BRCLS

how much do you think a audio shop would charge me to make a box for one l7 8 inch?

and also how much would they charge me to install the sub and a amp?

KyleWatson

Sealed, $150 or less.... assuming you want it square and carpeted. Ported, could be quite a bit, $250 roughly.... Standard amp with 8 gauge is about $50 around here, you may need some adapters on top of normal cables, all at you expense.... Prices vary by region, so just use this as an estimate....

Nicky Pass

Build the box yourself....a box for an 8" would cost you $20 in meterial.

BRCLS

50 bucks for install!!
that sounds good to me.


I just called 1 place he said he would charge me 260 for: box(carpeted), amp wiring kit, and install of it all.

BRCLS

building it my self would save me alot but, ive never done it.
I dont have a skill sawto cut it.
How do you figure the right demensions.

Titand19

VOLUME=Length x Width x Height

You would need a table saw to cut the MDF, not everyone has one of those just lying around. Not every audio shop has one either.

wakeboardfusion

u could just buy it off e bay

pimpscls

is ported better wit l7's how much would be for a ported box for 2 12 inch l7's

wakeboardfusion

just buy the ports urself and cut the hole and put them in

proaudio22

That's not all there is to it. Many people make the mistake of making boxes in cubes or close to it. Big nono.

Buying a circular port and cutting into a sealed box is retarded. For one, the ported box should be larger. The other this is that for this kind of application, circular ports really suck. There is too much air being moved too close to the listener - they make too much noise. Slot ported is the way to go.

Titand19

proaudio22, PM me with some shit I need to Know.

KyleWatson

First of all, it's (Length x Width x Height)/1728..... for volume...

Second, L7's, with round have absolutely no audible difference in the trunk of a car if done correctly. The usual port whistle that you hear can be eliminated by smoothing out the sharp edges... i.e. use a router to round the edges on the port.

I can agree that a slot port can sound SLIGHTLY different than a typical round port, but hearing the difference in a trunk is down right impossible (it mainly has to deal with the rough edges). To top that off, keep in mind home subs, rarely will you see a slot port..... All that matters is that the volume of the enclosure (minus the port volume), works with the volume of the port, and there is a smooth transition between the two..... Build whatever is easier for you, or works better for you application, just like they will do with home subs.....

We built boxes with Round Ports for L7's that were to the exact specs given by KICKER, and they sounded no different side-by-side the slot ported design...

KyleWatson

How else would you suggest building a box?

I realize that there are a few exceptions to the rule, but a rectangle box at 2 cubes, will sound the same as a square box at 2 cubes, with all other variable equal......

BRCLS

what is 2 cubes?

here is a quote from crutchfield installation guide:
"one of the worst acoustic shape for a speaker"
there talking about a cube shaped box.

here is there rule of thumb: "make shure no internal demension measures more than three times that of any other. but dont make them to close cause youll have a cube."

KyleWatson

2 Cubes, is short for 2 cubic feet.

Do you know the reason that they say that?

I know where it came from, and its out of context, and doesn't eliminate any variables.... All of that theory is in a book called, The Loudspeaker Cookbook. The best design for a speaker is a Sphere. It ranks a square box last. A few of my friends at work and I, have done a lot of blind testing with sub boxes, lincluding a rectangle vs. a square, and we could not hear the difference between the two using the same amp, the same sub, same car, exact same size airspace, and same settings.

Build the box to fit the application, and more importantly the sub, don't worry about having one side 3 times longer than another, or having them too close, because we weren't able to hear a difference in a car, regardless of whether or not a machine can measure it. I will give you this though, there maybe a speaker out there that can prove me wong, but the two different subs we did this with did not yeild a difference in performance, I would however like to see a sub that is that picky.....

BRCLS

so what is most important is the right amount of cubic feet and that its sealed good.

wich is best min cubic feet or max cubic feet, or in the middle?

KyleWatson

I personally think that it depends on the woofer, and the sound that you're going for. I'd call the manufacterer, and ask for a tech, and their recommendation....

proaudio22

The key word is correctly. Most people don't know what the fock causes the noise. Some of it might come from the sharp edges, but any decent port would already have a flared piece that attaches to the ends. The problem is using too small of a port. Many people get the 2" el cheapo special. 3" is the smallest, 4" is a good size. It's not just about volume. Slot ports are hard to fock up even if you don't round the edges unless you just make it the wrong size.

That is utter bullshit. Rephrase that to say all the home subs at Circuit City. In addition to that, most home subs don't move quite as much air either. I design home theaters - I should know. Half of the time tho, I use professional gear, stuff designed for real theaters. Most professional subs are slot ported simply b/c it makes less noise. It's not very practical to have 6" circles in the baffle.

You said it yourself - "all variables equal" - well they aren't equal. It's all about waves, cancellations, and resonance. A cube box has 5 of the same length surfaces, and could make some nasty refections inside. In reality, most of the "cube" boxes you see are not actually cubes. Most home theater type subs are either A) too cheap to matter or B) actually diff shapes inside (there are electronics in most of them, and I know of at least two manufacturers that have odd shapes inside to break up the eveness). 2 cubes is not 2 cubes. Change the angle of one surface (could even be the baffle as then the reflected waves change their angle). Stuff all the polyfill that you want to - if a wave of low enough freq and high enough aplitude gets going - no poly shit is gonna stop it.

Yes! Sealed good is of very high importance, esp in a ported box lol. The best choice of cubic ft and tuning freq depends on your car and your taste of music. Really you ought to so a pink noise sweet of your car to find out how linear or non linear it is. You might tune you box to 40hz and have a hot spot there and end up with a one note wonder trunk.

Titand19 - watcha need to know?

KyleWatson

"The key word is correctly. Most people don't know what the fock causes the noise. Some of it might come from the sharp edges, but any decent port would already have a flared piece that attaches to the ends. The problem is using too small of a port. Many people get the 2" el cheapo special. 3" is the smallest, 4" is a good size. It's not just about volume. Slot ports are hard to fock up even if you don't round the edges unless you just make it the wrong size."

So.... You agree....

"That is utter bullshit. Rephrase that to say all the home subs at Circuit City. In addition to that, most home subs don't move quite as much air either. I design home theaters - I should know. Half of the time tho, I use professional gear, stuff designed for real theaters. Most professional subs are slot ported simply b/c it makes less noise. It's not very practical to have 6" circles in the baffle."

The fact of the matter is that most home subs are not slot ported, many are, but not most are not. I should have said most, you're right in that.

To even try to equate me to Circuit City, and yourself to highend hometheatre is absolutely rediculous. I work at, and have been trained at, the most award winning audio and video dealer in the country. We have one of the best Theatres in the world, designed by Theo Kalomirakis (you may not know who he is, I"ll understand). We deal with companies such as Sumiko, and brands such as Krell on a daily basis. We design and build cars that have been in the IASCA world finals. Not that any of this matters, but I really doubt that your resume will compare to mine.

"You said it yourself - "all variables equal" - well they aren't equal. It's all about waves, cancellations, and resonance. A cube box has 5 of the same length surfaces, and could make some nasty refections inside. In reality, most of the "cube" boxes you see are not actually cubes. Most home theater type subs are either A) too cheap to matter or B) actually diff shapes inside (there are electronics in most of them, and I know of at least two manufacturers that have odd shapes inside to break up the eveness). 2 cubes is not 2 cubes. Change the angle of one surface (could even be the baffle as then the reflected waves change their angle). Stuff all the polyfill that you want to - if a wave of low enough freq and high enough aplitude gets going - no poly shit is gonna stop it. "

The point of the tests were to isolate the variables associated only with the box design, in order to hear a difference in a real world application. If we did make sure that all variables associated with the boxes were the same, THERE WOULD BE NO TEST. EVERTHING WOULD SOUND THE SAME!!!!!

This isn't a pissing contest.... I'm not here to prove you wrong, although it hasn't been too hard. I could keep going about many of your statements, including "home subs move less air than car subs," but I won't.... If you didn't try to come off as an arrogant know it all, it may be easier to give you the benefit of the doubt... Try to come off a little softer next time, or at the very least, make sure you know what you're talking about.

RR32CLS

you want a cookie...

proaudio22

Yea, I guess but my recommendation is still slot ported for those that don’t understand all this other junk. It’s easy for them to calculate the needed volume of the port and design it into an enclosure.

I would say only half of the home theater subs are traditionally ported. The other half are slot ported or something else (sealed, etc).

1. I do not work on cars. I simply learned enough about it to create myself a nice system. My buddy is the one that owns the car stereo shop, not I. Too many dumb people asking dumb questions for me. Mad props to RR32CLS for dealing with it.
2. Where did I equate myself to high end home theater and you to Circuit City? I simply said that to make your statement about all home audio subs being traditionally ported you would have to change that to all home audio subs at Circuit City. The fact of the matter is that I do not really deal with home audio. I’m a professional A/V contractor. I don’t fiddle with any of the silly audiophile shit. You can tout your Krell all you want, I’d rather have a nice rack of QSC. I really should change my earlier statement that I design home theaters. I only design/install home theater systems. I know exactly who Theo Kalomirakis is. Architects like himself (not saying as good as he is, nor worse) design the rooms, we install the systems. Out goal is to create systems that mirror a true theater. We don’t worry ourselves so much with audiophile sound (not to say that it isn’t important as we use top gear) as with function. I’ve helped design/install system for theaters up to 300 people and used projectors up to the Barco DP30. I’m sure for what I do, my resume kicks your resume’s ass. Home “theaters” are only part of our work. We install systems for live venues, churches, background systems, etc. We work with companies such as EAW, JBL-Pro, QSC, AMX/Crestron, Barco, Belden, etc.

Maybe YOU can’t hear this difference in a car trunk. So what, w/e. Get a copy of Smaart Live and play with it.

My comment about moving more air is based on the average over time. Most car subs get pounded to the max with rap beats with constant, almost sine wave notes played on them. It’s much easier to hear the port noise like this than on the rumble of thunder in a theater.

I’m not a know it all. I am an Electro-Acoustics student and A/V contractor. We can have a pissing contest if you want, I prob consumed more liquids that you tonight anyway. When ya gonna take delivery of your cookie? I’d sent it to ya with a $30,000 power cord so you can woo over how it makes a difference in the sound.

KyleWatson

You're still talking about something that you haven't even tried... We can play a copy of whatever you want with those too boxes including Diana Krall, IASCA competition and setup CD's.... I think someone even used the DVD player to play the Trans-Siberian Orchestra. We take audio very seriously, and I can't believe that you have to requalify every statement that you've made, and still have no experience designing enclosures. Sure, you can plug them in and run the cable, but you've never dealt with building the enclosure. You make a rediculous statement, "home subs move less air than car subs," then have to add later, I mean over time, car subs move more air over the life of the sub. WHY DOES IT MATTER WHICH SUB MOVES MORE AIR OVER TIME? That statement doesn't even apply to the topic, let alone have any sort of real ration application to sound quality. I'll take that cookie, with the power cord... just let me know when you're done plugging in all that highend gear you work with on a daily basis.....

proaudio22

Where did I say I haven't built enclosures? W/e man...do you know what a folded horn cabinet is? My boss and I designed the larger cabinets that we use now. The woodwork alone weighs over 200lbs. We ran driver simulations, box simulations, etc to get them just right. Building a car sub enclosure is small beans, esp for you guys who think you can make w/e shape you want and it doesn't make a diff. WHATEVER WHO CARES. If your customers are happy, great. Are you familier with Smaart Live? Do you know what a TEF anaylsis is? Prob not. I'm sure you would be able to explain the principal of a Unity Horn as well to me? What about a Hyperbolois Reflective Wavesource? How about how a cardiod sub works with three drivers to create a narrow as 120 degrees of directable bandwith down to 30hz? Can you explain even a general line array theory to me? Can you explain the difference between phase and polarity - or do you think a reversal in polarity is the same as a 180 degree phase change? Can you explain how a box can have drivers facing perpendicular to the listener but yet direct 80% of the output toward the listener? I bet you can't. I also bet you'd argue that signal cables are directional.

What I said about car subs moving more air over time does apply to this topic. I changed this from just car subs move more air, just as you changed things you said to make them correct. It applies b/c in a car it's easier to hear port noise when a subwoofer is constantly pounding 30/40/50Hz notes out. On in improperly designed circular port, the noise would be audible. There would be no such noise audible from a slot port.

Again, it is YOU! who is assosiating me with high end audio gear. Where the hell are you getting this from? Yes, we may use a Lexicon processor in home theater but we don't juggle around exotic Neumann mics every day either. I don't see your point here.