Featured What should my subsonic filter be set to?

[AndrewMelon2121]

Hello everyone,

Sorry for the ignorance, I’m still learning about subwoofer tuning and just wanted to get some opinions on my current setup.

I had the system professionally tuned a while ago, and the subsonic filter was set to around 50 Hz. I’m a bit confused by that setting because I’d like to get more deep bass out of the system. On some songs with lower bass notes, the subwoofer doesn’t seem to have much output, while the higher bass comes through much more clearly.

My setup is:

Hertz MP 300 D4.3 12" subwoofer
Morel MPD 1.500 mono amplifier
Aerpro UBOX12 ported enclosure
Added poly Fill
Box volume: 24 L
LPF: around 80 Hz (not too sure)
Subsonic filter: around 50 Hz


Would 50 Hz be considered too high for a ported enclosure tuned to around 43 Hz?

I am afraid to many any adjustments to the subsonic filter just yet so any advice would be much appreciated, thanks everyone.
Also sorry for the bad photo

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[CarAudio.com - Hal AI Bots]

Hello everyone,

Sorry for the ignorance, I’m still learning about subwoofer tuning and just wanted to get some opinions on my current setup.

I had the system professionally tuned a while ago, and the subsonic filter was set to around 50 Hz. I’m a bit confused by that setting because I’d like to get more deep bass out of the system. On some songs with lower bass notes, the subwoofer doesn’t seem to have much output, while the higher bass comes through much more clearly.

My setup is:

Hertz MP 300 D4.3 12" subwoofer
Morel MPD 1.500 mono amplifier
Aerpro UBOX12 ported enclosure
Added poly Fill
Box volume: 24 L
LPF: around 80 Hz (not too sure)
Subsonic filter: around 50 Hz


Would 50 Hz be considered too high for a ported enclosure tuned to around 43 Hz?

I am afraid to many any adjustments to the subsonic filter just yet so any advice would be much appreciated, thanks everyone.
Also sorry for the bad photo

It sounds like you're on the right track with your subwoofer setup, but there are a few points to consider regarding your subsonic filter and tuning.

1. Subsonic Filter Setting: Setting your subsonic filter to 50 Hz can be relatively high for a ported enclosure tuned to around 43 Hz. The purpose of the subsonic filter is to prevent frequencies below the enclosure's tuning from being amplified, which can cause distortion or damage to the subwoofer. If you want deeper bass, you might consider lowering the subsonic filter to around 30-35 Hz to allow more of those lower notes to pass through while still protecting the driver.

2. Ported Enclosure: Typically, for a ported enclosure, tuning is centered around the port frequency. Since yours is tuned to 43 Hz, the enclosure will be most efficient at that frequency. Lowering the subsonic filter setting could help in getting more output at lower frequencies.

3. LPF (Low-Pass Filter): Your low-pass filter set around 80 Hz seems reasonable, but adjusting this down (perhaps to 60-70 Hz) may help blend the subwoofer output more effectively with your main speakers.

4. Listening Tests: Make adjustments in small increments and listen to a variety of music, focusing on tracks that showcase low bass. This way, you can find a balance that sounds best for your preferences.

5. Caution with Adjustments: Always take it slow and gradually adjust your settings. Make one change at a time and take note of how it affects the sound.

Feel free to ask more questions as you experiment!

 

[Doxquzme Premium Member]

Skip the polyfill, no need for it in a ported enclosure- there aren't any standing waves to contend with, no need to put something in the box to deal with something that isn't present.

Your subsonic filter should be no less than 1/2 octave below the tuning frequency of the box.

Tuned frequency of the enclosure:

43hz HPF 30.4hz
40hz HPF at 28.3
35hz HPF at 24.75
30hz HPF at 21.21

Here's the math:

To calculate the exact frequency a specific number of octaves away from a starting frequency, use this formula:
\(f_{new}=f_{start}\times 2^{n}\)

Formula Breakdown

• \(f_{new}\): The target frequency you want to find.
• \(f_{start}\): Your starting frequency (in Hertz).
• \(2\): The base multiplier, because an octave represents a doubling or halving of frequency.
• \(n\): The number of octaves. Use a positive number to go up, and a negative number to go down.

Step-by-Step Example (Half an Octave Below 40 Hz)

1. Identify your values:
   • \(f_{start} = 40\)
   • \(n = -0.5\) (negative because you are going below, and \(0.5\) for half an octave)
2. Plug them into the formula:
   \(f_{new}=40\times 2^{-0.5}\)
3. Solve the exponent:
   • \(2^{-0.5}\) is mathematically the same as \(\frac{1}{\sqrt{2}}\), which is approximately 0.7071.
4. Multiply:

The same applies to any frequency you want to calculate; just change the starting number.

 

[AndrewMelon2121]

Skip the polyfill, no need for it in a ported enclosure- there aren't any standing waves to contend with, no need to put something in the box to deal with something that isn't present.

Your subsonic filter should be no less than 1/2 octave below the tuning frequency of the box.

Tuned frequency of the enclosure:

43hz HPF 30.4hz
40hz HPF at 28.3
35hz HPF at 24.75
30hz HPF at 21.21

Here's the math:

To calculate the exact frequency a specific number of octaves away from a starting frequency, use this formula:
\(f_{new}=f_{start}\times 2^{n}\)

Formula Breakdown

• \(f_{new}\): The target frequency you want to find.
• \(f_{start}\): Your starting frequency (in Hertz).
• \(2\): The base multiplier, because an octave represents a doubling or halving of frequency.
• \(n\): The number of octaves. Use a positive number to go up, and a negative number to go down.

Step-by-Step Example (Half an Octave Below 40 Hz)

1. Identify your values:
   • \(f_{start} = 40\)
   • \(n = -0.5\) (negative because you are going below, and \(0.5\) for half an octave)
2. Plug them into the formula:
   \(f_{new}=40\times 2^{-0.5}\)
3. Solve the exponent:
   • \(2^{-0.5}\) is mathematically the same as \(\frac{1}{\sqrt{2}}\), which is approximately 0.7071.
4. Multiply:

The same applies to any frequency you want to calculate; just change the starting number.

Hello doxquzme, I appreciate the advice. Ngl I'm quite hesitant to remove the subwoofer and etc so I might just leave the polyfill in. Would that effect the calculations? Also, what would be a very safe number to aim for at first?

 

[Doxquzme Premium Member]

Nope, not an issue really.

I often add that bit f of info as people who come along later might be building a bass reflex enclosure and wonder about polyfill too.

It looks nice...

Jk, it's functional in sealed enclosures, more specifically in midbass and midrange enclosures where there are a lot of standing waves that may occur.

It reduces intermodulated distortion in bass enclosures and, to a degree, tricks the driver into thinking it'sin a bigger box.

Most of that kind of goes out the window in the sub-100 Hz bass reflex enclosures like yours.

As for the setting on that amp, I'm guessing it's somewhere between 11 AM and 1 PM for a 30 Hz HPF.

Set it at 10 AM, move it to the right, and stop when you hear it affecting the low end, then dial it back a bit.