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Sub Integration

Reading is good , but a cheap unit from MiniDSP or a more expensive antimode is what you need to integrate a sub properly (low bass configurable eq etc)
First thing to do is measure , so get a Umik-1 mic (from minidsp) for $70 and get REW (free) and see where the problems are.... take it from there
 
Thanks for replies both. Will do some reading and looking at dsp at weekend.

I'm in for an MDAC2 which will have DSP inbuilt, but thats a while away yet & I haven't quite got my head around it yet.

The thing that sticks out for me so far is that MDAC2 DSP effectively = PC Software DSP i.e. the inputs to the mains and the sub are both equalised as the dsp is at or close to the source.

Whereas a separate dsp box would presumably apply dsp to the sub leaving the mains alone.

Maybe it'll be clearer once i get some time at the weekend.
 
There is initial sub integration and then "tuning"
Initially you have to get the sub to take over from your speakers and do so smoothly at the same level etc, there you will use sub crossover, level and polarity (phase)

You CAN add extra DSP to the integration stage and bypass the subs controls with a DSP unit in front of the sub , this will give you a lot more tools to play with...

Once you have got that right , then its time to use low bass eq etc to deal with room nodes and bumps in the LF performance.
This is the "tuning" stage.
DSP here should really look at the whole system and correct that...

Be aware of one thing , DSP CANNOT be used to treat dips in the low bass response , it must not be used to boost , as often what you are trying to boost is a room null that will consume infinite power.
 
rtrt said:
Thanks for replies both. Will do some reading and looking at dsp at weekend.

I'm in for an MDAC2 which will have DSP inbuilt, but thats a while away yet & I haven't quite got my head around it yet.
Click to expand...

For this you will need a UMik1.. Buy one and play with the free software REW which is available elsewhere.. the learning curve with this software isnt too bad (the help files/forum are very good) AND its stuff you will need to know/understand to apply the same to the MDac2.

So NOW is as good a time as any to get a USB mic!! Plenty of time to play and learn. :)
 
Yes it can. It wont be perfect, but this hobby is all about finding the compromise that works well enough to your ears.

My room is pretty much flat (+/-3db from 30hz upwards) with one spike at 55hz.. Simple fix with parametric EQ in Jriver. Thats a pair of Ergo IX speakers and a monolith DF roughly halfway between them.

Having a mic lets you experiment with what different positioning makes for both speakers and sub(s), settings changes on the sub etc etc... All good fun!


Felty99 said:
It seems as though the minidsp website is down. Anyone else having the same problems?
Click to expand...

Its working fine for me.

Direct link to the Mic:

http://www.minidsp.com/products/acoustic-measurement/umik-1

Thanks,
Sam
 
sam_cat said:
Yes it can. It wont be perfect, but this hobby is all about finding the compromise that works well enough to your ears.
Click to expand...

+1


IME having a very quick, precise sub that is at ease pressurizing the listening room makes the integration much easier.
 
Rodney gold said:
Be aware of one thing , DSP CANNOT be used to treat dips in the low bass response , it must not be used to boost , as often what you are trying to boost is a room null that will consume infinite power.
Click to expand...

Now there is a guy who speaketh golden words.
Any room correction system can ONLY compensate for bass boost nodes, NOT bass cut. I have the very same issue in my room and NO amount of playing and fiddling will restore the bass hole I experience. Simple physics can prove this, if from where you are sat there is a 'hole' on the bass it is almost always due to a cancellation effect, if you try to correct this you will be driving your sub into hell to fill something which can't be filled.

If anyone thinks it is not true and they can overcome the bass cut in my room without moving the speakers, making the sub bounce about like a football from where I sit I will pay for the return trip to my house, all meals in the most expensive restaurant here in Luxembourg, all the drink you can consume and 500 Euro pocket money.
 
sam_cat said:
Yes it can. It wont be perfect, but this hobby is all about finding the compromise that works well enough to your ears.
Click to expand...

That's why it's a golden rule: as you say, one sub is never perfect. As you say, it's a compromise. It doesn't have to be.

To unpack that a bit, to see why it's true, consider that real in-room bass is nowhere near as 'non-directional' as it's sometimes suggested. It's always possible to locate one LF source in a 'lopsided' presentation.

That's partly because LF emanating from a single point source instantly generates stubbornly fixed standing waves, triggers nodes and creates peaks and troughs that permeate your room like a photograph of ripples in a pond.

In fact, that's not a bad metaphor . . . drop a single stone into water and a regular pattern of rings form. Drop two stones and the ripples interact chaotically, partially canceling. Situating two LF generators in and out of nodes - even without DSP and EQ - just by a bit of trial and error - instantly improves the evenness of LF response. It's the right way to do it. It's why all high end cinema systems are .2. It's why active speakers generate such clean, natural LF. It's related to the excellence of bass from open baffles.

Trying to get good LF from a single sub is a fool's errand relative to doing it right in the first place - which just works. EQ and DSP are like putting plasters on a broken leg. Why not fix the leg?
 
Lots of food for thought for the weekend above - thanks!

Have a question re the MinDSP in the meantime

http://www.minidsp.com/products/minidsp-in-a-box/minidsp-2x4

The spec of the unbalanced unit offers 0.9V/2.0V input options, but only a 0.9V output option.

2.0V doesn't 'feel' like sufficient headroom or at least a bit close for comfort.

0.9V out feels way too low for a digital source. Are subs designed with an assumption of a lower than 2V input?

One of the reviews on the page linked shows an unhappy customer, but with 3 reviews in total, its not clear if he's an exception or if its a common problem.
 
ItemAudio said:
That's why it's a golden rule: as you say, one sub is never perfect. As you say, it's a compromise. It doesn't have to be.

To unpack that a bit, to see why it's true, consider that real in-room bass is nowhere near as 'non-directional' as it's sometimes suggested. It's always possible to locate one LF source in a 'lopsided' presentation.

That's partly because LF emanating from a single point source instantly generates stubbornly fixed standing waves, triggers nodes and creates peaks and troughs that permeate your room like a photograph of ripples in a pond.

In fact, that's not a bad metaphor . . . drop a single stone into water and a regular pattern of rings form. Drop two stones and the ripples interact chaotically, partially canceling. Situating two LF generators in and out of nodes - even without DSP and EQ - just by a bit of trial and error - instantly improves the evenness of LF response. It's the right way to do it. It's why all high end cinema systems are .2. It's why active speakers generate such clean, natural LF. It's related to the excellence of bass from open baffles.

Trying to get good LF from a single sub is a fool's errand relative to doing it right in the first place - which just works. EQ and DSP are like putting plasters on a broken leg. Why not fix the leg?
Click to expand...

I disagree.

In a listening room I would say it is not possible to locate where LF (under 80 Hz) frequencies emanate from. In a stereo setup the crossover will seldom be set over 50 Hz so one should be perfectly fine with just one sub.

In practice I think that in most cases it is clearly easier to integrate just one sub in a stereo setup.

And more importantly AFAIK one really good sub works much better than two average subs.
 
Rodney gold said:
Output Voltage will be more than enough to drive any active sub.
http://www.minidsp.com/applications/dsp-basics/gain-structure-101

1 sub is perfectly fine , 2 subs is NOT the magic bullet to cure all room bass ills..
Click to expand...

I agree there is no magic bullet - if there was, it would be treating the room itself - but starting off on the wrong foot (ie, one-legged) is a hiding to nothing. There's a reason all the best systems have stereo bass. It works.

Of course you can get 'quite good' LF from a single sub. And if you're happy to stop there, great. On the other hand, if you want to do right, at least try dual subs. You might not so readily settle for lopsided thereafter . . .
 
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