# Should I use a High Pass filter even without a sub?



## Mohito (Mar 7, 2011)

Hello,
I have a pair of Morel Hybrid 602's up front (connected to a Sinfoni Tempo Presto), and was told I should set up a High Pass filter (at 62Hz? that's what my HU allows). Presumably it should improve the sound quality?

But these speakers go down to 50Hz and turning on the HPF makes the bass sound lacking... I don't have a sub yet and unlikely to have for a while...

Please do share your thoughts,
Thanks!


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

Without it you risk killing them, depending on your listening volumes and musical taste.

You would also be running it through fs, which means lots of distortion.


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## Mohito (Mar 7, 2011)

TOOSTUBBORN2FAIL said:


> Without it you risk killing them, depending on your listening volumes and musical taste.
> 
> You would also be running it through fs, which means lots of distortion.


Thanks Mate,
But shouldn't the crossovers on the speakers protect them? I'm not running high volumes, about 40% of capacity.

Also, what is FS?

Thanks mate!


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## BTA (Nov 5, 2005)

The passive crossover on the mid is only cutting off the higher frequencies, probably 3k or 5k and up.

If you run without a HPF your mids will be playing down into the sub region and beyond. Which they can't really play anyway, but they'll try, and that can be problematic. You are basically over-working your mids for no gain.

You may be okay with a HPF around 40 or 50hz though if you want to give it a try. Just see how low you can go before distortion kicks in, I'm going to guess around 50hz. 

I wouldn't run without the HPF at all though.


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

Fs is the resonant frequency of the driver. It can be found in the specs. Its basically the frequency where there is the least control of the cone, due to the weight of the moving mass being in tune with the stiffness of the suspension. This always results in a big peak in distortion. The fs of your speakers is 45hz. Playing anywhere near that will mean playing through that peak in distortion.


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## syc0path (Jan 23, 2013)

Slightly distorted bass is better than no bass at all. And keep in mind that a full-range speaker system is just that -- it can play full-range at its rated power. It may not sound good doing it, but it's not going to blow up.


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## Mohito (Mar 7, 2011)

TOOSTUBBORN2FAIL said:


> Fs is the resonant frequency of the driver. It can be found in the specs. Its basically the frequency where there is the least control of the cone, due to the weight of the moving mass being in tune with the stiffness of the suspension. This always results in a big peak in distortion. The fs of your speakers is 45hz. Playing anywhere near that will mean playing through that peak in distortion.


Thanks,
I'm a bit cofused, because the Morel Hybrid 602 have a frequency response range of 50-25000 on the site ( Hybrid 2-way « Morel ) - but if you look at the specs sheet the woofer can go down to 35Hz? http://www.morelhifi.com/wp-content/uploads/2012/05/Hybrid-modified-spec.pdf

In any case, I understand I need to avoid the 45Hz frequency - but my head unit can only do HPF at 62Hz - are those 12Hz going to be missed? I have to say I haven't heard any major distortions...

PS
Why don't we use HPF with 'proper' stereo stand mounts speakers?

Thanks,


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## minbari (Mar 3, 2011)

Mohito said:


> Hello,
> I have a pair of Morel Hybrid 602's up front (connected to a Sinfoni Tempo Presto), and was told I should set up a High Pass filter (at 62Hz? that's what my HU allows). Presumably it should improve the sound quality?
> 
> But these speakers go down to 50Hz and turning on the HPF makes the bass sound lacking... I don't have a sub yet and unlikely to have for a while...
> ...


really depends on the speakers. I know with my x65 on HU power. didnt matter if I used an HPF or not. with only 18 watts of power, I couldnt hurt them if I tried.

if you have a real amount of power, then yes, most definately use one or you will kill em. remember for every octave you go down, excursion goes up 4x


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## Viggen (May 2, 2011)

I see no need to cut the bass out of those speaker. Eliminating the low frequencies like stated you will loose a bit of music

There is nothing wrong with letting your speakers play all frequencies, as stated you just have to be careful with the volume which it sounds like you are. Many home speakers and oem car stereo setup have speakers which are not subwoofers and play all frequencies.

Manufacturers state the frequency response with a +/- 3 db rating so the 50-25k hz is just that, +/- 3db. And speaker will play higher as well as lower frequencies however it will fall outside of the +/-3db range. Could be a 6db drop at 35hz


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

The rated power spec is most likely a thermal rating, not a mechanical rating with no low pass. With 140 watts, they will absolutely bottom out if played full range in a door, they only have 3.5mm of excursion.


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## minbari (Mar 3, 2011)

Viggen said:


> I see no need to cut the bass out of those speaker. Eliminating the low frequencies like stated you will loose a bit of music
> 
> There is nothing wrong with letting your speakers play all frequencies, as stated you just have to be careful with the volume which it sounds like you are. Many home speakers and oem car stereo setup have speakers which are not subwoofers and play all frequencies.
> 
> Manufacturers state the frequency response with a +/- 3 db rating so the 50-25k hz is just that, +/- 3db. And speaker will play higher as well as lower frequencies however it will fall outside of the +/-3db range. Could be a 6db drop at 35hz


as mentioned above, most OEM full rage speakers dont have alot of power on them. 20 watts at most. with no HPF you will kill them. a 6.5" isnt going to produce anything below 60hz with any real authority anyway, so you are missing anything, except distortion.


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## Hanatsu (Nov 9, 2010)

Place a HPF at 50-60Hz, it's an invitation to distortion to run them fullrange down.


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## TrickyRicky (Apr 5, 2009)

Viggen said:


> I see no need to cut the bass out of those speaker. Eliminating the low frequencies like stated you will loose a bit of music
> 
> There is nothing wrong with letting your speakers play all frequencies, as stated you just have to be careful with the volume which it sounds like you are. Many home speakers and oem car stereo setup have speakers which are not subwoofers and play all frequencies.
> 
> Manufacturers state the frequency response with a +/- 3 db rating so the 50-25k hz is just that, +/- 3db. And speaker will play higher as well as lower frequencies however it will fall outside of the +/-3db range. Could be a 6db drop at 35hz


OEM speakers are powered by OEM radios.... OEM radios have very low output on the low fhz side. Thats to keep the OEM speakers safe.


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## Mohito (Mar 7, 2011)

I mean normal 'home' Hifi floor standers speakers are run at full range and most stereo amp won't even have an HPF...?


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

That doesn't mean that's how they sound best. And most home floor standers are much more capable than the morels you are currently using.


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## BTA (Nov 5, 2005)

Gotta love people who ask for help and then argue with you. Run them with no hpf if you are so inclined then.


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## TrickyRicky (Apr 5, 2009)

BTA said:


> Gotta love people who ask for help and then argue with you. Run them with no hpf if you are so inclined then.


He has to understand that home audio set up don't usually have the HPF option because they have passive xovers. 


OP, give them full range and their rated power...Good luck.


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## Mohito (Mar 7, 2011)

Hang on guys,
My speakers do have passive crossovers...
HYBRID 2-way / Integra « Morel

And as mentioned, I never go above 40% volume, this is an SQ set up... ;-)

OK, 
If I have to set up a HPF where should I do it? In the HU or the amp? the HU can do 62HZ and the amp is less clear as its an 'analogue screw' to rotate so hard to be exact...

I do appreciate the help and feedback!


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## SPLEclipse (Aug 17, 2012)

Almost all "hifi" floorstanding towers are crossed over, usually through the preamp/processor. The Dolby standard is an 80hz crossover point for example.

You can leave the high-pass off it you want. If it sounds better then do it. Just be aware it only takes one moment of heavy peaks in the lower octaves to kill them for good. It's not something I personally would risk. Doesn't the Sinfoni have a HP filter? Bypass the headunit HP and use the one on the amp if you feel the need to fine tune it more. At least there will be some measure of protection from frequencies that are sub-sonic or inaudible.


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## FG79 (Jun 30, 2008)

BTA said:


> Gotta love people who ask for help and then argue with you. Run them with no hpf if you are so inclined then.


I normally don't like that mentality of asking questions just to verify what you want to hear.

However, the OP is not off base in this matter as far as the reality of the situation.

I've mentioned numerous times before with the right size door, door install and amplifier you can absolutely run a system full range. And without subs too. It was the only bass I had in the car for a few months while I got my amps repaired. 

Will you be limited in how much you can pound? Yes. 

The idea that the minute you go without an HPF your speakers will distort all over the place at low to medium volumes is BS, assuming you have the right gear and setup. 

On certain songs/tracks, the full range sound is qualitatively better than the typical high pass. I remember the sound of electric bass on a good recording just having a certain presence that it didn't have with an HPF AND subs. 

The better the recording, the more you can get away with this setup. If all you listen to is heavily limited/compressed crap, it will suck (but it's not much better with an HPF). Going with a very high HPF (like 100-120hz+) can solve the issues of s*** recordings, but ruins it for everything else. 

It's one of those things that you have to EXPERIENCE to believe. Unfortunately I don't think any DIY guys ever got to hear my car during this state. 

And yes, home audio speakers can handle the low frequencies. More so because of enclosures (vented mostly) than the idea of being "better quality", which is not always the case. 

A 6.5"-8" door woofer cannot reproduce the very deep bass of a sub, so you can't expect miracles. However, it can produce the 70-100 hz in spades, which is the heart of most music. 

If I were to build a system for my parents, I would forego the HPF for sure. 

Always remember that the volume control is your best friend in all listening situations. As long as you are careful, you will be fine.


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## FG79 (Jun 30, 2008)

SPLEclipse said:


> *Almost all "hifi" floorstanding towers are crossed over, usually through the preamp/processor. *The Dolby standard is an 80hz crossover point for example.
> 
> You can leave the high-pass off it you want. If it sounds better then do it. Just be aware it only takes one moment of heavy peaks in the lower octaves to kill them for good. It's not something I personally would risk. Doesn't the Sinfoni have a HP filter? Bypass the headunit HP and use the one on the amp if you feel the need to fine tune it more. At least there will be some measure of protection from frequencies that are sub-sonic or inaudible.


That is not true.

Real home hi-fi do not use processors (there's no need).

The high end pre-amps/power amps I know do not have any crossovers built in whatsoever. The only crossovers are the passives in the speakers themselves, and they don't high pass the woofer.

This even applies to studio monitor/bookshelf speakers whose frequency response may only be down to 50-60 hz.

If you don't believe me, ask any of these hi-fi speaker manufacturers if they recommend an HPF.


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## Hanatsu (Nov 9, 2010)

FG79 said:


> 1.The idea that the minute you go without an HPF your speakers will distort all over the place at low to medium volumes is BS, assuming you have the right gear and setup.
> 
> 2. On certain songs/tracks, the full range sound is qualitatively better than the typical high pass. I remember the sound of electric bass on a good recording just having a certain presence that it didn't have with an HPF AND subs.


1. "Low/medium" means? Normal listening volumes lies around 85-90dB in the midrange, bass should be tuned 10-15dB above that. At that volume a 'generic' 6,5" WILL distort 'all over the place'. Excursion control is the only way to fix this, i.e HPF. 

2. So you like the presence of distortion... fine. Just don't call it "better".


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## Hanatsu (Nov 9, 2010)

FG79 said:


> That is not true.
> 
> Real home hi-fi do not use processors (there's no need).
> 
> ...


In home cinema setups (I think he refers to that) it's normal to use HP filters, or in HiFi setups with subs.


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## Mohito (Mar 7, 2011)

Thanks for all the advice people, 
I tried using the HPF at 62Hz (via the HU) and it does sound lacking.

My current amp is a temporary Genesis series 3 - four channel (2x75W) - will get the better Sinfony Adente (2x95W) later in the month. - The new amp has a subsonic filter which I'll be happy to use... still not sure about the HPF...

The car is a Jaguar S-Type (2000' model) - so has 'big doors'?
I never play more than 40% volume.

Please do share your thoughts.


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## SPLEclipse (Aug 17, 2012)

A subsonic filter is just a high pass filter that has a lower range than normal. Does the Genesis have a built in filter? What I was suggesting earlier is to use the amp's built in high pass instead of the headunit one since it seems that it is a little too high for your liking. Rather then take an "all or nothing" approach why not find an appropriate crossover point using the amp?


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## Mohito (Mar 7, 2011)

SPLEclipse said:


> A subsonic filter is just a high pass filter that has a lower range than normal. Does the Genesis have a built in filter? What I was suggesting earlier is to use the amp's built in high pass instead of the headunit one since it seems that it is a little too high for your liking. Rather then take an "all or nothing" approach why not find an appropriate crossover point using the amp?


Ok,
I set up a HPF on the amp at around 50Hz - I think - still sounds like full bass (compared to if I set a 62Hz HPF via the HU) - and hopefully I could now sleep in peace... ;-)

One last thing - I wonder if the HPF will influence the speakers burn in? They are being run now and I still didn't clock the required 40 hours...

Thanks for all the help!


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## Hanatsu (Nov 9, 2010)

If you wanna speed up burn in, just play fullrange pink noise near their rated Xmax for a day or two. Connect a battery charger and leave the stereo on over the night 

HPF at 50Hz sounds good.


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## amalmer71 (Feb 29, 2012)

That was actually a common fix when I worked at Best Buy for a few months during the holiday season. People would complain that there was a loud rattling noise coming from their speakers when they turned it up. Luckily many of the headunits sold were Pioneer and had a HPF and went as low as ~50Hz.

The problem wasn't the speakers. It was either their door panels or their rear dash, but removing the real low bass helped clear up the problem and it usually sounded better, too, because the speakers weren't trying to reproduce frequencies which they weren't really designed to produce efficiently. 

The features of the Pioneer headunits is actually a double edge sword. Pioneer has that "Superbass" feature which always gets set to max by people because they think it's cool, yet complain when the music sounds like crap. If I found the setting up that high I would just set the HPF to 63Hz.


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## 1fastkingcab (Nov 23, 2010)

FG79 said:


> That is not true.
> 
> Real home hi-fi do not use processors (there's no need).
> 
> ...


anything THX certified has HPF's @ 80hz with a 12db slope. every Home theater receiver i've worked with won't let you use any of the THX sound options unless the LFE output is active because with the LFE disabled the HPF is automatically disabled. also any Sony, Harmon Kardon, Denon & Pioneer receiver that asks you the speaker size during initial setup, even though the question is if the speakers are "Large" or "Small" the parameter that is being adjusted is the HPF frequency which is typically 63hz for large or 80hz for small. The only way to disable the HPF on most of them is to disable the LFE or Pioneer Elite units let you choose weather the LFE is a pure LFE or "Full" which is actualy a 80hz LPF and then also disables the HFP on the fronts if they are set to "Large" but like I said before seting it up like that will lock you out of THX, Dolby Pro Logic IIx and Dolby Pro Logic IIz


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## Alrojoca (Oct 5, 2012)

Also keep in mind, Loudness should be off when using an amplifier.

HU's HPF is pre amplified filtering, a passive crossover is a post amplified signal and more of a protection than a crossover.

The bass being heard or not heard has to do with the mid bass driver installation
and if the doors are deaden properly and inner door openings are closed and sealed as much as it is allowed since every door is different, that will make the mid bass tightness and real response play they way it should and be heard. Also when the doors are not sealed and have large openings, the driver can play almost like if it was in an IB set up trying to play lower frequencies and not really be able to play them. Therefore the filtering helps and with the door sealed as much as possible the bass just gets better.

Then use the EQ to reduce and equalize the sound for the best quality possible at the right volume level


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