What are the downsides of DSP?

[fpitas]

this was like the go-to "EQ doesn't fix things" answer back when I started EQing.
it is not wrong, BUT without EQing every point in the room is even wronger lol.
I mean, you optimize to one area, most other points will still be better than before, especially in the bass

I EQ, so no argument here.

 

[kemmler3D]

If DSP doesn't have any real downsides, what is the reason the majority in this poll only uses it to the Schroder frequency?

Should we correct to Schroder, or full range?

I would like to gather opinions from ASR members as to whether we should apply room correction to the Schroder frequency, or whether we should do full range correction from 20Hz - 20kHz. There appear to be two schools of thought: - Correction to Schroder: aims to only correct bass peaks and...

www.audiosciencereview.com

Problems with room response are 3D and no two points in the room, above Schroder frequency, will have the same problems. EQ is 1-D, it changes all of the sound in the same way. So, if you do that, it only works for the single point in space where you measured the room response.

Everywhere else, the results are likely to be worse, or with some random improvement.

This isn't a downside of DSP in general so much as a limitation of EQ, which is just one type of DSP.

DSP that tries to go beyond this is starting to hit the market, for example Dirac ART uses multiple speakers, multiple EQs, and multiple delays to correct more than just one point in space. It's more than a 1-D solution, I think you could at least call it 2D or even 3D if you include time.

 

[Trdat]

There are two big downsides of DSP:

1. the learning curve
2. easy to get bad results if you don't know what you are doing.

DSP software varies with the amount of automation (and therefore ease of use) and features that it gives you. I have most experience with Acourate (which I use myself) and Audiolense (which my friends use). It takes me several hours to do in Acourate what Audiolense does in 15 minutes, because of the amount of automation in Audiolense. Acourate has some automation, but not much. It otherwise forces you to go through steps and make decisions. I can tell you this was a MASSIVE learning curve for me. Although I am now reasonably proficient at it, there are still things that Acourate can do that I have not explored.

But even taking in consideration the automation of Audiolense it still took me up to 4 years to learn and understand the graphs, what the ideal measurements should look like and how to tweak the features to achieve the correct objectives. Unfortunately, there is no manual that teaches these things it takes time, effort, forums and helpful people to get to the bottom of it. In saying that the end result at least for me is state of the art sound system but I suppose one can just purchase the same quality these days.

Ultimately, I would totally and whole heartedly agree with Keith major learning curve and initially till you have overcome the learning curve you will get bad results.

 

[dasdoing]

the learning curve is as bad as it gets. Though the "standard" REW procedure (automatic EQ on VAR curve) is pretty straightforward and will give good (as in improvement) results.

 

[Barrelhouse Solly]

OK, in the sense of listening, I'm a subjectivist. I like to think that my preferred sound is one that reproduces live sound accurately. I think I probably have subjective preferences that aren't perfectly flat frequency response. I first experienced room correction with an AVR with Audyssey. I liked the results although I increased the subwoofer volume a bit. Also, I listen mostly at relatively low volume so Fletcher Munson is always in play.

I've played music and sung for most of my life and one thing I know for sure is that live, unamplified music almost never sounds the same in different places.

 

[Enstip]

DSP needs to be performed at higher resolution than the samples and then properly converted back to sample size. If this is done and there is no overflow/clipping, there is no down side to it other than expense and some additional complexity.

Hi Amir (loving your work, by the way. Thank you). Did I read somewhere that you use the RME ADI-2 DAC FS like me? Do you know if it meets this criteria in its DSP?

 

[Enstip]

Thank you all for your replies. I’ve not been ignoring them - I have been reading all of the referred to content and then referrals within those. As you say, this subject is massive. The one thing is clear is that I need to experiment more, off the back of better knowledge in the first place.

 

[MaxwellsEq]

But, I wondered if it’s all upside. You don’t get something for nothing, right?

Frequency is a transform of time. So if you adjust something in the frequency domain, you make changes in the time domain. That is the "not getting something for nothing" consequence. At this point, however, there are quite a wide range of opinions on whether this produces audible artefacts.

 

[holdingpants01]

Can you post your before and after (measured, not predicted) results? One reason could be the EQ takes care of the peaks but does nothing the the nulls, so the sound seem more flat but in reality isn't flat at all, just lacks energy in the low end where the peaks were

 

[mhardy6647]

The latency bugs me the most. YMMV, though

 

[Purité Audio]

If you correct only in the minimal phase region of the FR there is a complete inversion no delay.
Keith

 

[dasdoing]

beware the input lag https://www.rtings.com/tv/tests/inputs/input-lag
a FIR delay can actually end up syncing the system lol.

 

[Enstip]

So, a few things done.

Read and researched after your replies.
Watched and hopefully learnt from videos by Amir and Floyd Toole.
Switched from REW to the HouseCurve App by @Greg Wilding (which, as an iPad user and for my simple needs, is more convenient to use than REW).
Made use of the new remote interface for the RME DAC which makes the experimentation process so easy.

….and I’m getting better outcomes.

Thanks for the feedback and direction.


PS just for interest, here is a screenshot from my iPad showing the new RME remote for my ADI-2 DAC alongside my music app. Functionality I could only have dreamed of previously and rolled out for free by RME. Superb.