Room Correction

I think the apprehension about digital room correction is misguided. Analogue is by no means superior (that is an audiophile myth).
Room acoustics should be divided into two areas: above and below the so called Schroeder frequency, in your case probably about 130 Hz. Above that, all you can realisticaly do is apply a bit of damping with rugs, bookcases etc. Below the Schroeder frequency the resonance peaks (and dips) are so far apart and so large that they can be distinguished quite easily, and greatly disturb the sound, with boomy bass and slow decay (hence the term slow, which in reality refers to the room rather than the speakers). If you look at the in-room frequency response of speakers the deviations from a flat response are truly horrendous (easily +/- 10 dB, compared to +/- 0.2 dB for good electronics), and completely mask any imperfections earlier in the chain. So something has to be done.
Full range main speakers have the disadvantage that they have to be located for best midrange response and that is not necessarily best for bass. So many people prefer separate subwoofers that are designed for deep bass, and can be located for best bass response. However, just one sub will still give huge peaks and dips. Hence the method to smoothen this with multiple smaller subs. See here for a clear introduction and further links: http://www.acousticfrontiers.com/20101029using-multiple-subwoofers-to-improve-bass-the-welti-devanti...
On top of this, equalization is still very useful, and more succesful with multiple subs than with one, because the peaks are lower, and because the equalization will work over a larger listening area. With one sub, the response will only be correct in one listening position.
There are various ways to equalize the response. The easiest is to use a DSpeaker Antimode 8033 for the subwoofers. It is an automatic system that analyses the in-room response of your subs, and then designs and applies a correction curve. see here: http://www.theabsolutesound.com/articles/dspeaker-anti-mode-8033-dsp-subwoofer-equalizer-tas-204/ I use one with great success.
The alternative is to do all the hard work youself, with the REW software and a calibrated microphone. Correction can then be achieved with a miniDSP unit. This is a bit cheaper, but I would not bother (REW is quite hard to use).
DSpeaker is about to introduce a complete preamplifier/DAC/room eq system, the X4, but that is expensive and may not be necessary.
Finally, and perhaps not of much use to you, but dipole speakers like my Quad electrostats suffer far less from room modes, and hence have an exceptionally clean sound. However, they are huge, and need space (at least 2-3 feet for the smaller 2815 model, and more for the bigger 2915) behind them (but not on the side). If you can find room for them, they are gloriously absent: you hear music rather than speakers. They also have dynamic limitations, but should be fine in a room like yours.

When life and living in your room gets in the way of fanatical setup for your speakers, err on the side of life and living. : )

Well, setting up your speakers properly is certainly a lot less hassle than forever worrying about cables. It also makes a far bigger difference. As the guide Michelin would say: vaut le voyage.

Consider using omni speakers. Considering that you do not place emphasis on listening from a fixed location they might be perfect for you.

Analogue is by no means superior (that is an audiophile myth).

This statement is not correct at all all. Some people may not be able to hear it, but room correction systems will convert that analog to digital before doing DSP and corrections. Then convert back to analog. The end result may not be bad sounding, but you are definitely changing the sonic signature and you will lose the original character of the sound. At this point you are entirely dependent on the ADC and DAC circuits in the room correction device.

generally, a room correction system is used when you cannot properly treat the room acoustics by using panels or bass traps. Or if you have a digital source, such as a HT processor.

It is a myth. Just read up on the Nyquist Shannon theorem. If you can refute this, you are in line for a Nobel prize.

Room correction is fine, but it is no substitute for good room acoustics, and speakers which match your listening style.

First, talk to GIK Acoustics. They have great products and advice, they can help you out. Putting up absorbent curtains, even if left open will help a great deal. Lots to do on the ceiling and in soffits as well.

I use a hybrid room correction approach. A subwoofer with DSP, but the main speakers I leave alone.

Unfortunately, with limited space, you want a speaker with narrow, not wide dispersion to give you the best clarity at your seating location.  Also consider putting plush furniture BETWEEN the speakers, instead of your audio rack.

Other alternatives are to simply start with small speakers. They will be less prone to bass problems. Maybe talk to Fitz. He can design speakers for you specifically for close wall placement, and can pick out some good tweeters which will have controlled coverage.

Other alternatives are small horn speakers, such as the Hsu satellites. They also will do unusually well in tight situations.

Above all, AVOID speakers with very wide dispersion.

Best,


E

I should also say, if you are interested in DIY solutions, the LM-1 is ideal because it is specifically designed for near-wall and bookshelf placement.

https://speakermakersjourney.blogspot.com/2016/02/the-lm-1-bookshelf-version.html

It has relatively narrow dispersion, and unusually high sensitivity due to it's design considerations.

Best,


E

I agree that good acoustics are important. However, below the Schroeder frequency this is basically a matter of the size/dimensions of the room. The bigger the room the lower the Schroeder frequency, and the more the inevitable room modes can be kept away from the main listening frequencies. Unlike above the Schroeder frequency, at these low frequencies normal damping material will not help - you need large and ugly bass traps.

Above all avoid speakers with very narrow dispersion - they have very small sweet spot and never sound natural except in an open space.

I find the GIK Soffit Traps and lesser bass panels quite attractive, and better performing.

Also, as written by experts in room acoustics, bass traps allow EQ work. The combination is unbeatable.

Above this however, tight bright rooms need help too.

Best,

E

Nyquist Shannon theorem

Yeah, I read about that years ago.  It doesn’t hold water as I can clearly hear differences between 44.1 sampling and 96khz sampling.  You are also not realizing that not every DAC is created equal.  The conversion from DAC square stepped output to true analog waveform is where DAC circuits have huge differences.  If you believe in those theorems and statements about pure measurements, the fine.  There are many others here that can hear minute differences that are not documented by these measurements you like to post.

It is a myth. Just read up on the Nyquist Shannon theorem. If you can refute this, you are in line for a Nobel prize.

these kinds of statements are not made by real people, explorers, or the people who came up with the nickel theories that are being thrown around the room like so many manhole covers.

When we see this, we are usually dealing with mid level dark age engineering clerics who want their books of dogma to be simple and straight.

Note: the books were never meant to be dogma, they were meant to be theoretical guides for you to start your explorations in finding the new. OK??

Nyquist, if he was still around, might be the first to shout you down and ask you to stop sullying his name with this insanity.

We don’t know everything and we don’t take these theories and paste them over the unknowns and call it solved.

the very ’ raison d’être ’ of the ear is to do the world’s most complex fft analysis that is known to be performed across a wide swath of intermixed harmonic transients and then process them with the most complex device known to humanity: the human brain.

And, it’s not about the gross signals, it is about the super fine micro differences in hundreds of intermixed harmonics, across time, analyzed as a set, over a long, long time.

No hardware or computer can complete this task.

Do you know why we use sniffer dogs at airports?
Because they are better than all the machinery that has existed up to this date.

Do you know why we trust human hearing in complex music signal analysis?
Because it is better than any machinery that has existed up to this date.

Anyway, I’ll stop wasting my breath on this -and turn to fresh air and sunlight, etc. I seriously doubt any text typed on the internet is going to ever convince anyone who find this stuff outside their reach. By definition, it can’t reach them...


Think about it. The worst fear in the mind of someone like Einstein, would be that his theories would hang around too long, as that means people have become dogmatic and stupid, and can't move past where he made it to.

I’m not finding REW hard to use at all. I’m finding it difficult, though, to decide on how to correct my issues..

@willemj - man, I’m asking this out of curiosity, I’m not being purposefully confrontational, but are you possibly on the autism spectrum? Not that it matters to your worth as a human at all, and I'm not poking fun. I just get annoyed with some of your posts because you are so absolute in your belief that everything you think to be true is so and are very condescending to those who don’t automatically accept those truths or manifest them how you think they should be manifest. This adherence to one particular mode of understanding and your lack of tact made me curious. If that is indeed the case, I’d certainly be getting less riled up by your posts.

A person who uses subs for bass can feel free to use digital room correction (like the DSPeaker Anti-Mode) without paying a penalty to higher frequencies. Send only the sub signal through the DSP, and the main signal straight to the speakers' amp.

@bdp24    

+1 Very good point. That would be my preferred way to do it.

That is how I do it is as well. Not because I believe the digitization degrades the sound, but because room equalization above the Schroeder frequency (in my room about 90 Hz) is not feasible. Of course, just equalizing the subs leaves the bottom end of the main speakers below the Schroeder frequency unequalized. This is where a large room is beneficial, and/or some equalization of the main speakers´ bottom end. But equalizing, say, 150 Hz produces a very localized benefit that may not be worth the trouble. Fortunately my Quad stats are dipoles and hence do excite far fewer room modes.

Now Willem, take that dipole room mode behavior and extend it into the bass region, with an OB/dipole sub. NOW yer talkin'! The GR Research/Rythmik OB sub provides dipole benefits where they matter most, at low frequencies.

Absolutely. I looked into dipole subs, but there was nothing on the market here in Europe. Also, the designs that I saw were huge: how could I reasonably persuade my loving wife who already puts up with the Quad electrostats?

Thanks, that is interesting, and Kenny’s subs do indeed look good. However, they are still too large in my situation. My B&W PV1d sits discreetly tucked right into the corner behind the Quads, and thus virtually invisible. That position (advised by the DSpeaker engineers) also gives some nice corner reinforcement that is then equalized by the Antimode. After recently reading a lot more about subs, next on the shopping list is now a second PV1d for the corner behind the other Quad, for more power and a smoother response.