DIYMobileAudio.com Car Stereo Forum banner
1 - 20 of 25 Posts

· Registered
Joined
·
2,440 Posts
I was looking at this 12" sub for the trunk of my car:

Would this go in a bigger box than recommended? And tune around 32hz?
Yes, but why would you?

Assuming you're talking ported and at what power level?

It's going to get REAL peaky at the tuning frequency REAL fast...

Here's 2 cuft tuned to 32Hz:
309337


Needs 25Hz HP and between the HP and the reduction in excursion at port frequency that pushes the wattage up to 8,000 Watts before xmax...
309338


Even with Cabin Gain it's still peaky and you still have to have a 6" port ~33" long...
309339


The bigger the box the bigger the peak is going to be.
 

· Registered
Joined
·
2,440 Posts
Not really ... Yes, it would 'work' but at 12.5mm you're barely even moving the cone.

There are many - many better options for 2.2 @ 32 with 1500 Watts. As I said previously, you would need about 8,000 Watts to make the SQL really work in such a configuration.

Better Options:
Adire Audio Brahma 15 = Green
Dayton 15HO-4 = Blue
American Bass XFL15-22 = Yellow
309443
 

· Registered
Joined
·
2,440 Posts
Not to take anything away from Nick - he's in the business of selling not trying to advise you on what would sound the best given very specific parameters... the SQL12 will work 'best' in 1.2-1.5 ported at 25-28 Hz but again, unless you plan on upping your amplifier game in the near future there are better candidates.

We are not refuting that it would work simply that they are better choices for better Sound Quality, more output and less expense than the SQL12 if you're dead set on using 2.2 @ 32 Ported. The SQL12 works best when fed WAY more power than you're contemplating (unless you have a vastly underrated amplifier that's rated 1,500 Watts at 4 Ohms at something like 0.001% Distortion...

The reason you want flat non-anechoic response is so that you don't end up with a nasty resonance in the vehicle. The flatter the response is of the "Speaker" (Driver + Enclosure + Alignment + Tuning) the less chance you have of creating a huge peak or null once you install in-car. The doubling you can get from a standing wave inside the vehicle is pretty easy to EQ out by cutting -3dB at that frequency without any side effects or problems that come from trying to "add" back in the frequencies you are missing since every +3dB of EQ you add requires doubling the wattage at that frequency. By the time you EQ out the peak so it's not a one-note wonder and EQ back in the upper frequencies you've usually reduced you're overall output by at least half.

Remember that every 3dB is equal to doubling the volume we perceive so if you add up the area under these curves the Dayton is easily 4x as loud as the SQL12 from 40-80Hz... and that doesn't include any harmonics below the tuning point. The SQL12 will make the whole car rattle and buzz at 32 Hz but then go MIA at anything above 40 Hz - the Dayton has the virtually same output at 32 Hz (-1dB) but with 4x the output everywhere else.

SQL12 = $350
HO15 = $240

The only reason to consider the SQL12 in this scenario is if you're planning to use a different enclosure and more specifically a different amp later on or you simply already own all of this equipment.
309473
 

· Registered
Joined
·
2,440 Posts
Actually Nick just told me to drop the volume of my box to 1.5ft3. I don't like a 12" in that small of a box. Can it actually work with 1.5ft3?
How one 12 sounds in a box doesn't predict how any other 12 will sound... the SQL actually "sounds" best in 0.7 cuft sealed which is basically a cube big enough to fit the basket and motor into with some space for the pole vent. The labyrinth slot port design I posted on your other thread would make the SQL12 really pound but only if you have 3-5 kW of clean power to feed it... it truly is one of the most power hungry subs I've used except for some 24" IB beasts that I've installed for Home Theater.
 

· Registered
Joined
·
2,440 Posts
The Dayton HO15-4 wants 2.7 @ 22 but 2.2 @ 25 is a better alignment for cabin gain and I've included 2.2 @ 32 for reference (which isn't nearly as bad as the SQL cause the slope is still gentle enough to give it good in car response.)
309474
 

· Registered
Joined
·
2,440 Posts
On the parts express website it says 2.7ft3 tuned at 30hz. But would a bigger box be louder?
It can be, the larger the box the less Q (damping) controlling the motion of the woofer but if you go too big then it hurts power handling...
But let's start over and define exactly what it is you're looking for...
  1. You've said the trunk of your car - what car?
  2. You've mentioned 1,500 Watts - what amp?
  3. What's the rest of your signal chain?
  4. What's the rest of your system - all speakers and amps?
  5. It's pretty obvious you're looking for maximum output - do you care about Sound Quality at all or are you simply looking for the biggest bang for the buck?
  6. Enclosure - do you have one already or are you building one, buying one, or having one made?
  7. What's your reference for Subs - what have you heard that really impressed or created the sound you're looking for in your ride?
  8. Budget for everything you are planning to buy and if not a specific number then a range please.
Please be specific with brand names and model numbers of all equipment and include everything in the signal chain from the HU to the speaker by replying to each number.

Include any other specifics you can think of that aren't included above.
 

· Registered
Joined
·
90 Posts
Discussion Starter · #16 ·
1. 2016 honda civic ext
Incriminator audio amp Incriminator Audio IA10.1 Monoblock 1200W Class D Amplifier
All stock speakers throughout and keeping stock radio so I need a line output converter
No amp for speakers just want a sub amp. The speakers are pretty decent as is.
Yes I want SQL both SQ and SPL
I will have the box made
I want my stereo to sound anywhere close to my home theater. My home theater sounds better than any stereo I have heard. I just don't want to spend a ton of money on my car because I am not in the car much.
 

· Registered
Joined
·
2,440 Posts
daloudin Your WinISD results aren't what they should be. At 2.7ft3 tuned at 22hz is not what that sub was intended for. Why not 2.7ft3 tuned at 30hz like it says on partsexpress?
The results are what they are... they are based on mathematical analysis of the T/S specs and 2.7 at 22 is a full on SQ alignment typically used in creating speakers for use in the home - this is where WinISD defaults to when you first start a new alignment. 2.7 at 30 is a nod to the cabin gain and increasing the output above tuning to match the extra cabin gain. There's a mathematical point at which any alignment gives you the best compromise between output and low frequency extension. When pursuing SQ you want the slowest and shallowest rolloff possible as frequency descends. The alignment that has the slowest rolloff is Infinite Baffle, then sealed and then ported, the rate at which a ported box rolls off depends on the relationship between the box size and the tuning point. For the best SQ this usually means a much lower tuning point. When pursuing SPL or "Burp Boxes" then the tuning point is tailored to the driver, the box and the vehicle to maximize the gain at the expense of any output above or below the tuning point. The advantage that putting a sub in a car gives you is the cabin gain that increases the output below the frequency that coincides with the maximum dimension of the anechoic space. For your car that's around 70-80Hz so we'll use 80 to calculate cabin gain and since it's a smaller cabin and you are going ported we'll limit the lower end gain to 20Hz since you'll need an infrasonic filter at that point to prevent over-excursion in a ported enclosure.

Back to your specifics - you have 1200 Watts at 1 Ohm or 800 Watts at 2 Ohms or 400 Watts at 4 Ohms and while you can use the Dayton HO15-4 at 400 Watts we will be looking at mostly DVC 2 Ohm Subs to give you the 1 Ohm load you need to maximize your amplifier.

At 1,200 Watts the IDMax is slightly louder overall but the Brahma is neck and neck and based on tuning alignment you could make either one louder at certain frequencies. The IDMax is a little less peaky for better SQ though...

The white trace is your TC Sounds 7 cuft at 20 Hz and 1,000 Watts modeled in to your car (not that you would but just for reference) and at 1,200 Watts the IDMax most closely resembles the curve of that Subwoofer model, the IDMax and Brahma are on 1,200 Watts and the Dayton HO is at 400 Watts, the Pink is the SQL12 on 1,200 Watts and then the Orange is the SQL12 in a SQ Ported box on 6,000 Watts:
309509


So all of that to say that the SQL12D2 will work fine and is the equal of the IDMax at 1,200 Watts but whereas the IDMax is at xmax on 1,200 Watts, the SQL12 can handle 5x more power for when you get ready to up your amplifier game but keep in mind that all that extra power is only going to net you about +5dB but that's almost 4x as loud.

And here's the nexus of modeling and the limit of what WinISD will let me do in one run.. it starts getting really flaky and won't let you make changes at this point but this goes to show what you can do with one woofer - these are all the SQL12: the Yellow is that best SQ alignment
The Reds are all 1.358 cuft at different frequencies.
Greens are all 1.8 cuft at the same tuning points.
Pinks are all 2.3 cuft at the same tuning points.
Teal are all 3.3 cuft at the same tuning points.
The point being that you can make it look any way you want and easily change the output by +/- 6dB ...
309511
 

· Registered
Joined
·
90 Posts
Discussion Starter · #20 · (Edited)
Why do you have the ID max in a 5cuft box tuned at 24hz and the brahma at 30hz? I would do the brahma at 32hz for a daily driver at 2.0cuft. What size box does the ID max go in and where should it be tuned? On woofers etc it says the IDmax goes in a 2.25cuft box tuned at 35hz. Here:
 
1 - 20 of 25 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top