Jump to content

Recommended Posts

55 minutes ago, CFD said:

Do you have the impedence meter/signal generator? You could use it to find your true port tuning as the weather changes. Maybe you could also test whether it moves when the car is completely open (windows, hatch, etc) verses the entire car closed. I'd be interested in seeing what exactly happens to the box tuning as the temperature changes and when box is in a more open environment versed more closed.

 

That box looks great btw.

I do have an AMM-1, SSA SPL meter and signal generator.

 

The enclosure was tuned to 35 hz. That being said 52 hz is my lowest impedance at 2.4 ohms at half volume. Unfortunately this is not ideal for getting the most SPL for me at the moment. I like that it's almost 150 at 32 hz on a non-wall or 4th/6th order.

 

I've been mostly windows up to know what the car can do if I do a competition. I did a few sweep tests in August and windows open or closed didn't change significantly. I'm sure I have created alot of "holes" in my cars envelope due to my previous system (4 12's on 3k).  I will be doing more testing in a couple of weeks to see how much open window(s) affect the SPL in this cold weather.

 

My amps aren't doing what I expected so i'm going to more testing to see how far off they are compared to their rated power (I may run them separately at 1 ohm and match the gains vs having them at 2 ohm master/slave).  I may still have headroom and can adjust the gains but I don't know just yet. Nothing has shown clipping so that maybe where I'm losing some dbs.

 

 

 

 

 

 

Link to post
Share on other sites

  • Replies 26
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

Here's a few photos of what has been installed in my daily driver.   Headunit: Kenwood DMX905S Processor: Helix DSP Pro & Director Amplifiers: 2 Helix G-Four (Fronts and Mid Ba

The smaller the interior, the louder the vehicle can get based on the same sub. My Solara with a single 12 in a BP4 and 200 watts is louder than my F150 SuperCrew with 2-15's sealed and 1k watts. I ha

Thank you sir! I can't wait to meter it and see what it hits.

Posted Images

Any chance I could get some info on that box?

 

Like internal dimensions, air volume, length, width, height of the port.


Things seem kind of weird with how it's responding. Are the woofers moving a lot at 52 Hz? Usually at the tuning frequency the woofers move the least and the impedance is the least. It'd be really, really odd for your box to be tuned to 52 Hz yet peak under the tuning frequency I would think, and it would also be very odd for the box to be tuned to 35 Hz yet have the least impedance at 52 Hz... right? Would it not be impossible for a box to make peak SPL under the tuning frequency?


Usually a box tuned to something like 35 Hz will make peak output at like 40-50 Hz... I'm sure you know. Then rolling off at the tuning frequency and starting to unload.


I'm just trying to figure this out.

Edited by CFD
I should have asked for more details so I'm asking for more details plus my mind is potato
Link to post
Share on other sites
9 hours ago, CFD said:

Any chance I could get some info on that box?

 

Like internal dimensions, air volume, length, width, height of the port.


Things seem kind of weird with how it's responding. Are the woofers moving a lot at 52 Hz? Usually at the tuning frequency the woofers move the least and the impedance is the least. It'd be really, really odd for your box to be tuned to 52 Hz yet peak under the tuning frequency I would think, and it would also be very odd for the box to be tuned to 35 Hz yet have the least impedance at 52 Hz... right? Would it not be impossible for a box to make peak SPL under the tuning frequency?


Usually a box tuned to something like 35 Hz will make peak output at like 40-50 Hz... I'm sure you know. Then rolling off at the tuning frequency and starting to unload.


I'm just trying to figure this out.

Sorry I didn't respond earlier but I don't have the info at my home computer.

 

Box net volume including port 11.7 cubic ft.

Port Volume 1.21 cubic feet. (Port Length 28" Port Width 4" Port Depth 31")

Sub displacement .17 cubic feet.

Net Volume for the enclosure 10.15

 

Port was designed for 34 hz.

 DB Drive asks for 8.4 cubic feet for enclosure and 38hz tuning.

The FS for the sub is 38hz.

Edited by pnutz37
Link to post
Share on other sites

If the port is 4 inches tall, 28 inches wide, and 31 inches long then the tuning, I think, is more like 27 Hz

 

If the port is 4 inches tall, 31 inches wide, and 28 inches long then the tuning, I think, is more like 29.5 Hz.

 

I think the box might just be tuned lower than you think.... but that doesn't completely explain everything. 

 

I just used WinISD to get a gauge on what it's tuned at. I wasn't sure how to interpret your port measurements so I gave both ways I could interpret it.

Link to post
Share on other sites

I just read about that 28 Hz was one of the "most efficient" frequencies. I missed that. You're tuned lower than you thought I'm pretty sure.

 

If you want to get a 150 just to get one then You could probably get it by moving your port tuning up a couple different ways.

 

1. Shorten the port.

 

2. place solid objects in the box to take up some air volume. This will also bring the port tuning up some and you have a bit oversized box so you won't end up under the recommended box size.

 

Otherwize, you've got a great box for making lots of low low bass! :)

Link to post
Share on other sites
1 hour ago, CFD said:

If the port is 4 inches tall, 28 inches wide, and 31 inches long then the tuning, I think, is more like 27 Hz

 

If the port is 4 inches tall, 31 inches wide, and 28 inches long then the tuning, I think, is more like 29.5 Hz.

 

I think the box might just be tuned lower than you think.... but that doesn't completely explain everything. 

 

I just used WinISD to get a gauge on what it's tuned at. I wasn't sure how to interpret your port measurements so I gave both ways I could interpret it.

The port is your 2nd line item so potentially tuned at 29.5. I know that this vehicle behave a bit different compared to what I've done in the past. There isn't much space for wave development for the lower frequencies either.

Link to post
Share on other sites
1 hour ago, CFD said:

I just read about that 28 Hz was one of the "most efficient" frequencies. I missed that. You're tuned lower than you thought I'm pretty sure.

 

If you want to get a 150 just to get one then You could probably get it by moving your port tuning up a couple different ways.

 

1. Shorten the port.

 

2. place solid objects in the box to take up some air volume. This will also bring the port tuning up some and you have a bit oversized box so you won't end up under the recommended box size.

 

Otherwize, you've got a great box for making lots of low low bass! :)

I can try that to see if makes a difference. I also have the abilty to lengthen the port.

 

I could lower the tuning or raise depending on what I want to do.

 

I think I will be testing at 100% first before I succumb to adjusting my port size and lengths. It's a loud daily driver based on the looks I get at the stop lights....

  • Like (+1 Rep) 1
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    No registered users viewing this page.

  • Who's Online   0 Members, 0 Anonymous, 175 Guests (See full list)

    There are no registered users currently online




×
×
  • Create New...