Help choosing sub

[Alien Mantis]

Originally Posted by sqcomp

I'm going to disagree with your statement on how smaller woofers tend to be more tight simply because they're smaller. I'd refer to the enclosure to make the woofer more accurate(tight) or being able to provide more low end extension(boominess). The enclosure will dictate the performance of the woofer.

I totally agree.

A 15" woofer in a sealed box can certainly play tight, musical bass.
The trade-off is "box size", and amp power required.

Remember, we all own Yarii.

I can't put a 2cf box in my Yaris HB. It just won't fit unless I wanna have the rear seat folded down all the time, which I do not.

Anyone who knows anything about subs knows the "enclosure" dictates performance. Box-tuning is everything.

I still stand behind my tens! I would rather run four tens, than two twelves, or two fifteens anyday.
Just my preference, of course.

[yarrr]

I like how the posts just get progressively bigger through this thread. I feel I should be writing a short novel here.

FWIW. I stood at the back of a yukon with the hatch open blasting 2 13" W7s. That's "my face feels like its gonna get ripped off" bass

[Damo]

Also, if you're listening to music that is more intricate or busy, such as orchestral or heavy metal stuff, it is often wise NOT to go too large a sub anyway, as the smaller subs tend to be cleaner and tighter in their performance. Even though a 10" (or dual 8's) may not have the LF extension of a 15" sub, its rarely needed anyway in most musical performances.

[Alien Mantis]

Originally Posted by Damo

Also, if you're listening to music that is more intricate or busy, such as orchestral or heavy metal stuff, it is often wise NOT to go too large a sub anyway, as the smaller subs tend to be cleaner and tighter in their performance. Even though a 10" (or dual 8's) may not have the LF extension of a 15" sub, its rarely needed anyway in most musical performances.

Very good point.
This has been my experience as well.

I said in an earlier post, if you optimize your system for RAP, it won't be optimized for ROCK. ( and vice versa )
And this is what I was trying to say about that.

I have always liked 10" woofers, because they are perfect for my kind of music.
If I listened to rap, I would probably run a pair of 12's in a ported box.
( for that loose, boomy bass )

8" woofers are nice too, but I would have to run two of them to get any kind of SPL out of them, which is why I decided on one Alpine Type-R 10" sub.
A pair of 8's would have been more money, and they would have required a larger box than one 10" sub requires.

"Car Audio" is like "Fine Art".
It's all up to a persons individual tastes.
Many directions you can go. Do whatever makes you happy.
That is what counts.

[Damo]

Sorry sqcomp, I must not have been clear with my previous post - I was basically agreeing with your arguments, not challenging them. The beauty and clarity of text on the internet, eh? :)

Regarding subwoofers though, LFE cannot be produced by an enclosure. The speaker either has the capacity to play the frequency, or it does not.

Certainly, the box can and will alter the response/performance at certain frequencies, but when I commented on larger subs and low frequency extension, I was referring to 'how far' down the Hz scale a sub could produce - not the boominess of the speaker.

Sorry for the confusion!

[Duckywitbigfeetz]

lol I Love how I unintentionally start arguments... hey guys here is a pic of what im comming from as you can see this is the reason why im going with a single subwoofer versus 2. I do listen to mostly rap but i make all my boxes custom and have so for years certian time sealed certian times ported depending on the sub really " in my experience some subs just do better in one type versus another" and im not opposed to building another if it doesnt come out right.

As for the clipping argument my general process is this ( im an electrical engineer so i have lots of cool testing tools)

1) set unit at max volume with single sine wave for no cilpping/ distortion
2) I have 3sixty so set this as well
3) amp then back down about 20-25%

**if all up to amp is not clipping then make sure there is a little room for varrying levels from differend sources i have very little problems

** i have also built a tiny little addition to my outputs which activales an led when/if ( doesnt happen often in my experience) the signal clips so then i can adjust with volume knob feature of 3sixty processor

This was more of an opinion question to all of you very smart guys on which one would match better with this amp.

[talnlnky]

Originally Posted by Duckywitbigfeetz

As for the clipping argument my general process is this ( im an electrical engineer so i have lots of cool testing tools)
[/IMG][/URL]

I have a buddy in the airforce who's job is to set up communication towers (from scratch) and repair electronics.... he's got access to some crazy stuff too. Oh yeah... he has to make sure the base is shielded from EMP blasts... so he has a giant EMP generator. Course... he then moved to germany.... and then I moved a state south, no longer have access to all his tools.

Wish I had an O-scope... that and a clamp meter and I think I would be happy.

[Alien Mantis]

Originally Posted by Duckywitbigfeetz

hey guys here is a pic of what im comming from as you can see this is the reason why im going with a single subwoofer versus 2. I do listen to mostly rap but i make all my boxes custom and have so for years

WoW.

Nice "showy" setup you got there.
( a little black carpet on that box goes a long ways. )


That sub setup you got there just KILLED ALL the space in your cargo area.

As much as I would love to have a pair of Type-R 12's in my Yaris, no way was I gonna give up that space back there.

You are going to have a hard time finding one sub that will equal those two bad boys back there.
Since you listen to RAP, you will definitely want a ported box.
And I don't think ANY single 10" will make you happy.
( maybe the JL W7, or a high-power ORION HCCA )

Although, it looks like your box is a sealed box, yeah?
If so, one sub in a ported box might surprise you, playing RAP beats.
I was really surprised at my 10" Type-R in a ported box.
It sounds nice with rock kick drums, but it really shines when I tried some BEAT DOMINATOR on it. The whole car was vibrating really good.
My box is definitely tuned for RAP beats, but it also sounds nice on rock music, which is why I decided to keep this setup.
If I put my Type-R in a sealed box, it would tighten it up some, but I know I would lose some SPL too. It's always a trade-off.

If you are looking to save space, try a single 10" W7 in a ported box.
That might be your solution.

[sqcomp]

...damn...

I wish I had a 360 and a clipping indicatior to do that with

I'm juuuust playing



....8 days until I GTFO of this cornhole of a country and 15 days until the project continues...

[talnlnky]

Originally Posted by sqcomp

...damn...

I wish I had a 360 and a clipping indicatior to do that with

I'm juuuust playing



....8 days until I GTFO of this cornhole of a country and 15 days until the project continues...

get your hands on an 0-scope for a day... it'll be more accurate... But even o-scopes aren't perfect... By the time you see some clipping, you've been clipping for awhile. Generally you find the clipping spot using the scope, then dial back a tiny bit. I would think the gains would be the absolute last thing you would dial in for an SQ car... I mean... set them close, but not until you had perfected everything else would you really spend time tweaking with the gains. I mean, everytime you add some boost on an eq you just have changed the volume at which you can turn your deck up to before clipping occurs.

[Duckywitbigfeetz]

**Alien Mantis
yea thats why im getting rid of the 2-12's had to go sealed and inveted to get volume necessary but built for a fb of 36Hz.

I dont mind giving up most of my trunk or all because im looking to put a small tv back there anyways possiably with tv on rails rising up. doing this more for quality probably gonna go ported with a 12 with a box tuned to about 32-36Hz. messing with bass box pro now trying to get volumes right.

Any ideas on what port diam would get good sound and minimize turbulance. i usually use 3" round but with my volumes now the length is only about 3 inches. any recomendations?

[sqcomp]

"O scopes aren't perfect...By the time you see some clipping, you've been clipping for awhile."

I suppose that's true if you've never used one on your equipment. I don't quite register the logic though. A scope is the best thing we can get to see if our equipment is dialed in. It's more accurate for this type of measurement than our ears. I submit that we can't hear 1% distortion caused by clipping whereas a scope would easily show you before you even hooked the speakers up.

In my situation, I see myself "gaining by ear" and then taking it to an electronics repair shop (unless Jim has a scope that I don't know about...which wouldn't suprise me) to have them give me some measurements. At that point I'll adjust the chain and then hit the auto EQ...take a reading on the scope, adjust the chain...hit the auto TA...take a reading on the scope, adjust the chain...and finally tweak manually, this includes not only the EQ but the crossover slopes (which I will have to do). One would be suprised what messing with crossover points and slopes can do for your soundstage!

Before that I will have spent a LOT of time with the speaker placements (especially the midranges and tweets). PLDs are a killer!

...as a matter of fact...

This is a GREAT idea! I should do a tutorial on level matching while I'm doing my system! Oooooh! Nice.

[talnlnky]

Originally Posted by sqcomp

"O scopes aren't perfect...By the time you see some clipping, you've been clipping for awhile."

I suppose that's true if you've never used one on your equipment. I don't quite register the logic though. A scope is the best thing we can get to see if our equipment is dialed in. It's more accurate for this type of measurement than our ears. I submit that we can't hear 1% distortion caused by clipping whereas a scope would easily show you before you even hooked the speakers up.

distortion and clipping don't translate perfectly... as in 100% clipping doesn't mean 100% distortion. By the time a Scope can detect clipping... you already have a few percents worth in a clipped signal.

[Duckywitbigfeetz]

that would be a great idea would love to know if my routine matches up with other people into sound quality.

*side note* need to move my tweeters but cant until I paint my interior i drilled holes, and also wanna add another set of 6.5 or 8 subs in front doors. (mebe not necessary second part)

[sqcomp]

why would you need to add another set of mids? Are you not receiving good bass extension?

I've got a step by step already made up for tuning with the EQ and speaker aiming...I'm saving that until I get the pictures behind it from my build.

I'l also bring a tutorial for what I did for level matching...as I have the whole process down.

[Duckywitbigfeetz]

hey sqcomp i got another question for you ( or anyone else who knows the answer). I have calculated the port length to be 11.65 for my tuning frequency. Now the question is that i would like to put the port in the corner of the box ie. using 2 sides of the box for 2 sides of the port. i know that for ports only using one side of the box there is a correction factor of 1/2 h on the length. Is this the same for a port using 2 sides.

[talnlnky]

Originally Posted by Duckywitbigfeetz

hey sqcomp i got another question for you ( or anyone else who knows the answer). I have calculated the port length to be 11.65 for my tuning frequency. Now the question is that i would like to put the port in the corner of the box ie. using 2 sides of the box for 2 sides of the port. i know that for ports only using one side of the box there is a correction factor of 1/2 h on the length. Is this the same for a port using 2 sides.

hehe... you're trying to get really specific and fined tuned. I have to admit, it's been awhile since i've been able to build boxes (shopless for amost 2 years now). I believe there is some very minore correction, but realistically, that correction will only change the tuning on a sub box by +/- 1hz.

The way I do it, is to figure where my port will be, so if its on the left side of the box, then goes to the back, then takes a 90degree turn alongside the back wall to the right. I take a straight edge, and draw exactly where my port walls will be. I then find the exact center of the port, and draw another line. When you are done, you should wind up with two L shaped marks on your box. the line that passes through the center of the port is the line I would use to do the measurements... (for you 11.65 inches long). I do remember that boxes that are designed off of wavelengths like transmission lines, every turn you do have to re-adjust for.... but wavelength based boxes often have a half dozen or more turns... which add up to a significant correction factor.

To sum up, I believe you are supposed to do some correction for every turn, but not sure, As for walls.... I don't think it matters for walls.

I would be more concerned with the displacement of the sub & internal bracing than I would be of the correction factor of a single turn.

[sqcomp]

...Am I missing something here?

Are you saying that an o-scope won't detect a clipped signal until it's...already clipped or distorting? Are you saying that by the time the scope shows a clipped signal, you've already got a few points of distortion?

A scope will show the wave as it happens. One can follow it (the display of the signal) into clipping if one so wishes by feeding the signal more Voltage.

How about this:

"The real heart of the issue is that every component has a noise floor below which it cannot pass a clean signal. Every component also has a maximum level above which it cannot pass a signal without severe distortion. In operation, it is critical to make sure the signal stays as high above the noise floor as possible without exceeding the maximum undistorted level. This is important no matter what the brand, price, or design the equipment may be. It should be acknowledged that an experienced technician can probably do a quick "tune it by ear" and get most systems pretty close to optimum, but it is just as true that to achieve 100% of a system’s dynamic performance, the use of test signals and at least basic test equipment is needed.

There are really only a couple things that are needed to do a professional job of level setting in an audio system. A good stable low distortion signal is the first thing required. I suggest you use a frequency of somewhere in the 500 Hz to 1 KHz range. A suitable signal would be what we call recorded at “all high bits” (AHB). This means that the signal outputs the highest voltage that would ever be encountered from an undistorted music source. There are numerous test CDs that contain suitable signals or you can burn your own from one of the numerous web sites that contain test signals.

The best way to monitor any electrical signal is to use an oscilloscope...Start with the head unit and while monitoring the output with whatever device you choose to use, advance the volume control until the component just starts to exhibit clipping. Since pure sine waves can sometimes damage speakers, I prefer to turn the power amps off or at least way down just to be safe. After the head unit is set, proceed to the next component in the system and set it right to the verge of clipping. This process is to be continued all the way through the system till you reach the last component that actually feeds the power amps.

There are a couple things that have to be mentioned that can complicate the process thus far described. First is a component that has input and output gain controls. With these components, start with the output control all the way or at least almost all the way down, and adjust the input control first. Then adjust the output only after the input is adjusted.

A second complication is if a previous component seems to be overdriving a downstream component. In such a case it could be necessary to go back to the previous component and reduce its gain enough to accommodate the downstream component.

The third complication is when there are multi-way electronic crossovers in the system. If such is the case make sure that you only monitor the output that is in the pass band that contains the test signal. To set the other bands (usually feeding woofers and tweeters), it is possible to use another test signal or you can set these additional bands to the same gain as the mid-band and you will have things very close, since the maximum voltage of the device will be the same for all outputs since it shares the same internal power supply."

The final adjustment is called Gain overlap. "Gain overlap is an intentional mismatch in the final gain adjustment done right at the power amp. This procedure allows for short term music peaks to be clipped and at the same time allowing the average level of signal to be increased. The net result is a large, noticeable increase in how loud the system will play.

Much testing of skilled listeners has shown that the added distortion of a 10 dB gain overlap is extremely difficult to hear. It just so happens that the real bonus of a 10 dB gain overlap is that the system will play at a level that is perceived by listeners to be fully twice as loud. Of course you can choose the amount of overlap you care to incorporate, but less overlap reduces the usable loudness, and more overlap leads to distortion (that is) audible.

The gain overlap is achieved by doing the very last amp gain adjustment with a test signal that is reduced in level by the amount that you want to have the gain overlapped. As such, a 10 dB overlap would be done by adjusting the amp gains with a test signal that was 10 dB less than the "O" bit signal that is used for the rest of the system components." -- R.C. 2004

Ducky -- Taln has the calculators to help you with the port issues you're asking about. Taln and I are "Geeking" right now about wording on the level matching (see also hijacking your thread)...Sorry bout that.