Equalizer update

[jhenderson010759]

gerG -

I found a Roland M1000, 24-bit digital mixer for $299 on the web and ordered one for experimentation. This unit can perform the digital attenuator function, operates with 24-bit resolution and allows sourcing my CD player and/or my PC via USB to the Behringer DEQ and DCX. I don't think resolution loss will be an issue. Here's why:

If I upsample from 16 to 24-bits before sending to the Roland, I should be free to effect an 8-bit attenuation, approximately 45 dB, with zero theoretical resolution loss. This is because upsampling produces samples with valid information in bits 23..8 and either dither or zeros in the least-significant byte. So, when the Roland attenuates the input signal using 24-bit arithmetic, the least-significant eight bits of each sample may be truncated without a loss in resolution.

As my entire CD collection is stored on my PC in .ape format, I can use Foobar to upsample to 24-bits during playback - just as I do in my headphone setup. If I can find a a CD transport that up-samples, I should be in good shape.

What do you think?

[gerG]

That sounds like a great approach. It was also quite informative. Is this a common approach for upsampling? I had always assumed that they interpolated to get to higher resolution, but this is certainly easier. I should think that a 45 db envelope would be plenty. Plus you get to have yet another digital toy in the loop!

As an alternative, you could also do the digital volume control on the PC after upsampling.


gerG

[Az B]

Originally Posted by jhenderson010759

What data format do you use for the digital connection between the DEQ and DCX? I need to use SP/DIF from my CD transport to the DEQ, but it isn't clear from the DEQ manual whether it will simultaneously drive the AES/EBU outputs when receiving SP/DIF inputs via TOSLink. Is that your configuration also?

AES/EBU and S/PDIF are very similar. AES/EBU allows for manipulation, but it can be set up the same as S/PDIF and they're pretty compatible.

Here's an adaptor:

http://www.innovativemusic.com.au/Pr...htm?sync.htm&2

Az

[jhenderson010759]

Originally Posted by gerG

That sounds like a great approach. It was also quite informative. Is this a common approach for upsampling? I had always assumed that they interpolated to get to higher resolution, but this is certainly easier. I should think that a 45 db envelope would be plenty. Plus you get to have yet another digital toy in the loop!

As an alternative, you could also do the digital volume control on the PC after upsampling.


gerG

Even if another technique were used to extend the redbook 16-bit data to 24-bits, that data would not represent genuine, additional resolution. So, how could one argue that truncating it as part of an attenuation would represent an actual data loss?

I want an attenuator with a physical knob in my playback loop. Haven't you ever fired up your media player in Windows, only to discover that someone had previously ratcheted the Windows volume control to maximum, then left it there?

[gerG]

Ouch, touche. I am exactly the same way about having a volume control knob, preferably within arm's reach of my listening chair. I hooked up a system once that went from source to x-over to amps, and although it sounded great (dynamic as all he11) I could not deal with the lack of control. Just another character flaw that I have to live with, I guess.

gerG

[jhenderson010759]

Originally Posted by jhenderson010759

gerG -

I found a Roland M1000, 24-bit digital mixer for $299 on the web and ordered one for experimentation. This unit can perform the digital attenuator function, operates with 24-bit resolution and allows sourcing my CD player and/or my PC via USB to the Behringer DEQ and DCX. I don't think resolution loss will be an issue. Here's why:

If I upsample from 16 to 24-bits before sending to the Roland, I should be free to effect an 8-bit attenuation, approximately 45 dB, with zero theoretical resolution loss. This is because upsampling produces samples with valid information in bits 23..8 and either dither or zeros in the least-significant byte. So, when the Roland attenuates the input signal using 24-bit arithmetic, the least-significant eight bits of each sample may be truncated without a loss in resolution.

As my entire CD collection is stored on my PC in .ape format, I can use Foobar to upsample to 24-bits during playback - just as I do in my headphone setup. If I can find a a CD transport that up-samples, I should be in good shape.

What do you think?

Upon reflection I don't think a 16-bit digital source of any kind (including my CD player) should be a problem after all. It is a virtual certainty that 16-bit sources will be arithmetically shifted to 24-bit significance (per above) upon receipt by the Roland. This is required in order to normalize the full-scale ranges (volumes) of all input sources. Bam!

[gradofan]

It's been 1 1/2 years since this thread's been added to. Where are you all now? Have you found new EQ settings, tried different programs, come up with other ways to measure headphone accuracy? Since I last posted, I'm DEQ-less (well, almost), and only have the EQ on my mp3 player. What has changed for you guys (and girls?)?

[gerG]

Jeez, my luck that I browse head-fi right after you dug this thread out of the dumpster.

I started looking into what was wrong with my technique. One big problem was that I was using a free-field mic for headphone measurements. Another issue was separating cavity effects from the headphone native response. I devised a mic method that gave me the data to separate the effects. I had to shelve the effort in January due to the real world intruding into my little diy lab. Some day I will lock myself in there again and finish up what I started. In the mean time I just enjoy the music and stick with small projects.


gerG

[jhenderson010759]

Originally Posted by gradofan

It's been 1 1/2 years since this thread's been added to. Where are you all now? Have you found new EQ settings, tried different programs, come up with other ways to measure headphone accuracy? Since I last posted, I'm DEQ-less (well, almost), and only have the EQ on my mp3 player. What has changed for you guys (and girls?)?

Aside from the poor reliability of the gear, I like the Behringer more and more. I have three DEQ2496s on my surround rig to equalize fronts, center and rears. I use the DEQ and DCX in my den for the K1000s+Sub and actively driving the N.C. Rhythms. And, I use a DCX in the garage for speaker building. Very flexible, good-sounding, well-measuring gear.

[Bullseye]

After three years since the last post, how is the DEQ working for you guys?

I am reviving this thread because I am going to buy either this week or next week the DEQ2496.

As a source I will be using either PC with UCA202 external sound card via toslink cable to DEQ or a Cowon D2 mini jack with a mini-XLR male converter.

I am thrilled now after reading this thread about the use of the Ultracurve Pro with headphones. I have read a lot of this product before, but mostly with the use of speakers.

[ironmine]

Originally Posted by Bullseye

As a source I will be using either PC

Bullseye, if you intend to use a PC as a sorce, why do you need DEQ? You can do all equalization using Foobar's VST-plugins.

[Bullseye]

Originally Posted by ironmine

Bullseye, if you intend to use a PC as a sorce, why do you need DEQ? You can do all equalization using Foobar's VST-plugins.

Well this question comes a bit late. I bought around a month ago the DEQ2496.

I need the DEQ because it has an excellent DAC. The sound card from my laptop is bad, and doesn't have optical output. I use an external one now with optical output.

Then also because right now I can't use a headphone system, but as soon as I can I will be buying some speakers and will treat my room according to the system. If I want a room to sound good I need proper equalization. If i can use it as a DAC with Headphones and an EQ with speakers I will be spending less money than buying separately.

[gilency]

Bullseye. You mention the DAC in the DEQ2496 as being excellent. I could not find information as to what kind it uses. How do you think it compares with more expensive, dedicated DACs? I am mainly interested in the equalizer feature and in playing with all the digital features.

[Bullseye]

Hey gilency,

The info I have over the DEQ2496 is here:

Google Translate

Original here: Matrix-HiFi --> Test Behringer DEQ2496


Hope it helps

[gilency]

Thank you Bullseye. Very interesting. Now I need to find me a used one at a decent price.