Is a high pass filter necessary for my setup?

[girtab]

I had a minidsp SHD, bought in their Webshop and directly imported from Hong Kong to Germany. There was an issue with the PSU and minidsp immediately sent a replacement PSU. I have nothing to complain.

As you see in my signature I own a ADI-2 Pro Fs R as well. The ADI units have only very limited PEQ capability (number of PEQ, max Q, max cut, frequency resolution), not sufficient for bass EQ, and no flexible high/low pass filters. Also no capability to set delays. They are a moly not designed to be used as loudspeaker controllers.

A miniDSP SHD or Flex would offer you all the basic functionality you require at a relatively reasonable cost. If course without detailed level displays, without loudness, without bass/treble control...

what is the maximum cut for the filters? Knowing RME the limits are probably there for a good reason like max Q.

I've heard lots of complaints from people regarding minidsp support, saying they got ghosted and such.. Also import fees, potential replacement shipping costs and such things draw me away from minidsp. Also I prefer to tweak things straight from the device instead of using a GUI

 

[markstein]

Hello everyone, I'm deciding between an RME ADI-2 DAC (€~1k) and ADI-2/4 Pro (€~2.5k). The 2/4 would let me properly high-pass the mains (big floorstanders) and low-pass the subs, while the cheaper DAC would mean running the mains full-range and only low-passing the subs.

My goal is maximum SPL with the smoothest bass possible across multiple listening positions and potentially extend the LF extension to infrasonics. My mains also reach flat down to 25hz in my room with no EQ. (Though I do cut a huge low Q room mode at 50hz by i think -14db because of wall proximity)

Is it generally better to:

1. Run mains full-range + low-pass subs, using multiple bass sources to help excite room modes more evenly, or
2. High-pass mains + low-pass subs, sacrificing some distributed bass sources for crossover control?

I can't audition both setups, so I'm trying to decide which hardware makes more sense. Obviously I'm also more inclined to get the Adi-2 DAC as the 2/4 is more targeted towards professionals and has features/inputs which I wouldn't use.

Any response would be greatly appreciated!

In my setup, I also tried the Geddes approach (mains full range, subs low passed) but did not manage to integrate them properly, due to phase mismatch in overlapping frequency range. I would always low pass a ba and high pass mains or - even better - use Dirac ART which works really very well!

 

[girtab]

In my setup, I also tried the Geddes approach (mains full range, subs low passed) but did not manage to integrate them properly, due to phase mismatch in overlapping frequency range. I would always low pass a ba and high pass mains or - even better - use Dirac ART which works really very well!

Thanks this is actually very helpful. Seems like the geddes approach really might be compromised.

 

[Flaesh]

I use a separate subwoofer band (see signature) and bass-less mains, made specifically for this purpose. The crossover is around 80+ Hz.

 

[markstein]

Thanks this is actually very helpful. Seems like the geddes approach really might be compromised.

I think the Geddes approach requires loudspeakers and a setup with specific characteristics to work as intended - in my case this simply did not match.

After having briefly tested Dirac ART I would also assume that other, more traditional approaches (Geddes, Welti, DBA), even if executed with great care, will not lead to the same near perfect bass integration - even up to 150Hz (most other concepts stop at 80Hz max.)

 

[singular]

Bingo

Thanks this is actually very helpful. Seems like the geddes approach really might be compromised.

 

[singular]

Hello everyone, I'm deciding between an RME ADI-2 DAC (€~1k) and ADI-2/4 Pro (€~2.5k). The 2/4 would let me properly high-pass the mains (big floorstanders) and low-pass the subs, while the cheaper DAC would mean running the mains full-range and only low-passing the subs.

My goal is maximum SPL with the smoothest bass possible across multiple listening positions and potentially extend the LF extension to infrasonics. My mains also reach flat down to 25hz in my room with no EQ. (Though I do cut a huge low Q room mode at 50hz by i think -14db because of wall proximity)

It looks that what you already did is HP Shelf doing so by using Boost Cut (?) -14dB at 50Hz.
This means that you fitted your Polks r700 to your room fundamental - now the F6 is somewhere around 80-90Hz or so. ( compare with room fundamental )
So your speakers response is already highpassed to remove 12 gain of your room.

I do not want to talk more about 50Hz impedance peak damped this way too.

The thing is you hear now 25Hz which is one octave lower from that filter, but probably still in the Q of it.
It says that this subbas is for you, there, in time, however it could be product of 2HD.

To get better result in any case, you will need perfectly aligned each of ways in phase, and time.
Then you can do whatever you want, omnipolar, semi-cardioid, cardioidic, between mains and subwoofer, and subwoofers too.

Adding perfectly aligned subwoofers and highpassing mains at cutoff, you may endup with less THD for bass region.

That is probably not possible with unplugged ports due to their position and summing with both bass units.

But still below room's fundamental there is subbas folowing apartment longest fundamental (1st impedance peak / HP2).
And more down below is infrasonic wave created away from your listening spot and booming +12dB again (aligned in time).

By creating more subbass sources you get only more difficult time/phase pattern to solve, and with assymetry even more difficult.

My tip 1: Add DC blocker.
My tip 2: Measure FR and compare IR.
My tio 3: Equalize, plug, damp, align by IR.

 

[gnarly]

So maybe i should high pass at lower frequencies like 40hz to still make use of multiple LF sources in the above frequencies while keeping deep bass distortions to a minimum? That seems like the best of both worlds right?

I recommend getting a DSP that's easy to experiment with. It beats trying to think though how bass works (in rooms)

 

[girtab]

I think there's a misunderstanding here

It looks that what you already did is HP Shelf doing so by using Boost Cut (?) -14dB at 50Hz.
This means that you fitted your Polks r700 to your room fundamental - now the F6 is somewhere around 80-90Hz or so.

I don't use any high pass filters right now. I mentioned that I use a peaking filter without around ~1Q at 50hz to tone down the room fundamental by -14db. This means that bass extension at 25-30 is kept almost the same (maybe -1 or something), which definitely doesn't act as a high pass filter.

I do not want to talk more about 50Hz impedance peak damped this way too.

I don't see how this would be an issue if you mean damped in a perceptual sense?

The thing is you hear now 25Hz which is one octave lower from that filter, but probably still in the Q of it.
It says that this subbas is for you, there, in time, however it could be product of 2HD.

Yes it's within that Q, but is only affected by like -0.7dB or something and I do not percieve any HD when listening to a 25hz sine wave

To get better result in any case, you will need perfectly aligned each of ways in phase, and time.
Then you can do whatever you want, omnipolar, semi-cardioid, cardioidic, between mains and subwoofer, and subwoofers too.

Yes but I imagine the perceptual differences here are negligible if implemented as best as one can, it can never be perfect

Adding perfectly aligned subwoofers and highpassing mains at cutoff, you may endup with less THD for bass region.

That is probably not possible with unplugged ports due to their position and summing with both bass units.

I imagine an HPF would have a very similar effect to plugging the ports, especially when talking about THD since it reduces excursion directly, port noise is unaffected but was never an issue in the first place

By creating more subbass sources you get only more difficult time/phase pattern to solve, and with assymetry even more difficult.

The common consensus I get from people at this forum is that the more subwoofers you have, the smoother FR you can achieve, so perhaps it's worth the extra phase complications

Yes asymmetry will make it more challenging or may be the limiting factor but I'm trying to optimize for a normal living space and not a studio so imperfections are fine imo as long as you dont get phase cancellations

My tip 1: Add DC blocker.

I believe the RME already has that for its analog outputs

My tip 2: Measure FR and compare IR.
My tio 3: Equalize, plug, damp, align by IR.

I agree, it will be lots of trial and error

 

[girtab]

I recommend getting a DSP that's easy to experiment with. It beats trying to think though how bass works (in rooms)

You mean the licensed dirac stuff?

 

[singular]

Of course you can dig out infrasonic and ultrasonic from recordings.

I did both on my system succesfully.
Now I am happy it is removed.

Every sound starts with fast peaking impulse - ultrasonic crystal clear sharp sound tearing ears, sometimes low in level.

There is sometimes lot of infrasonic content you can recognize on well made system because ultrasonic peaks folow these sounds, and you need highs and a tad of ultrasonic to percept bass range (in phase).

In 90% it is not information you need or want for relax listening to music, just the opposite.

I do not know guys, if you have experience with shovel and mixing concrete in drum mixer.
To get the best mixture you need to look in the drum, and to listen carefuly every batch until is done...thick, greasy...

Doing so the whole day is the same like listening music on system capable of infrasonic and ultrasonic informations.
Then your brain is like connected to GHz line...tired after 1-2 hours completely.

You hear informations that are completely unimportant to your life, forcing the brain to catch and remember.

Nice experience, no more, thank You.

 

[girtab]

There is sometimes lot of infrasonic content you can recognize on well made system because ultrasonic peaks folow these sounds

This is technically true but the next thing you said

you need highs and a tad of ultrasonic to percept bass range

seems like a very odd take. Does anyone concur to this?

In 90% it is not information you need or want for relax listening to music, just the opposite.

obviously im not getting huge 12 inch subs to listen to relaxing music, i could do classical music just fine without subs, or even tiny bookshelves. But synthesized music very often contains intentional infrasonic content which does benefit from some rumble here and there and its made to be an experience as opposed to a casual low volume listen while you do some chores

 

[singular]

This is technically true but the next thing you said

seems like a very odd take. Does anyone concur to this?

obviously im not getting huge 12 inch subs to listen to relaxing music, i could do classical music just fine without subs, or even tiny bookshelves. But synthesized music very often contains intentional infrasonic content which does benefit from some rumble here and there and its made to be an experience as opposed to a casual low volume listen while you do some chores

I will go the simplest way step by step.
You already have the mains tuned to your room - could it be better? Might be with DSP and more type of fiters.

I doubt little because to me there is no useful music content below 25Hz.

Summing two 8" bass units you get more than one 12" area.
The thing that the units do not move in excursion a lot is good (if you hear content in level) because you have less distortion and Le variates less in motors.

I know speakers that big and I can say that those you have can play music from 5-6 meters at levels above 105dB - very loud in room, but allright for 83dB to your ears.

The new D-class stuff is always overestimated and often need DC blockers.

Try to add Allpass to frequencies where you want to equalize subbas, or higher bass.
It is merhod IIR, but it works...by not creating different shape or boost for FR, but just postpone the freq in time for brain to recognize.
The minus effect is that it is slowering the rhythm of music from lows up.

Adding two 12" subs to direct the bass to space is nice idea, however it works only in the room dimensions, reflect, reflect, reflect (reverb/die).
It can help a lot but room opened to apartment is method too.
Forcing bass to direct sound means to boost it in level for about 12-18dB imagine the power needed, and excursions to heat up air.

To me phase never cancel (except some short push-push), and is shifted always.
Moving bass...is not what you want - but stable bass stereo scene could be made by cardioidic pattern with well positioned subs to main source - that is in fact the direction where the sound is radiated by applying delay.
I am not sure if Dirac or others can compete with what you want in this case.

Also I am not sure how is made crossover, bass speakers, and ring radiator in your speakers to experiment with ultrasonic content...anyway it means superslow filter in DAC what end up in some sort of IMD on mids.
Digitalized music is designed for brickwall filters.

 

[gnarly]

You mean the licensed dirac stuff?

Nope. A DSP with crossover and filter functions, like something from mini-dsp. Or better, a loudspeaker management processor from the prosound world, like CoLinear or similar. ( best option ime....used prosound gear works)

Just needs to be able to handle the line-level I/O options you want to experiment with.