40Hz filter

[steve_1979]

I've been wondering if it's possible to give the DM5's a little extra dynamic range at high volume levels by filtering the sub bass below 40Hz. As the DM5's don't have any bass below 50Hz filtering everything below 40Hz shouldn't make any difference to the sound at normal listening levels but at high volume it would make life a little easier for them.

My Yamaha AVR doesn't have any functions which would allow me to try this so I was wondering if there's any sub filter that can be fitted between the Yamaha's pre-outs and the DM5's.

Can anyone recommend a product that can perform this task and is it likely to make enough difference to be worth the hassle?

 

[steve_1979]

Of course the subwoofer would be unaffected by this filter as it has its own subwoofer pre-out socket from the Yamaha separate to the left/right pre-outs that drive the DM5's.

 

[Vladimir]

I've tried this with various speakers, with DSP on my PC and analogue EQ component. The DM5s do have bass under 50Hz but not at -+3dB, of course. If you cut it off with a shelf filter the speakers will have less distortion and the amplifier will have an easier task driving them. However, you may notice some harmonics missing as high as 100Hz, especially on good recordings of live instruments.

 

[steve_1979]

I've tried this with various speakers, with DSP on my PC and analogue EQ component. The DM5s do have bass under 50Hz but not at -+3dB, of course. If you cut it off with a shelf filter the speakers will have less distortion and the amplifier will have an easier task driving them. However, you may notice some harmonics missing as high as 100Hz, especially on good recordings of live instruments.

I hadn't considered that. Ah well I guess that knocks that idea on the head. It was just something that I'd been wondering about.

I doubt that it would have made much (if any) difference anyway. The DM5's go pretty loud and there aren't any signs of reduced dynamic range or the soft clipping kicking in at the volume levels I usually listen at anyway.

 

[lindsayt]

Steve have you ever measured the SPL's in db's at your listening position and at 1 metre with a calibrated sound meter?

 

[Overdose]

I've tried this with various speakers, with DSP on my PC and analogue EQ component. The DM5s do have bass under 50Hz but not at -+3dB, of course. If you cut it off with a shelf filter the speakers will have less distortion and the amplifier will have an easier task driving them. However, you may notice some harmonics missing as high as 100Hz, especially on good recordings of live instruments.

Whilst it is true that harmonics exist up and down the entire spectrum of frequencies, they are inherent in the recording and so would not be affected by the removal of the fundamental frequency at the replay stage. The filter would merely cut off all above or below the set point.

What would happen however, is that any resonance in the speakers related to the frequencies affected by the cut off would be eliminated, as they are caused directly by those now removed frequencies and that would only be a good thing.

@ steve_1979, If you have noticed that you need more headroom, then really, you need different speakers that are up to the task. As good as the DM5s may be, you might have found their limit if you feel the need for more dynamic range.

 

[steve_1979]

Steve have you ever measured the SPL's in db's at your listening position and at 1 metre with a calibrated sound meter?

No.

 

[Vladimir]

Steve is just having fun tweaking, which is something I do also because it's fun. We don't have to buy new gear everytime our brain dynamic range becomes insuficient (OCD). *biggrin*

Whilst it is true that harmonics exist up and down the entire spectrum of frequencies, they are inherent in the recording and so would not be affected by the removal of the fundamental frequency at the replay stage. The filter would merely cut off all above or below the set point.

I wasn't implying one can remove harmonics from the recording but by reducing their core originating frequency they are being reduced in dB upwards, which effectively to my hearing sounded slightly unatural deviation from an instruments timbre I knew existed there on other speakers and headphones. Obviosly this is something I did with my reference records, which I've played for years to test and roughly calibrate my gear.

What would happen however, is that any resonance in the speakers related to the frequencies affected by the cut off would be eliminated, as they are caused directly by those now removed frequencies and that would only be a good thing.

Indeed, posible cabinet resonances, ports and drivers distorting/ringing can be reduced with adding up another shelf filter over the one the manufacturer used in these actives. However that makes the assumption those issues pre-exist and we are now bettering the speaker. But what if there aren't any? Then we might be making the original well sorted out design slightly worse. The speakers are voiced also by ear for their color/tone/timbre and by reducing the lower frequency originating harmonics we are changing it and revoicing the speakers.

This is something like removing the grills on speakers that were designed to have them on while playing music. If the manufacturer designed them to be on or off, this will be indicated in the manual and/or the brochures for the owner. If the grills are transparent and don't make an audible difference, there won't be any instructions for the owner.

Why not ask AVI directly if this is a good idea? Shoot them an email Steve.

 

[Vladimir]

The DM5's are plenty loud enough for my needs 99.9% of the time as I only sit 1.5 meters away from them. It's just those very rare occasions when I really want to whack the volume up high and I'm not at my desk I wonder if the DM5's soft clipping may be starting to have an impact on the dynamic range.

Does the soft clipping controller switch the signal through fixed discrete circuitry (set of resistors, caps, chokes etc.) or is it done variably with an opamp depending on the amount of excessive load?

The fact it has a soft clipping circuitry means there is a point where they can be overdriven. This is a smart decision from the manufacturer because 9 out of 10 will come back as damaged eventually under warranty. Reasons, their owner deciding they are no longer desktop speakers and he wants to disco boogie now. *biggrin*

 

[Vladimir]

As I have explained numerous times, if EQ circuits are used to obtain a very flat response , they will interfere with phase and sound worse than speakers like ours that may have a less even amplitude response, but far more perfect phase one.

Source

HDD Audio forum? Unless you play from a hard drive, you can't be a member? *scratch_one-s_head* Or is it HD Digital Audio...? Well it has AJ's comment regarding applying EQ.

 

[steve_1979]

Why not ask AVI directly if this is a good idea? Shoot them an email Steve.

I started an identical thread on the AVI forum and the general consensus is that at 40Hz it wouldn't make enough difference to be worth doing.

 

[steve_1979]

Does the soft clipping controller switch the signal through fixed discrete circuitry (set of resistors, caps, chokes etc.) or is it done variably with an opamp depending on the amount of excessive load?

I don't know but I would guess it's the latter. This is the quote from the AVI website:

"Built-in AVI Intelligent Monitoring System examines the music and momentarily reduces gain to combat peaks that might cause clipping."

 

[steve_1979]

HDD Audio forum? Unless you play from a hard drive, you can't be a member? *scratch_one-s_head* Or is it HD Digital Audio...?

The forum started off several years ago as a computer audio forum hence the HDD Audio name. Even from the beginning it's always had a strong pro AVI bias. It's always been very pro science/objectivist in nature and anti audiophool foo in all its forms.

The previous forum moderator didn't have enough spare time to keep up with all the necessary work involved with running a forum so a few years ago it was passed onto Ashley James to officially become the AVI forum.

 

[Vladimir]

Ahh... Well, manufacturer forums generally bore me after a week, regardless of their paradigm of thinking. I practice Hi-Fi polygamy.

 

[lindsayt]

Who was the previous HDD forum moderator?

 

[fr0g]

Who was the previous HDD forum moderator?

Darren

 

[fr0g]

Ahh... Well, manufacturer forums generally bore me after a week, regardless of their paradigm of thinking. I practice Hi-Fi polygamy.

Agreed. Forums such as this one, whilst full of loonies, are "allowed" to be full of loonies.

Big difference and a welcome lack of thought police.

 

[steve_1979]

@ steve_1979, If you have noticed that you need more headroom, then really, you need different speakers that are up to the task. As good as the DM5s may be, you might have found their limit if you feel the need for more dynamic range.

The DM5's are plenty loud enough for my needs 99.9% of the time as I only sit 1.5 meters away from them. It's just those very rare occasions when I really want to whack the volume up high and I'm not at my desk I wonder if the DM5's soft clipping may be starting to have an impact on the dynamic range.

I did accidentally run them at maximum volume for several seconds once (I hadn't realised the RCA sockets on the Behringer DAC have a fix output). They do go very loud for their size and thanks the soft clipping they also sound remarkably undistorted when pushed past their limits.

I currently run the DM5's full range as I think they have the best sound quality when setup this way. I've also tried them crossed over to the sub at 60, 80 and 100Hz and TBH the difference in both the dynamic range (slightly better) and overall sound quality (slightly worse) is very small. Hardly even noticeable.

I doubt that I need any more dynamic range but would like to try out a 40Hz filter just to see what difference it does make (though it will probably be too little to be noticeable with the filter set so low at 40Hz).

 

[kingsap]

I need a 40hz filter too. Is there anyone to mention how this could be done? My speakers reach 28hz and my sub cross over at 40 hz. How can we cut the frequency of the speaker so i can blend it nicer with the sub?

The sub is connected by preout of the preamp

 

[fr0g]

I need a 40hz filter too. Is there anyone to mention how this could be done? My speakers reach 28hz and my sub cross over at 40 hz. How can we cut the frequency of the speaker so i can blend it nicer with the sub?

The sub is connected by preout of the preamp

I can't vouch for its quality, but I think the miniDSP will do this. I looked into it last year but didn't end up going for it...

http://www.minidsp.com/applications/digital-crossovers/subwoofer-integration-with-minidsp