOT use my ENTIRE trunk for an enclosure.


#2 of 27 OFFLINE   Angelo_Petralba


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Posted November 03 2003 - 11:35 AM

If you got a trunk....and still want to utilize MOST of the trunk, I would venture into building/fabricating an IB for the subwoofer portion of your system.

The Pros:

Less room taken
Less power needed

Sometimes gets difficult to fabricate..and if the car is leased, you might have to remove the 'extra' sounddeadener or foam that will be used to seal the front baffle from the back.

May need to be EQed a bit. (But EQ's are good to have)

Some candidates for a good IB set-up in car would be

Image Dynamics ID MAX
Elemental Designs "O" series
just to name a few.

I hope this helps


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#3 of 27 OFFLINE   Sean^M


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Posted November 04 2003 - 09:22 AM

surface area and Xmax determine the SPL, yeah given you have ideal power for the subs in question.
If you want a single sub that will give you crazy SPL in a reasonable box, look at the JL Audio 13.5W7 in a slot-ported enclosure, and use a JL 1000/1 to drive it.
Be sure you have an alternator that can handle the load.

#4 of 27 OFFLINE   scott>sau


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Posted November 04 2003 - 05:19 PM

A sub should not really be musical. A good sub in car audio, or home theater should be articulate (clear-not muddy) and that comes from clean, adequate power. A good sub should sound deep and solid. The enclosure is the trick to that. Many people (IASCA and USAC) swear by sealed enclosures. They take up less space and sound make a woofer sound tighter. Of course Wayne Harris of Rockford would ask me if I was drinking if he heard me tell you this. He just wants his 180dBs!

#5 of 27 OFFLINE   Sean^M


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Posted November 05 2003 - 10:29 AM

he works for Rockford. nuff said. heh
ten years ago I might have been impressed.. now, they just produce mass-marketed junk on par with audiobahn.
They've fallen a long way, and his distain for a good sealed box should indicate that.
Sealed will take more power, and while those looking purely for SPL will go for a 6th or 8th order bandpass box (if they can find someone to build it for them) people interested in SQ will avoid a bandpass box like a venerial disease.
a well made ported box, tuned around 34Hz can sound pretty good, too, and will save money in the need for a huge amp to drive an otherwise sealed box, but remember, not all subs work in all boxes.
if ya want to know the type of ideal box for your sub, figure out it's EBP (Fs/Qes) below 50 is sealed, 50-90 is flexible, and over 90 is ported.

#6 of 27 OFFLINE   scott>sau


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Posted November 05 2003 - 12:37 PM

Rockford moving into Crutchfield was a bad marketing move in my humble opinion. When I worked with Wayne in '95 the Tempe, AZ plant was doing the best they ever where. You would have to prove to me and this thread a valid source that the Michigan RAD speaker plant was spitting out shit like Audiobahn.It's a rivalry. There will always be a team Rockford, team PPI, team Orion, team Xtant, team MTX, and teams from outside the Phoenix big five. And there will always be those who hate one brand over another subjectively.
I agree, sealed enclosures take a lot more power to bump than a 5th order, etc. I always wanted to put a M&K (www.mkprofessional.com) sub in my car and see what it could do for my ego. Dual 12's in a push-pull sealed enclosure. Got Bass!? Posted Image

#7 of 27 OFFLINE   brentl



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Posted November 06 2003 - 01:39 AM

You guys are killin mePosted Image

So I guess you guys equate Autobahn of today with Crunch from 10-12 years ago?

Couple idea;

Shiva ..... 2cuft sealed ...... 200 watts RMS crossed @ 40hz

I also wonder whather a good sub should be both musical AND articulate? If I was just looking for something to shake my ass I'd just get a couple buttkickers.

I'd like accurate bass .... a 30Hz note to sound, and to a lesser extent feel like a 30 hz note.

Does anybody know where on the web I can figure out the tranfer function of my Civic so I can design my box correctly??


#8 of 27 OFFLINE   Sean^M


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Posted November 06 2003 - 03:48 AM

ok lets see if I can do this without forgetting anyone.

I used to be a hardcore Orion and PPI fan, owner, and dealer/installer. I respected RF equally in that class, I just didn't sell their stuff, as the shop across town did instead. That was back around 92, not far off from your mention of 95. Things have changed though. Much of the above mentioned companies are no longer in Tempe, but the Philippines and HK now. When the companies were bought out by overseas conglomerates the quality dove right into the ground. DEI is another good example of this, with practically all of the car alarm mfgs now owned by the same parent company. Compustar being a rare exception.

RF's current line of amps and subs just aren't that impressive. They aren't trash like Sony, but they aren't the spectacular pieces of art they once were.
PPI and Orion have gone the same way anymore, sadly. I still miss those old Art series PPI amps, and still have my old early 90s Orion HCCA and SX amps.

As for the push-pull isobaric design, I've built these before, and you need to remember that while you'll gain the +3dB in efficiency over a single, sealed box sub because the subs are doing less work to move the same mass of air, and you eliminate any non-linearity issues since both subs move in identical paths, you still lose 3dB that you'd otherwise gain by having the second sub in it's own sealed enclosure.
End result, there's no gain to using an isobaric enclosure compared to sealed. It doesn't gain you anything over a sealed box in SPL. All you do actually gain, is space.

Audiobahn is total crap (this is all my opinion of course)
they get high sales because they set high "minimum" sales quotas for their dealers in order to maintain a license to sell their products, which means we as consumers get it shoveled down our throats. They chrome everything to make it look pretty, and like other similar companies (MA Audio) they try to use huge, heavy magnet structures to look more impressive on speakers (while in reality, at best, overdamping the drivers). The products perform "ok" at best, and poorly at worst. They have poor reliability, and much as their prices imply, are cheap.

Adire's Shiva subs are excellent on the other hand. You'd be happy with one or two of those if that's what you choose to go with. Good company, well made products.

As for the Civic, we don't get many foreign cars in this part of Michigan, so I haven't needed to find those specs recently for a newer one.

Sorry if I came across a bit bluntly there.. I hate to see people spend good money on bad products, and regret it later. We've all been there at some point. I've never been good at sounding nice and polite.. so I just say what's on my mind, and hope people can sort that out and not get offended, or take any of it personally. Posted Image
hope some of this helps.

#9 of 27 OFFLINE   scott>sau


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Posted November 06 2003 - 04:51 AM

Audiobahn is total crap (this is all my opinion of course)
That is hilarious! I mean it man, not being facetious, it was funny.
My feelings on Rockford Corp. is that bad management has infested it from the beginning. This isn't slander, just an obsevation. Jim Strickland is a good engineer and practically saved Rock Fosgate division and Wayne Harris helped in their marketing of signal processors with his Symmetry EXP gig. I was just in Tempe 2 weeks ago for a family funeral and visited the plant. They still "assemble" amps and signal processor's (crossovers, etc.) there by hand. The surface mount division is still running and Hafler home amps were still being assembled there. All there wire (RCA's ,etc.)comes from overseas. As far as the look of the RF heat sinks, they look more like spaceships than amps. Long live my punch 45s, punch 75's, punch 150's and my power 1000. They started to nosedive the design with the DSM series. Two GOOD things Rockford has left in their recipe is a strong power supply, esp. the power series and the trans-nova secret thanks to Mr. Strickland. As far as Rockford Acoustic Design in MI making their speakers there still, or overseas, I dunno. The moral of the story is, I was once a die-hard Iasca Rockford sponsored fan. But when I worked there I paid nothing for the equipment. Now my eyes have been opened and I know there are many more brands out there.

#10 of 27 OFFLINE   scott>sau


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Posted November 06 2003 - 05:40 AM

"you don't gain anything in SPL by adding that clamshelled second sub.
In other words, there's no real reason to use an isobaric enclosure of that sort. It doesn't gain you anything over a single 12" and you'd get more out of just having the two subs in their own sealed boxes. All you do actually gain, is space." Negative info here. Especially with home theater. See this site: http://www.mkprofess...om/mps5410.html
Two drivers always have more output than one. A push-pull sealed, (not isobaric) has more ouput than a sealed enclosure.

#11 of 27 OFFLINE   Justin_Terpstra



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Posted November 06 2003 - 11:22 PM

I have a 2001 Civic Coupe EX. Great car.

Heres what I did:
My homepage

This is where I got all my information ... and probably the best place for you to go. Loads of information. Go into the ICE forums (in car entertainment), I post under Regular_Joe.
2001 and up Civic website

Good luck.

#12 of 27 OFFLINE   Sean^M


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Posted November 07 2003 - 03:52 AM

actually what I was trying to say was that you won't gain anything with isobaric, over a straight sealed box aside from saving space.

#13 of 27 OFFLINE   brentl



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Posted November 07 2003 - 05:52 AM

"I still miss those old Art series PPI amps" You can't go wrong with ANY product that's pink and whitePosted Image

I guess I'm happy to say Iw as never a fan of RF stuff!!

I guess the biggest reason I'm seriously considering Adire audio is because they are a "known" quantity and quality.

I think for fun I'll pull my subwoofer out of my THX certified home sub. According to the web it's got more than an 11mm Xmas. Only problem is that it's 8ohm!.

Justin, I love spending time there. I just find many of the cars WAY over done. I've only seen a few I've liked because I'm pretty picky on how clean the car looks.

It's almost funny how much of a revolt Civic lovers are having towards "altezza style" lights. The y were all the rage a couple of years ago.

Don't like my tails, and I'd love to make my fronts true HD, but I haven't found anything nice enough.

#14 of 27 OFFLINE   Robert_J


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Posted November 07 2003 - 06:25 AM

The supply of Shivas is very low right now. There are some alternatives in this thread.


#15 of 27 OFFLINE   Scott L

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Posted November 07 2003 - 07:35 AM

I opted for an ED 12a powered by a Hifonics Brutus BX1000D. That's 1000 watts at 1 ohm, or so it says. Best part is great bass at under $600.

#16 of 27 Guest_Chris*Liberti_*

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Posted November 07 2003 - 10:22 AM

Also another thing with car audio is that below the transfer point (the point at which SPL is highest from a .707 Qsc enclosure) there is a 12 db/octave boost called cabin gain. Since a sealed box rolls off at 12db/octave and this is usually in the high 40 to low 50 Hz range (same as a lot of cars transfer point) a sealed sub will go lower in a car (a lot go to 10 Hz in car). A great sub for car use is the E12A by elemental designs. It hit 129 db by itself in a small (.68 cuft) enclosure in a vette. It also went to 9Hz flat in car and only costs $300

#17 of 27 OFFLINE   Sean^M


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Posted November 08 2003 - 02:30 PM

it'd be interesting to see how a sub gets to 9Hz flat in a car, since no analog source will go that low, and no digital source I'm aware of will either. CDs have a brick wall filter at 20Hz, and 20KHz, to avoid harmonics, and the "breaking glass" distortion caused below, and above those points respectively according to the Sony-Philips specs for CD-A.
The only way you'd hit that low, flat, is due to harmonics or coloration in the system.
Anyway, yeah a sealed box is always nice, it just takes a lot more power to get it to hit as hard compared to a good ported enclosure, which generally means more money.

#18 of 27 Guest_Chris*Liberti_*

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Posted November 12 2003 - 12:13 PM

It was tested using test tones from a computer program direct. Also CD can go below 20Hz. I have a few that have some activity in the 16 Hz range (organ music). Also some DVD's go low, Apocalypse now goes below 20 Hz in a few scenes.

#19 of 27 OFFLINE   Andrew S-

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Posted November 12 2003 - 02:23 PM

xmax will help you a lot in sealed enclosures but wont do much for you in a ported enclosure.

ported what really matters is power handling, Sd, and BL

look into elemental designs for your subs. they are awesome sound quality subs that get nice and loud if installed correctly. i would go ported tuned around 30hz depending on the box size you use.

#20 of 27 OFFLINE   brentl



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Posted November 13 2003 - 04:36 AM

An Eric Kunzel album put out by Telarc called "The Great Fantasy Adventure Album" has notes into the single digits!