# What freq should I crossover my sub?



## newport2002 (Oct 7, 2009)

I am going to be dialing in my system and I am curious as to what frequency to crossover my subwoofer. My system is Hertz HSK 165 components, Soundstream TN950.5 amp, and Alpine Type R 8" sub woofer. Currently I have the subwoofer crossed over at its highest frequency on the sub channel which is 220 Hz. I have rolled off a bit of the low frequencies from the Hertz Speakers. Is 220 too high for the sub? Not high enough?


----------



## Cruzer (Jul 16, 2010)

I think there is an old thread with a poll about where people have their sub crossed over at. I believe 63hz won the poll. I personally use 100hz

I don't think I've ever heard anyone using 220. I think The highest people usually use is 100-125hz


----------



## gijoe (Mar 25, 2008)

I go for 100-120hz. IT's still low enough to prevent localization (assuming you've taken care of the rattles in the back) but high enough to take some of the strain from the mids. I don't see the point of running any 6.5" down to 60hz, let the sub do the work down there.


----------



## gckless (Oct 11, 2012)

Most subs will fall off sharply above 100-ish hertz or even lower. Most. I know a lot of people here use higher quality drivers that are capable, but in general, it's not too far off. Besides that, you start to get localization and a bunch of stuff you don't want.

I cross at 63Hz. I would love to cross at 50Hz, but my mids can't deliver the output I want at this time.


----------



## newport2002 (Oct 7, 2009)

Thx guys. My amp does not have indicators on the adjustment so I have to ball park it. I think I'm in the 120-150 range. Sounds cleaner and less localization. Also I think I had the miss crossed over too high so I brought that down to about 150. System sounds cleaner to my ears now. I'll drive like this for a bit and see if I need anymore adjustments. This at least got me in the ball park.


----------



## YukonXL04 (Mar 6, 2014)

I usually set mine to 120ish for sealed boxes, and 80ish for ported. For me it seams a ported box crossed over that high usually has too much humming for my tastes. However it also depends on what type of music you listen to and what sounds best to you.


----------



## _Nomad_ (Dec 11, 2012)

I crossover the sub somewhere in the 70Hz to 80Hz range.


----------



## Airforceyooper (Sep 22, 2005)

I'm at 70hz right now I believe.


----------



## Cruzer (Jul 16, 2010)

U have your mids at 150? Interesting


----------



## newport2002 (Oct 7, 2009)

Cruzer said:


> U have your mids at 150? Interesting


I should be more clear. 2 way components run passive. High pass filter on the amp set at 150. That's going to the crossover then to the mid bass drivers and the tweeters. Low pass filter going to sub set about 150.


----------



## Airforceyooper (Sep 22, 2005)

You might consider dropping both of them down to about 80hz.


----------



## fcarpio (Apr 29, 2008)

It depends. On my previous system (3 way active with 8" midbass) I had the subs crossed over at 40Hz. My current system (two way active with 6.5" midbass) I have the sub crossed over at 80Hz.


----------



## newport2002 (Oct 7, 2009)

So I am probably still too high. Hmmm. Ok. I was filtering the bass so my hertz mid bass drivers wouldn't have to work so hard. I had both replaced under warranty. Didn't notice an issue with them until I got an amp and they both soon failed. At first I thought it was too much gain but now l think I was just pushing them way too hard with just the head unit and no amp.


----------



## miniSQ (Aug 4, 2009)

newport2002 said:


> So I am probably still too high. Hmmm. Ok. I was filtering the bass so my hertz mid bass drivers wouldn't have to work so hard. I had both replaced under warranty. Didn't notice an issue with them until I got an amp and they both soon failed. At first I thought it was too much gain but now l think I was just pushing them way too hard with just the head unit and no amp.


depending on how loud you listen, i think i would run the fronts HP's at about 85-100 and run the sub LP at 80. Both with 24db slopes...and then experiment with the sub at 12 and 24 and see if it changes...and then flip the phase on the sub and try both again...pick what sounds best to your ear.


----------



## tgotovac (Mar 25, 2014)

You should have no problem crossing those mids down to 80 or below if your gains are set properly and you don't abuse the volume control. My audison voce 6.5's are crossed at 63hz with a 18db slope being powered by a bridged JL HD 600/4 and I do listen very loud and haven't had a single issue yet mind you I did take time to set the gains nicely.


----------



## newport2002 (Oct 7, 2009)

Ok. Step 1 is to use a DMM and set the gains. Then should I use test tones at say 80 hz to tune adjust the crossover points since my amp doesn't have labeled adjustments?


----------



## tgotovac (Mar 25, 2014)

Does your headunit have any crossover options ? Or are you using a factory headunit ?


----------



## newport2002 (Oct 7, 2009)

It's a nakamichi cd500. 6 channels of separate outs but no crossovers.


----------



## tgotovac (Mar 25, 2014)

I don't know anything about that amp, but have you looked at the manual for it ? There might be something that shows you where to put the crossover knob to get a specific frequency. I know the JL HD amps have a section in the manual that shows you where to put the dial to get a specific frequency


----------



## momax_powers (Oct 26, 2013)

You could use a ddm to set the lp freq aswell...if you want to set it at 100hz set the lpf to minimum...play a 100hz tone and turn the lpf knob up slowly while watching the voltage....if amp uses a 12db BW slope, when the voltage goes down to half the initial voltage, then that would be 100hz (12db BW = -3db at xover point = half power)...if its a 24db LW filter then its 1/4 voltage at xover point (-6db)

also you dont need to have the volume too high when doing this


----------



## newport2002 (Oct 7, 2009)

momax_powers said:


> You could use a ddm to set the lp freq aswell...if you want to set it at 100hz set the lpf to minimum...play a 100hz tone and turn the lpf knob up slowly while watching the voltage....if amp uses a 12db BW slope, when the voltage goes down to half the initial voltage, then that would be 100hz (12db BW = -3db at xover point = half power)...if its a 24db LW filter then its 1/4 voltage at xover point (-6db)
> 
> also you dont need to have the volume too high when doing this


perfect! I'll set those things now…its a 12db slope.


----------



## newport2002 (Oct 7, 2009)

Update...bought a DMM and set the gains by it. The sub channel was a little hot and the front channels were low. So I set them accordingly. I set the gains low on the sub channel. The amp puts out 430 at 2 ohms. The sub has an RMS of 350 watts. So I set it at 350. Then I adjusted from there. Oh I set the crossover at 100hz with the DMM. Sub sounds great but I think I will lower the crossover point for the fronts. They are not working hard at all. I will live with it a few days before making any more adjustments. This is the best it's sounded so far! Balanced is the word I would use. And it sounds great on nearly nearly everything without adjustments. Before I was adjusting sub level and eq for nearly every song. Now everything sounds great and when turned up its nice and clear and clean with plenty of punch down low. Thanks everyone for the advice on dialing this in!!!!


----------



## sqnut (Dec 24, 2009)

Your mids should carry 80% of the low end. The sub only fills in the balance 20% below ~50hz. Try crossing the sub and mid ~60hz. That's the sweet spot in most cases. Put your sub on steep slopes (min 4th order). Front to back localisation starts above ~70hz.


----------



## diy.phil (May 23, 2011)

Maybe something like this...
8" 100 Hz
10" 80 Hz
12" 70 Hz
13.5" 63 Hz
15" 60 Hz
20" 50 Hz


----------



## LaserSVT (Feb 1, 2009)

I am currently at 63hz with 36db slopes.


----------



## newport2002 (Oct 7, 2009)

Im stuck with 12db slopes unfortunately. I don't plan on buying any more audio equipment and thats what my amp has on it.


----------



## Kane (Mar 3, 2009)

dont want to hi jack this thread but how are you getting 24 and 36 db slopes?


----------



## diy.phil (May 23, 2011)

some DSPs have 24 db/o slope. plus 12 on the amp = 36 hmmm... ?


----------



## LaserSVT (Feb 1, 2009)

My deck has the option of up to 36db slopes but I am not running it in that mode. In its current mode it can run up to 18db but I have its high and low at 12db and the amps have a 24db (also selectable) and in this combo the stereo has the best tonality. No phase changes were required.


----------

