# Best way to achieve flat subwoofer frequency response



## rovertnamrod (Dec 6, 2012)

What is the best way to have all the frequencies that a subwoofer plays output at the same volume. I have an Arc12d2 v2 and it gets quiet on the low frequencies. I would like those lows to be as loud as the rest of the frequencies. I would like to quiet the louder higher frequencies to match the loudness of the lower frequencies, rather than boosting the lower frequencies to match the loudness of the higher frequencies.


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## ZAKOH (Nov 26, 2010)

rovertnamrod said:


> What is the best way to have all the frequencies that a subwoofer plays output at the same volume. I have an Arc12d2 v2 and it gets quiet on the low frequencies.


How did you measure that? Normally human ear is not sensitive in lowest frequencies. 30Hz and below is mostly felt than heard. 20Hz is pretty much not heard at all. When I want to break in a subwoofer I play a 20Hz test tone because no one can hear it. If you would like to get a precise measurement, you need a special measurement microphone, software, etc. Parts-express is selling calibrated Dayton audio microphones. There is one with a built in interface that you can plug directly into a laptop. Granted, a truly flat frequency response probably should not be the goal. Most people don't like how it sounds and prefer bass to be a little louder. You do have a problem when say 40Hz is 10dBs less loud than say 60Hz, or the reverse.

As for the tools to accomplish this, it would certainly help to have a head unit or an external processor with enough equalizer bands to tune bass the way you like. I have Pioneer DEH-80PRS head unit, and it has bands at 20,30,50,80Hz, which is almost perfect for this. A slightly more coarse tuning device would an an amplifier with parametric bass boost. For example, the Soundstream Reference subwoofer amplifiers have it.

There is a different school of thought that says that the _box_ should be tailored to your car's acoustics. This way, you don't need to tune anything. I think this approach is a bit coarse as you can correct many things with DSP, and the tailored is useless if you need to move it to a different vehicle. For example, check out pwk designs web site. He sells box designs, and also complete boxes tailored to a car's acoustics.


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## Danometal (Nov 16, 2009)

I like super low tuning to cut out peaks and make the bass sound relatively flat all the way down. My box is 2.5 cubes @ 25 hz, and it sounds mostly flat from about 80 hz down to wherever.

I have always had trouble getting sealed boxes to sound flat, even with cabin gain helping the lows, maybe due to our lowered hearing sensitivity to lower frequencies.


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## rovertnamrod (Dec 6, 2012)

ZAKOH said:


> How did you measure that? Normally human ear is not sensitive in lowest frequencies. 30Hz and below is mostly felt than heard. 20Hz is pretty much not heard at all. When I want to break in a subwoofer I play a 20Hz test tone because no one can hear it. If you would like to get a precise measurement, you need a special measurement microphone, software, etc. Parts-express is selling calibrated Dayton audio microphones. There is one with a built in interface that you can plug directly into a laptop. Granted, a truly flat frequency response probably should not be the goal. Most people don't like how it sounds and prefer bass to be a little louder. You do have a problem when say 40Hz is 10dBs less loud than say 60Hz, or the reverse.
> 
> As for the tools to accomplish this, it would certainly help to have a head unit or an external processor with enough equalizer bands to tune bass the way you like. I have Pioneer DEH-80PRS head unit, and it has bands at 20,30,50,80Hz, which is almost perfect for this. A slightly more coarse tuning device would an an amplifier with parametric bass boost. For example, the Soundstream Reference subwoofer amplifiers have it.
> 
> There is a different school of thought that says that the _box_ should be tailored to your car's acoustics. This way, you don't need to tune anything. I think this approach is a bit coarse as you can correct many things with DSP, and the tailored is useless if you need to move it to a different vehicle. For example, check out pwk designs web site. He sells box designs, and also complete boxes tailored to a car's acoustics.


I didn't actually measure it. It is unnecessary to measure it because it is quite noticeable. Playing identical songs on other audio systems for comparison show that my sub sounds kind of weak compared to others when the notes get lower. It just needs more oomph on the low notes. And, it's not even super low notes like 25hz or lower, it's notes that are often used in songs, typically. It's just that i would like the lower notes of those songs to be as loud as the higher notes, thats all.


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## rovertnamrod (Dec 6, 2012)

cajunner said:


> parametric equalization?
> 
> the problem is usually attributed to a too small box. Not enough enclosure volume.
> 
> ...


My box is actually bigger than the manufacturers recommendation so that can't be the problem. And I have a Honda civic coupe.


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## Ray21 (Oct 19, 2009)

rovertnamrod said:


> I didn't actually measure it. It is unnecessary to measure it because it is quite noticeable.


I recommend you find a way to measure what you have and go from there. 

I've have the most luck with ported enclosures when trying to achieve more low bass.


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## axiom26 (Apr 21, 2010)

Has anyone tried the Anti Mode 8033 Auto Subwoofer EQ in the car yet? Has a 12v adaptor for car use. Seems like Hometheater forums like AVS rave about how nice it does with flat freq response and improved ringing. 

SimpliFi Audio - room correction
SimpliFi Audio - DSPeaker Store


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## boogeyman (Jul 1, 2008)

Measure transfer function of vehicle
design and construct an enclosure the exact opposite of transfer function
DSP to touch up


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## rovertnamrod (Dec 6, 2012)

ZAKOH said:


> As for the tools to accomplish this, it would certainly help to have a head unit or an external processor with enough equalizer bands to tune bass the way you like. I have Pioneer DEH-80PRS head unit, and it has bands at 20,30,50,80Hz, which is almost perfect for this.


Is it better to have a 16 band graphic equalizer like the Pioneer DEH-80PRS has or a 7, 5, or 3 band parametric equalizer? My headunit (Kenwood KDC x796) has a 3 band parametric eq but has bands at 60, 80, 100, and 200hz.


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## ZAKOH (Nov 26, 2010)

rovertnamrod said:


> Is it better to have a 16 band graphic equalizer like the Pioneer DEH-80PRS has or a 7, 5, or 3 band parametric equalizer? My headunit (Kenwood KDC x796) has a 3 band parametric eq but has bands at 60, 80, 100, and 200hz.


One simple thing you can try to do is get a bunch of test tones on a CD or USB key, 30Hz, 40Hz, etc in 10Hz increments up to 100Hz, and then play them all and hear if they're in accord with each other. Like I said, if you tune the system to "sound" flat to you, then you end up with a rising frequency response the lower frequency you go, but a lot of good sounding demo cars have been setup this way. This is certainly worth trying IMO. Parametric bands could be helpful if you need to boost or cut frequencies below 60Hz.

Another thing you can try to boost low frequencies is to use a sharper crossover. For example a lot of people use high pass at something like around 80Hz. Instead of doing that, try 50Hz or 60Hz LP with an 12dB or 18dB slope. This does not mean you won't get any subwoofer output at say 80Hz. You will get output there since the filter decays at 18dB per octave. But what you can now do is increase subwoofer output a bit, which effectively amounts to a boost of all frequencies at say 50Hz and below while leaving others to sound roughly the way they were with an 80Hz LP filter. No matter what I try, I always keep coming back to 60Hz LP with 18dB slope. This results in the most transparent and well behaved bass that sounds decent with a great variety of records. Other settings (specially higher LP freqs) sound great on some albums but harsh and unbalanced with drums on others due to the way things were recorded.


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## thehatedguy (May 4, 2007)

For the price of that, you could buy a processor that would allow you to do a whole lot more- XOs, delays, and EQing.




axiom26 said:


> Has anyone tried the Anti Mode 8033 Auto Subwoofer EQ in the car yet? Has a 12v adaptor for car use. Seems like Hometheater forums like AVS rave about how nice it does with flat freq response and improved ringing.
> 
> SimpliFi Audio - room correction
> SimpliFi Audio - DSPeaker Store


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## axiom26 (Apr 21, 2010)

I may end up trying it out if I can find a decent priced used one. New its $398 plus another $100 for the car adaptor. The good thing about it is all you got to do is set the mic up in the driver seat at ear level, run the test and your done, flat response, drastically improved decay times (tight sound). 

I guess no such thing as a free lunch, easy and quick = $


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## cruzinbill (Jul 15, 2011)

axiom26 said:


> I may end up trying it out if I can find a decent priced used one. New its $398 plus another $100 for the car adaptor. The good thing about it is all you got to do is set the mic up in the driver seat at ear level, run the test and your done, flat response, drastically improved decay times (tight sound).
> 
> I guess no such thing as a free lunch, easy and quick = $


or just get a 360.3..... which you can find around that price all day long.


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## axiom26 (Apr 21, 2010)

Much more complicated than the Anti-Mode 8033. Hook rca's up to anti mode then amp, attact microphone to camera tri pod, flip the switch to flat, lift 25, lift 35, run the test tones (no pc or phone required), unplug mic, leave Anti-mode on. Done. For Hometheater a friend used one and it took about 4 mins and decay times was drastically improved, boomy peaks were gone. 

Maybe in a couple of months, i'll try it out and post some results. I was just curious to see if anyone tried it in a car setup for subwoofers.


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## Spyke (Apr 20, 2012)

rovertnamrod said:


> What is the best way to have all the frequencies that a subwoofer plays output at the same volume. I have an Arc12d2 v2 and it gets quiet on the low frequencies. I would like those lows to be as loud as the rest of the frequencies. I would like to quiet the louder higher frequencies to match the loudness of the lower frequencies, rather than boosting the lower frequencies to match the loudness of the higher frequencies.


I didn't read any of the other posts but I had this same problem. Cross lower, steeper, and turn the sub level up. That's it. Try [email protected] or 24.


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## FG79 (Jun 30, 2008)

rovertnamrod said:


> What is the best way to have all the frequencies that a subwoofer plays output at the same volume. I have an Arc12d2 v2 and it gets quiet on the low frequencies. I would like those lows to be as loud as the rest of the frequencies. I would like to quiet the louder higher frequencies to match the loudness of the lower frequencies, rather than boosting the lower frequencies to match the loudness of the higher frequencies.


Desiring a flat response from a sub or system in general is more a theoretical fantasy than reality -- flat response is not ideal (notice I didn't say bad).

A good OEM car system is a great example of a flat response.

With respect to your question, I find that going with a lower Q system is the way to go (especially if you can fortify your system with strong midbass from your up front woofers). This, or a larger ported box tuned low would yield what you want. 

Personally I'm not a fan of just *1* sub, regardless of size or enclosure but to each their own. 

In practice, the ideal way to go in life is to build your boxes on the drier side of things, and use more drivers to compensate for upper bass SPL. The problem with high Q boxes is not only the loss of deep bass but the constant overwhelming attack regardless of the music type. With a more damped system, it only "hits" when the music asks it too. 

Four 8s, 10s, or 12s in low Q enclosures will give you everything you want. Refined bass and violence when needed. 

Truthfully, unless you're a real bass head, 1 or 2 subs will suffice. I recommend you go for a Q of 0.5 - 0.6 and if still not damp enough, stuff with polyfill (about 1/2 a pound to a pound per cubic foot of enclosure volume). 

A good sounding ported for a single 12" will probably be between 3-5 cubic feet. A big box indeed but worth it if done right.

EDIT: In re-reading your post, I'm not sure if I answered your Q. From my experience, it's best to to try and get the 80-150 hz midbass from your woofers, and 80 on down from the sub. If you do your midbasses right, your sub won't be asked to do a whole lot. In that case you have to focus on making the midbass work.....door install, amplifier, tuning, etc will be key. Pair it with an enclosure as described above and you will be on your own way to great refined bass.


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## ZAKOH (Nov 26, 2010)

Spyke said:


> I didn't read any of the other posts but I had this same problem. Cross lower, steeper, and turn the sub level up. That's it. Try [email protected] or 24.


This would probably only work if one has massive 6x9 or 8 inch midbass woofer in front. Otherwise, this will almost certainly kill the kick drum punch. 50Hz at 18dB already sounds off to me in my car sometimes. Either use a higher LP frequency or a less sharp slope. Once someone recommended using something like a 30Hz LP at 6dB. Unfortunately, I don't have the choice of 6dB slope to try this.


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## Spyke (Apr 20, 2012)

ZAKOH said:


> This would probably only work if one has massive 6x9 or 8 inch midbass woofer in front. Otherwise, this will almost certainly kill the kick drum punch. 50Hz at 18dB already sounds off to me in my car sometimes. Either use a higher LP frequency or a less sharp slope. Once someone recommended using something like a 30Hz LP at 6dB. Unfortunately, I don't have the choice of 6dB slope to try this.


Why would you need large midbasses? This is what people consistently fail to understand. You are basically flattening your response by crossing like this. You aren't adding a huge peak that needs giant midbasses to keep up with. Look at a response graph for a sealed sub. See how rolled off the output is? Now imagine a line representing the xo at 40hz. You have rising output and efficiency in the 40-50hz range in most sealed alignments, usually with a peak around 80-100. This is why people have this problem when crossing at the "standard" 80hz. Also, you don't need to cross the midbasses that low. Just keep them where they are comfortable.

I have a 12" sub with a Qtc of around .8 and 5" midbasses. Believe me, there is zero lack of punch or deep bass.


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## rich20730 (Feb 13, 2012)

Infinite baffle


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## hunde (Nov 14, 2008)

I just picked up an http://www.dspeaker.com/en/products/20-dual-core.shtml and in rough setup has taken my home system to new levels of cohesion and linearity i've never come close to. I can't wait to try it in my car...

Tom


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## sqnut (Dec 24, 2009)

rovertnamrod said:


> What is the best way to have all the frequencies that a subwoofer plays output at the same volume. I have an Arc12d2 v2 and it gets quiet on the low frequencies. I would like those lows to be as loud as the rest of the frequencies. I would like to quiet the louder higher frequencies to match the loudness of the lower frequencies, rather than boosting the lower frequencies to match the loudness of the higher frequencies.


You don't want all the frequencies the sub plays to be at the same volume, if you set it up like that, you'd find the 30-60hz range lacking.









You want a roll off from 20-80 or to wherever you're playing the sub.


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## SkizeR (Apr 19, 2011)

sqnut said:


> You don't want all the frequencies the sub plays to be at the same volume, if you set it up like that, you'd find the 30-60hz range lacking.
> 
> 
> 
> ...


thread is over 2 years old


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## sqnut (Dec 24, 2009)

SkizeR said:


> thread is over 2 years old


damn the thread bumping :blush:


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## gstokes (Apr 20, 2014)

boogeyman said:


> Measure transfer function of vehicle
> design and construct an enclosure the exact opposite of transfer function
> DSP to touch up


The Subwoofer DIY Page: Measuring a car's transfer function


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## brandonyuen (Oct 26, 2017)

I know this is an old thread, but I just wanted to post that I tried the anti-mode 8033C in my car and it was great! I could turn the bass up without hearing that single overpowering note (kinda like an imprecise thud + pressure wave) that seems to happen a split-second after the actual bass note. I'm not sure what it was, but I've heard it in pretty much every car with a subwoofer. 

Too bad I don't have the car adapter (yet) though... so I eventually had to unplug the anti-mode from the wall and drive off. 

I think the newer models take 12V dc, so I'm in the market for one of those.


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