question about big box and low tuning

[riddla 10+ year member]

I have a box that is tuned to 27hz and its about 3.5cft after sub displacement. I have noticed that it belts out the lows with some force (great) but its no good at higher notes. What I wanted to know is, is this bad for the subwoofers in general if a box only plays low notes but cant produce the higher frequencies and can the subwoofers be damaged as a result. Would setting phase and subsonic make a difference. My crossover point is set to 32hz and it seems mor like a 1 note box? any input guys

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[DidUHearThat? 10+ year member]

I have a box that is tuned to 27hz and its about 3.5cft after sub displacement. I have noticed that it belts out the lows with some force (great) but its no good at higher notes. What I wanted to know is, is this bad for the subwoofers in general if a box only plays low notes but cant produce the higher frequencies and can the subwoofers be damaged as a result. Would setting phase and subsonic make a difference. My crossover point is set to 32hz and it seems mor like a 1 note box? any input guys

That's your problem. 32 hz is unusually low. Raise your LPF on the crossover to 50 -65 hz. You can keep raising it till is begins to sound bad, then dial it back down a bit. Most sub boxes will stop sounding good around 80 -100 hz. Also the bass becomes more directional making it more obvious your bass is comming from behind you. Your LPF should be somewhere between 50-80 hz. 60 hz is common.

Your sub sonic filter should be set around 20 hz. Phase is not at issue here, but it should be adjusted till the bass sounds tight and loud at the listening position, or left at zero.

 

[riddla 10+ year member]

thanx for the reply, is there that much of a difference from 27hz to 32hz ? I will have a play around with the settings you mentioned and see how it goes.

Also regarding my question, can the subs be damaged

 

[tez4life Premium Member]

You will be fine, my last box for my single 15" was 4ft net @ 28hz. My sub (Soundsplinter RLp) had no issues with the upper as well as the lower notes. Sub wont be damage at all.

And, as mention above, your crossover point is your biggest problem, raise it, and you will def see a improvement.

 

[DidUHearThat? 10+ year member]

27 hz is where your box is designed to peak. Basically the lowest point it will play. It's output drops quickly below 27 hz. Your crossover point is a compeltly unrelated matter. It represents the HIGHEST frequency that is being set to your amp. By setting it at 32 hz, your sub is only playing from about 27 hz to about 32 hz .That's a band width of about 5 hz. So yeah, it sounds like one a one note sub, because it is. That's very narrow.

Raising the crossover point allows the "higher" sub frequencies to get to the amp, then to the sub. The sub sonic filter sets the lowest frequency that can get to your amp, then to the sub. It should be about 20 hz.

Raising the crossover point to 60 hz will allow your sub to play from around 60 hz down to below 27 hz. (the slopes are not sudden, but actuall fall off over several frequencies. 27 hz and 60 hz is where the slope start your actual bandwidth will probably be around 20 hz - 70 hz).

 

[riddla 10+ year member]

You will be fine, my last box for my single 15" was 4ft net @ 28hz. My sub (Soundsplinter RLp) had no issues with the upper as well as the lower notes. Sub wont be damage at all.
And, as mention above, your crossover point is your biggest problem, raise it, and you will def see a improvement.

Great, I will give it a go //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[riddla 10+ year member]

27 hz is where your box is designed to peak. Basically the lowest point it will play. It's output drops quickly below 27 hz. Your crossover point is a compeltly unrelated matter. It represents the HIGHEST frequency that is being set to your amp. By setting it at 32 hz, your sub is only playing from about 27 hz to about 32 hz .That's a band width of about 5 hz. So yeah, it sounds like one a one note sub, because it is. That's very narrow.
Raising the crossover point allows the "higher" sub frequencies to get to the amp, then to the sub. The sub sonic filter sets the lowest frequency that can get to your amp, then to the sub. It should be about 20 hz.

Raising the crossover point to 60 hz will allow your sub to play from around 60 hz down to below 27 hz. (the slopes are not sudden, but actuall fall off over several frequencies. 27 hz and 60 hz is where the slope start your actual bandwidth will probably be around 20 hz - 70 hz).

Now I understand the concept. Its much clearer now, Ima have a play around this wkend and report back //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[DidUHearThat? 10+ year member]

Also turn off (or down to zero) any bass boost on the amp.

 

[riddla 10+ year member]

Yes, I never use bass boost from previous advise. U all been a great help //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif