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Jake the snake

Need help finding my perfect subwoofer

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Im looking for a subwoofer either 8,10, or 12 inches with a low fs under 30. A qts between 5 and 5.6, also a decent xmax to support music down to 20 hz. I ask these requirements because i had 2 rockford p3 10s which i would buy again in a heartbeat if it werent for the fact that it can only go as low as 28 hz accord to sonicelectronix. i can vouch that it doesnt hit low notes without a loud sharp sound which i thought was coil hitting magnet. So the sub must also play down to 20 hz full power and be at or under 250$. I have also used a morel primo 12 which was a decent replacement but needs more xmax and a bit higher qts but it does hit 20 hz. I am considering buying a cadence s1 w8 but want some feedback from everyone here to see if they have any helpful experiences with similar taste in subwoofers.

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enclosure will make the biggest difference

fs is just a resonance frequency free air not in an enclosure

someone correct me if i am wrong very tired right now and got to be up at 2am


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Yes what you said is true. I am using that value as a guide for how loose the suspension is. When the suspention is loose and you have a higher qts the higer bass notes of 40hz-80 even 120hz were more pronounced or just sounded more natural to me. Also the suspension being loose allows for the sub to recreate low notes better as long as it has enough xmax to allow for the actual air mass to in the end result match the output of the higher more easier for amp to output frequencies. So in my expierience i have a fs of 26 very easy to move suspension and with it being easier to move in the mid 20s the sub has more defined low end curve as well as leaving space in the audio spectrum for cabin gain and port tune to fill in the 30-40 hz ranger, i have a qts of 5 which allows the sub to play a wider verioty of types of bass notes due to that qts is a measure of the quickness of the drivers movements ie giving you a false sense of output on high notes which is actually more defined sound, and finally an xmax of 14 which allows enough air output for low notes so that the port tune can be higher giving you more upper range. I have had a sub that had 40 fs like 3.8 qts and idk how much xmax but lets say 16. The subs was not cleanly reproducing bass because the suspension was tite and it wasnt quick enough to reproduce quicker puchy bass. Finally the higher xmax even with the help of a low box tune did not provide enouge low bass out put and it had a bad peak up high and down low.

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So let me make sure I understand.  You are looking for a driver with a sub-30 fs, and a qts around 5 that can hit the low lows but is still musical enough to play some of this higher frequencies as well, is that right?

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Because you raise a couple of questions that need to be addressed.

1) if sonic told you a p3 10 can't hit below 28hz they are off their game today...  that sub hits below 28hz in free air.  With the proper enclosure that sub is all over 28hz... although not with a prefab box tuned to 42hz from sonic it isn't, and that's likely the awful noise you were hearing a low frequencies... It is called "unloading" and it happens when you are playing frequencies below box tuning.  Think of the fb (box tuning point) as a point of air resistance for your sub. Below it, no air resistance and sub bottoms out.

What sonic should be telling you is A) If you want to play below 28hz with any kind of efficiency you should really think 12" or 15" driver, not that your 10" can't, and B ) You need to pay careful attention to your box tuning if you want to play that low.

2) If you tune your box higher to hit midranges, and try to depend on xmas to deliver the low lows in that high tuned box, your sub is going to "unload" at the lower frequencies and sound like hell while it breaks itself at it reaches its mechanical limits.  You seriously don't want to play more than 1/2 octave or so below tuning without risking serious damage unless this is some sort of 16 watt sq setup (wouldn't be the first and I'm not complaining if that is your thing)

For your purposes I would recommend you find a 12 inch sub with an fs 30 - 35 and a box tuned to around 30hz made close to the manufacturers recommended size.  That is likely going to give you a 3db rolloff right around that mid 20s range you crave  And generally speaking... a sub with fs in the 30s, a qts .45 - .55, a box size roughly 1.5xVas tuned to around 30... gives you a flat enough frequency response that you can hit the lows and still hit those high[er] notes too.

You can always plug your driver and box specifications into a program like WinISD to get some simulations for the type of response you will get at difference frequencies.

Cheers.

Edited by abdc
value corrected

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If you did decide you wanted to stick with your p3 10" (not recommending you do but whatever floats your boat) i just wanted to show you why and how you can play below 28 hz (which what, btw, are you doing below 28 anyway. I mean Jeezy hypnotize is 32hz) with these WinISD charts.

Here is a box model designed by WinISD specifically to give your P310 a flat frequency response.  It requires roughly a 2cu. ft. box tuned to roughly 21hz:

 

5a1010f3af4ea_p3102flatresponse.thumb.png.54ffc3e7ff6c76a5ad5656ff5f3959b5.png

^As you can see below 28hz is not a problem.  The problem you will have here is playing the sub at its full rated power levels.  While this box gives you a nice flat response, it is also fairly large to accomplish this and you risk bottoming out if you play it too hard.  You are probably safe up to about 75% RMS.

 

 

OR... don't worry about a completely flat response and spare yourself from building a box to those specifications (unless that's your thing) and do it my way. 

If I were going to buy that sub right there very moment, I would buy this Atrend box which is 1.5 cu. ft. tuned to 32hz.

5a1012c61cf48_p3102atrend.thumb.png.2c81c406a824fcfe06f757910b9b7c0d.png

^As you can see this sub/box combo would give you a nice slow rise from 100hz down to the mid 30s where you would peak at plus 5 or 6 decibels before you start to slowly roll off toward your f3 all the way down a 26hz.  You may think "but I don't want to roll off..." but with cabin gain it is still going to be plenty loud so don't even worry about it.  If this is not some meticulously intricate SQ system you won't even notice the difference.  And the nice thing about using this box size, you can play at your subs full rms rated power right down to 26hz without having to listen to sonic tell you no.

 

Hope these examples help, and if I have somehow missed the point then let me know and we can back track.

 

PS download WinISD HERE.

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This coffee is awesome... so anyway, if you are not satisfied with those suggestions, two things...

1) Play this: 

Still think you need 20hz? Ok.

2) You might have to give up on that 'loose' suspension you wanted because you are going to need a tight suspension to handle that kind of low end excursion without hurting the sub. You mentioned coned slapping magnet before... yeah lets not do that anymore.  Putting aside TS parameters, you need something with a big honkin magnet, heavy duty coils, extra spiders, and a big fat surround. 

I'm a DC Audio fan myself.  A level 4 would get the job done for you and still remain fairly 'musical', I doing an XL build myself right now.  Otherwise the SSA XCON or Sundown X would be good options.  All of these subs would be much heavier and double your power requirements per sub, but would definitely accomplish your low end goal with the proper box.

Get some mid-bass drivers and tweeters in your doors to handle everything else.  If you want a driver to hit 20 hz, just let it worry about 20hz.

 

OR simply be willing to go up to a 15 or 18 inch driver and accomplish the same thing with less power.

Edited by abdc
SSA

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Your definatly got it right. My interest in the smaller subs is the quickness of the driver due to its decreased mass due to over size difference between an 8 and 12. I was ready to get the 15 inch version of the p3 but moving from a 10 to 12 inch i noticed some differences that i didnt like. The higher notes were no where near as defined and i felt as if the mass of the driver was hindering qts performance even though the new 12 only had at most a .3 qts difference being 4.7, the p3 is 5.0. I also have the new 12 which is a morel primo 12 in a box designed for a jl w6 12 so the box is not made specifically for the primo. Now the other thought on the cause of the horrible sound was that it was unloading. at the time i didnt know the p3s even according to rockford wouldnt go below 28 at or above rated power. I had two d2 10s and im not sure what impedence load i ended up wiring them but i had only a 300-500 watt amp powering both of them and at close to max undistorted volume unloading would happen. I play a lot of slowed music so there are plety of songs that are going under 30 also. I am definatly looking in the lower power range of subs as well because my current daily driver has no ho alt option and it might never because its a mazda and the indistry isnt interested in mazda because they make it hard for installers to do anything to get the system right. Im not sure what the port length width or height was for the box with the p3 and i also dont have the p3s anymore because i sold them to upgrade to 2 american bass xr 12s and a cresendo 2000. I now have sold both amp and subs because i didnt like the low qts and 35 fs of the xr 12s and the new car cant handle 2500 watts for more than 2 songs close to max volume. 2500 becaise i have a jl 400/4xd under front passanger seat. I will try to include a picture from where i bought the box. I do know internal volume was 1.5 for each 10 inch p3.

Screenshot_2017-11-18-15-08-45.png

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