User:Mikec
From DRC
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Introduction
Its taken CD over 20 years to reach reasonable acceptance for high end audiophiles. Now we are at a junction of High Definiton future, Engineers are finally starting to understand how to make digital components that do what CD promised, Input=Output. The Irony is it comes at a time when we dont even need to have the CD at all. Jewell cases are no longer cool. Download is where its at. The term Rip and replace takes on a whole new connotation.
The latest digital amps (including class D semi digital) now no longer need to make any excuses, delivering high power, cool running and low distortion that class A and Class B amps only dream about. With true digital amps such as the Lyngdorf Millenium, we can dispense with the last vestages of mechanical playback, a spinning platter in our CD players (allright so a hard drive is a spinning platter also.
With the Music ripped losslessly to a storage device on the other end of a wireless network we even gain whole lot of space occupied by those jewell cases, and more to the point enjoy music that we had long forgotten we purchased.
Having dreamed about an end to end digital media chain I have finally taken the plunge to see this out. This Wiki has provided great inspiration, and addressing the room has now risen to the top of the ToDo List.
You might like to visit my website to find out more about me
Bring on the Room Correction
This bit will be under permanent construction. You might call it a WikiBlog. This section contains notes for my own sanity, but might also be of interest to other DRCers.
So why bother with Room Correction and Equalisation? Well lets come back to that in a few moments. what we need is some context and background.
25 years ago while still at high school, my brother and I used to run a mobile disco. We always took a lot of pride in the way our rig sounded. However Money was tight.Necessity is the mother of invention, so we built our own mega bass Bin Speakers as well as amps.
I dont know whether it was the time or age, but no matter where we were or what we played, we always enjoyed the sound. I have memories filled with tight bass guitars, soaring vocals and the wack of the Snare drum, so fast that it took you to another place. Ah Disco nights, oh the chicks were pretty cool too.
The amazing thing is those 70's tracks, Disco or Ballads are still being played, from Bohannon to Labelle and Soul favs like Marvin Gaye, Chi Lites and Luthor Vandross.
I've been pretty happy with my system upto this point. Primare A30.1 Amp Driving Dynaudio Contour 3.0. Mr Kessler described the Dynaudio's like High Quality 70's Dynamic loudspeakers on Steroids.Wow how appropriate.
The system was smooth and detailed at the same time. Have you noticed that positive are always described as a balance of two attributes in Hifi? In Any case it was very enjoyable whether you sat down for detailed listening or just wound it up while you were doing other things in the house.
However after going over a year without upgrading the system, memories of that golden sound of those disco nights are coming back. I know that the sound I can hear in my mind is probably more down to imagination than was reality at the time, but its there never the less. So the itch needs to be scratched, here we go.
So why bother with room equalisation?
There were always a few things that bothered me about Hifi.
1. The amount of improvement in Amps, CD's etc seem to be refer to sub 0.01 percentage points. Frequecy response were flat, jitter was down at the nano seconds. Yet there staring in our face were loudspeakers that at best had a frequency response that makes the sleeping policemen down the roads near where I live look like the great wall of China. Put the speaker in a room and we now had the great wall of china goingup and down the Himalays for frequency response. Why do all the HiFi mags tell us to go to a good dealer and listen to a bit of kit before we buy? when by the time we get it home, it does'nt sound anything like the demo room. Most demo rooms I have visited have been pretty underwhelming in any case.
2. Ever since Tone Controls were tagged as cancerous and born of the Devils children, we have been spending more on our cables and interconnects than the kit! Yet I will admit that I have heard the difference that a cable can make to the sound. The sad fact is that CD's can have different tone, and can sound good on one system or another. With sophisticated DSP technology we can now tune our system to the CD.
3. CD's themselves can sound good bad or indifferent, and often we use the music as tone controls. ie we play the stuff that sounds good on our systems and leave the stuff that that sounds rubbish on the rack. Have you noticed that when you change a major component your fav tracks can change also?
4. We get acclimatised to our sound systems. Changing a component needs careful assessment over a Month for us to decide whether we like it or not, and then you need to the old one back for a month to make sure that you did not acclimatise to the new one..... What we need is something that makes a major change in what we hear.
So will Room correction be the big jump... read on.
Timeline
Pre April 2006
System consists of laptop running iTunes. This accesses a Network Attached Storage NAS box the Buffalo Linkstation which runs a miniture Linux kernel and the Samba file system. 5 laptops in the house connect to this through an 802.3 Pre-N wireless hub from Belkin.
The laptop streams apple Lossless files to an Apple Airport Express, which is connected to a Behringer DEQ 2496 Ultra Curve Pro via Optical SPDIF cable acting as both DAC and digital room correction unit. I make use of the Behringer to reduce a severe boom at around the 100Hz mark in my listing room. This then drives my main amplifier a Primare A30.1 integrated through balance connections. This in turn drives a pair of Dynaudio Contour 3.0s via QED Genesis Cables.
The Ultra Curve includes a basic Spectrum Analyser and white noise generator for doing coarse grained analysis of room frequency response. You do need the Behringer measuring microphone though. Oh and a long balanced microphone cable as well as a tripod /clamp to hold the microphone in position.
April 2006
Just bought a Lyngdorf TDA2200 full digital amp to replace my Primare. Will listen to this for a few weeks and compare this with and without the Behringer. The TDA2200 includes its own Room Correction module with much easier control of parametric filters via a laptop. Will start to collect the bits I need to set up a higher resolution measurement and correction solution.
Here are the things I want to find out
1. Does using the Behringer purely as a digital passthrough to convert optical to balanced AES improve the sound, vs feeding optical directly into the Lyngdorf.
2. How far can I take the room correction with the standard DSP of the TDA2200
3. Do I need to go to the new Lyngdorf Room Perfect solution coming out in May?
4. Should I go fully active and replace the Dynaudios with Tacts MH1 speakers (will need additional amp). The TDA also has the ability to be a digital active cross over.
Initial reaction of the TDA is improvements in all areas. Significantly more texture to just about every voice and instrument. The sound is not edgy at all, but sometimes there is so much detail that your brain cant cope, kind of like driving a fast car around a race track. there is that fear factor until your brain gets with it, then the grinning starts. Texture and detail also manifests itself in amazing separation of individual elements of the music, most noticeable with simple acoustic music such as Nora Jones.
Strangely the Room Mode that I had at about 100hz does not seem so pronounced. I can still hear it, but the amp is clearly controlling it so tighty that you actually dont mind it so much.
After a few hours of casual listing (while I'm surfing on the laptop) it starts to dawn on me that I can almost hear the difference between the sound of the amp vs the sound of the room. Imagine an object on the beach partly covered with sand, you can clearly distinguish the object vs the sand. It really wants to make me want to remove that sand and give the object a real polish and hold it upto the light and enjoy it's form in the sunlight.
Need to be careful however. I HAVE removed the Behringer as well as its DAC section and cables. On the other hand I could'nt do this with a non Digital amp.
I'm also aware that my general awareness of changes or improvements sinks in over several weeks, so I tend to reserve critical listening when I have had the component for a few weeks. Lets see how this develops.
Room Measurement
For those that are interested in using the Cara 3D room optimisation software here is what its estimation of the room response looks like.
Just bought a Behringer UB802 mic preamp ready to do some advanced measurement £39.0 from a music shop on the Totenham ct road. I needed this as my Beringer ECM8000 measurement microphone needed phantom power.
Downloaded the room equalisation wizard onto my SUSE Linux 10.0 Laptop from http://www.hometheatershack.com/roomeq/
Had to upgrade my Java Runtime to 5.0 works straight out of YasT with repos set up correctly. Runs nicely. The Wizard has found theIntel Sound card on the laptop (Lenovo z60m).
Hmm need some more bits looks like I need a SPL meter. Just ordered a radio shack SPL meter off eBay £39. After half a day of setting up the wiring cables and a playing around with soundcards Here is the first set of measurements, and filters to correct that nasty bass boom.
You can see from the graph, that I have a bass peak at 45 and 68 Hz. Before the TDA the boom I was experiencing was closer towards 100Hz, but the behringer was just not high resolution enough to see the problem in detail and as two peaks rather than one.
The Wizard then allows you to set the target level (Seen here at 72db). Good Idea to only correct the bass to start with. By pressing "find peaks" it will then locate significant peaks above the target level. Then press assign filters and it will generate the filter parameters for you. You can see it it has defined two parametric filters, with centre frequency, Gain and Q. Way Cool. The graph also shows you the predicted corrected response.
I then programmed these into the TDA's Filters, took about 30 secs, and assigned it to preset 1. We have our first correction done.
Hmm see that nasty dip at 113Hz, The wizard will not automatically correct dips. You need to do this manually. I always felt that Bass Guitar did not quite have the energy or extension. I manually added in a 6DB increase at 113Hz with a very sharp filter. This seems to have just added enough boost back for me to notice an improvement. Nice!
May 2006
Having set up to TDA with basic parametric equalisation to deal with a room mode at approx 50Hz, I have now had a chance to listen to the system for a week or so.
The first thing that has been interesting is that the TDA seems to be reasonably innert to digital cables and source components. Whether feeding it via the Airport express, Behringer or from my Toshiba SD900 DVD player, the quality of the sound is very consistent.
The second is that it has become even more obvious which recordings are good or just average. Its like seeing your favourite actress with no makeup on. Its more natural, but you may not like what you see!
