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.

[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 Alien Mantis

You contradict what many manufacturers are recommending to consumers.

I read plenty of information from the likes of Alpine, JL, Pioneer, etc... that claim you are just flat out WRONG.

You CAN underpower a sub.
Whether or not it will damage it... I don't know.

A sub is designed for a certain "power-range".
If you give it too much power, it can smoke it.
If you give it too little power, you won't have any performance/response out of it.
High power subs NEED power to push them, and keep them tight, especially at higher volumes.
If we could use a 50watt amp on our pair of Alpine Type-X 12" subs, EVERYONE would be doing it!
Who wants to spend $400 on a 1,500watt RMS amp if I can push my sub setup with 50watts ?!?!?

Subs like the JL W7 and Alpine Type-X REQUIRE lots of power to push them, and keep the response clean and tight, especially at higher volume levels. Nobody buys a JL W7 to play SOFTLY.
People spend big bucks on this stuff because they want people to hear them coming down the street.
PERIOD.

My Alpine Type-R 10" sub has a recommended power range of 200-500watts RMS. And 200 watts would be the bare MINIMUM. It probably sounds pretty weak with only 200watts trying to push it.
( and most likely, not as tight sounding, either )

Putting 50watts on a JL W7 probably wouldn't even make the cone move.

Subs that have high efficiency ratings can play louder with LESS power, but they still need SOME power.
Subs, ( especially GOOD subs ), have a higher power rating, and a lower efficiency rating because they are made for high power.
They NEED high power.

SQcomp is right though, all systems must have all the gains set correctly.
You cannot use an amp gain knob as a "volume" knob.
And all your components must MATCH each other.
Don't buy a 2,000watt RMS sub, and put a 400watt amp on it.
Don't buy a 500watt RMS max sub, and hook it to a 1,500 watt RMS amp.
You are just wasting money.

You CAN run a larger amp on a weaker sub, you just need to turn the gain down on the amp.
The question is, WHY would you do this?

My sub is rated at 500watts RMS max, and I have it hooked to an amp that puts out 400watts RMS.
My gain is set around the 10 o`clock position, my preamp outs are around 2.2v.
My sub sounds very nice, and my sub and amp run cool.
My amp barely gets warm, even after blasting it for an hour straight.
( my sub amp has a 2ohm load on it, at 4ohm load... it never even got warm. )

Maybe I am totally wrong, but I read articles and specs, and I see people with opinions that contradict what I read sometimes.
I know you guys have lots of experience, and I am not challenging your experience. I am just confused by what you just said about a 10 watt amp powering a 12" subwoofer.

I NEVER heard of anything like that.

Don't blindly trust the information coming from the person that has something to gain from you.

Is there such thing as too small of an amp? No
Do I recommend buying a bigger amp than you need? Kinda, for people who know audio I do, for people who can't set gains & eq levels properly I don't.
Will clipping hurt a sub? No, but the extra heat that it causes could toast your coil if you have too much total power going to the sub... furthermore, for a fully clipped signal (square signal) you'll have 20% less voice coil cooling due to the decrease in cone movement... so if you had a 1000w sub... now it can only take 800watts.... if you had a 800watt amp and are now clipping it... you could be pushing close to 1600rms. if you had a 300watt amp... you are still below the 800rms mark even with a fully clipped signal.

Manufacturers say things for two reasons...
1) to make money
2) to teach the ignorant, without getting technical - therefore, a lot of what they say isn't exactly true, but for the masses, it'll generally steer them in the right direction... however, the whole issue with amp size/clipping... they're in it for money. Clipping is a problem that stems out of GREED (for more spl) or ignorance (in not knowing how to set gains & eq levels). Neither will be fixed or even bandaged with simply buying a larger amp.. in fact, your chances of cooking your sub if you have a larger amp are significantly higher, because you won't have to clip as much to reach the thermal limits of the sub... Clipping is a nasty sounding distortion too... its rare that people have a 100% clipped signal.... but its also not uncommon for people to have a clippless signal.




Oh yeah... I think I saw something about size of cone being better or worse depending on the music you listen to.... cone size has NO EFFECT on how tight or sloppy a sub sounds. That is all determined by the Le of the voice coil, the design of the box, and the group delay & frequency response peaks. 8's can play as low as 15's, tho they usually aren't designed too, 15's can be just as tight as 8's... tho people usually don't design their installs to sound that way.

[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.

[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...

[Alien Mantis]

Originally Posted by talnlnky

8's can play as low as 15's, tho they usually aren't designed too, 15's can be just as tight as 8's... tho people usually don't design their installs to sound that way.

You are correct, but the reason people don't use 8's for 25hz bass is because at that frequency, you need eight 8's to be LOUD.
It's WAY cheaper and easier to just run a pair of 12's instead.

And the same goes for 15's.
If you want tight bass around 80hz, why run a giant 15" sub, stuff it in a small sealed box, and put a big power-sucking amp on it just to make it play tight?
Instead, run a pair of cheap 8's or 10's.
Less space, less power needed.

You are totally correct, you CAN get anything to play anything.
It's just not the practical thing to do.
( but when has "car audio" ever been about "practical" ? )

[Alien Mantis]

Originally Posted by talnlnky

Don't blindly trust the information coming from the person that has something to gain from you.

Manufacturers say things for two reasons...
1) to make money
2) to teach the ignorant, without getting technical - therefore, a lot of what they say isn't exactly true, but for the masses, it'll generally steer them in the right direction.

I agree.

But the manufacturers recommendations are a good reference.
Their information is not incorrect, it just might be somewhat incomplete.
Alpine gives you good information on how to treat their subs for maximum performance.
Remember, these companies want you to be SATISFIED with their products.
They want your install to be successful.
They do NOT want you to burn up your new subwoofer in 3 days, and send it back to them for a FREE warranty replacement.
So they are going to do their best to steer you in the right direction.

If you like their products, you will buy them again, and you will tell your friends to try them.

If you have bad experiences with their products, you will most likely NOT ever buy their products again, and "word-of-mouth" negative publicity can kill their sales numbers.

We all have certain brands we stay away from. And we all have certain brands we like to use.

For me, it is always "bang for the buck", how well the products are engineered and assembled, and how good is their customer support after the sale.
After that, comes product appearance.

If I am satisfied in ALL those areas.... they got my money!

Anyone can pay $600 and get a really nice subwoofer.
But can you get a really nice subwoofer for $100?

THAT is why I am in love with the Alpine Type-R.

[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.

[talnlnky]

Originally Posted by Alien Mantis

You are correct, but the reason people don't use 8's for 25hz bass is because at that frequency, you need eight 8's to be LOUD.
It's WAY cheaper and easier to just run a pair of 12's instead.

And the same goes for 15's.
If you want tight bass around 80hz, why run a giant 15" sub, stuff it in a small sealed box, and put a big power-sucking amp on it just to make it play tight?
Instead, run a pair of cheap 8's or 10's.
Less space, less power needed.

You are totally correct, you CAN get anything to play anything.
It's just not the practical thing to do.
( but when has "car audio" ever been about "practical" ? )

agreed, there is always a tradeoff.... or even many tradeoffs. If you do an install with eight 8's... your tradeoff is going to be price... the benefit will be efficiency. So, what you lose in money spent on subs... you'll at least partially make up on the cost of a sub amp (if you just want a specific dB goal) and also the lack of having to upgrade the big 3, alternator, or battery(s). Also, smaller cones proportionally require smaller box sizes (so you can fit more in the same sized box).

explanation: take an 84dB @ 1w/1m 8" sub... compare that to the 15" which will play 88dB 1w/1m... if you give each sub 1watt of power, there will be a +4dB difference in favor of the 15" sub.

considering +3dB change in output for every doubling in cone area you get the following...

1 = 84dB
2= 87dB
4 = 90dB
8 = 93dB

all of a sudden your +4 dB advantage for the 15" turned into a -5dB difference/disadvantage.

now, I was just throwing out numbers, I wasn't taking real specs from real subs... but 88dB for a 15" is reasonable... and so is 84 for an 8". You get the picture.

I had a friend who did an install with eight $50 8" subs and it was actually one of the loudest street beater vehicles I've heard... and he only had 150watts of power. Funny thing is... he could've safely used upwards of 1,000watts... tho... realistically he would've only gained about 5-6dB.... theoretically he would've gained about 7.5-8dB


EDIT: I've always been about best bang for the buck....take my gear list for example... I have something like $4k worth in products... but only one or two things were bought new, and at least one item wasn't functional when I bought it (had to do a lil solding work). For that, I was rewarded with $4k worth in gear for a quarter of the cost... all legit sales, nothing hot or anything. Not everybody is all about best bang for the buck tho... so I preach more than just my preferences.

Like alluded to above, some people care more about cargo area, for them... going with dual or tri 8's might be a better option than going with a single 12". Or if they really wanted to experiment... there are a handful of 5.25/6.5/7" speakers that can actually be considered subs that require insanely small boxes, even when ported.


EDIT: on another note... I kinda disagree with about a company not wanting you to blow up your gear. Of course they don't want you doing it in the first three days.... or maybe not even in the first 6 months... but a year or two down the road... Oh yeah... Many people will go back and buy that same gear if they liked it the first time... even if it did die an early death.... Look at all the people who continued to drive american cars despite decades of horrible reliability. Granted ford is now getting better, but I still see chevy's gmc's, and pontiacs everywhere I go.

John deere almost drove themselves out of business because there 2cylinder tractors were too reliable, nobody ever had to replace parts. They eventually figured out that if they created 6cylinder tractors that people would buy them, despite not being as reliable simply because they would be more powerful... and the company would then get repeat customers.

Audio companies are the same way... the tricks is finding the proper balance.. some of the companies that say their subs can handle 1000w are flat out lying... sure the coil won't die today... but a year later it will. for every 10degrees farenheit you lower the temperature of a circuit (voice coils are no different)... you double its life. Every speaker will die eventually due to a burnt coil if given enough time... the time will be dependent on how much power that coil sees. I've given 800watts to a 10watt speaker before. It lasted 8-10seconds. The mathing speaker to it was over 10years old... and still kicking strong... course it had only been seeing 5-10watts of power, but give it another 10-20years and it would've died too.

[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.

[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.

[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]

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.

[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.