Would Dirac really help me cure my room's acoustic problems?

[twist222]

Does anyone know if the calibration file that comes with the Earthworks mics is based on (1) the mic pointing at the source or (2) the mic pointing at 90 degrees to the source ie at the ceiling ?

 

Regards

Mark

[nununo]

Nuno's UMIK-1 features a 0° calibration file so I think that it should be used horizontally.

(the same mic can be purchased with a 90° calibration but at an additional cost i.e. from Cross Spectrum Labs)

 

Hi Flavio,

 

Thanks for that info. I didn't know that. I didn't find this information anywhere. Where is it stated?

 

Regards,

Nuno

[nununo]

Flavio, on the forward spots, should the microphone also go forward (thus, closer to the speakers) a minimum of 50cm? Thanks.

[flak]

 

Separately, there is quite a bit of debate as far as what frequencies you want to correct. Many argue that DRC is only useful in correcting the bass frequencies. I would argue that this is not entirely correct, but correcting anything higher than standing waves is relatively difficult compared to basic sub correction.

 

.

 

Hi alexwgoody,

 

I'm quoting this sentence of yours which is in accordance with the following post from Dirac's Jakob explaining some relevant aspects:

 

"Mathematically it is possible to correct a room, perfectly, in a single point. For this case, only a single measurement in that single point is needed, and also any additional measurements will indeed not contribute at all, and if used, they will ruin the result in that one point.

 

However, it is important to note the conditions for this to be true. A single point indeed means just that, a single point, with point meaning a spot with no width nor height.

 

Now this is the theory, in practice we don't sit still, we move about, even if just small distances. Also we got two ears, located at different places, on average about 23 cm between them, so our ears are clearly in distinct positions. On top of this our speakers are placed in a room, introducing a multitude of reflexions. The reflected sound will arrive in different points in time, with different amplitude, to each ear, so at any moment in time the sound will not be the same in these two positions. In the attached image two different measurements are shown, with the distance between them being roughly 30cm. Now, which one to chose if I can have only one?

 

 

Any solution trying to adress these issues is a compromise. Completely predicting the reflexion patterns is impossible with a small number of measurements, so an educated guess will have to do. The information used come from measurements in and around the measurement position. If you only have a single point you are effectively guessing what the result will be at your two ears. More often than not, your guess will be incorrect because the wave pattern, especially at mid and high frequencies, is fundamentally impossible to predict. When we take several measurements, our guesses about what's going on in between these positions, become better and better. As a rule of thumb, it becomes easier to predict the behavior in nearby positions the lower the frequency is, and vice versa. That's why a subwoofer correction can work OK in most cases even if just based on a single measurement, whereas a high-performance full-bandwidth optimization require more measurements in order to guarantee that we don't end up mistakenly making things worse at some frequencies. The real problem in room correction is to make the best possible estimate of what can be corrected and what can't. You need several measurements to do a good job at that.

 

More information about the Dirac Live Room Correction, and on why using mutliple points of measurements is actually a good idea can be found at: http://www.dirac.se/media/12044/on_room_correction.pdf"

 

b.t.w. it also agrees with Dallasjustice's remark about the relevance of multipoint measurements for the success of Dirac Live's algorithm.

 

Ciao, Flavio

[flak]

Hi Flavio,

 

Thanks for that info. I didn't know that. I didn't find this information anywhere. Where is it stated?

 

Regards,

Nuno

 

I'm glad to read that forums can provide useful info

 

also it should have been stated in the webshop receipt:

 

"Microphone calibration file

If you have ordered a UMIK-1 USB Measurement Microphone, please download your unique calibration file here: http://www.dirac.se/umik-calibration-file-download.aspx. With this microphone, if making a 2-channel measurement, please point it forward towards the speakers. If making a multichannel measurement, please point it up towards the ceiling"

 

Good listening, Flavio

 

p.s. re your other question I'd say yes and use a 50 cm. distance in all directions

[Frans]

Hello Flavio,

 

You wrote "With this microphone, if making a 2-channel measurement, please point it forward towards the speakers. If making a multichannel measurement, please point it up towards the ceiling".

 

Now I'm a little bit confused. I own a XTZ Microphone Pro, must I also point this microphone forward towards the speakers when I do a 2-channel measurement? The Direc Live manual says (page 15, 2b):

 

b) Direct the microphone upward, pointing to the ceiling, to

get the most omnidirectional recording of the room

response.

 

Please help!

 

Thanks in advance,

 

Frans

[nununo]

Thank you Flavio.

 

Actually I did read that but misunderstood it: I confused 2-channel measurement with the chair mode and multichannel measurement with the sofa mode. Silly, but that's what happened. Thus my confusion. Now things are clear.

 

Thanks again.

 

Nuno

[flak]

Hello Flavio,

 

You wrote "With this microphone, if making a 2-channel measurement, please point it forward towards the speakers. If making a multichannel measurement, please point it up towards the ceiling".

 

Now I'm a little bit confused. I own a XTZ Microphone Pro, must I also point this microphone forward towards the speakers when I do a 2-channel measurement? The Direc Live manual says (page 15, 2b):

 

b) Direct the microphone upward, pointing to the ceiling, to

get the most omnidirectional recording of the room

response.

 

Please help!

 

Thanks in advance,

 

Frans

 

Hi Frans,

 

I was speaking about the UMIK-1 with 0° calibration file... your XTZ microphone is calibrated to be used vertically, so point it to the ceiling

 

Ciao Flavio

[Frans]

Hi Frans,

 

I was speaking about the UMIK-1 with 0° calibration file... your XTZ microphone is calibrated to be used vertically, so point it to the ceiling

 

Ciao Flavio

 

Hello Flavio,

 

Thank a lot, now I know for sure!

Have a nice weekend!

 

Frans

[AnotherSpin]

If you have ordered a UMIK-1 USB Measurement Microphone, please download your unique calibration file here: http://www.dirac.se/umik-calibration-file-download.aspx.

 

Dear Flavio,

 

I used a calibration file from miniDSP site when I made initial IRC measurements and created filters. Now, after your suggestion I did everything again using file from dirac site. Additionally to usage of dirac calibration file I directed a mic toward speakers, while initially it was directed vertically. Now, there is a clear difference. In comparison to initial result the new sound has more bottom, but, the voices sound slightly muddy in comparison. Separation of the instruments not so good. The picture is not so clear. The bottom line is: I prefer filter created with miniDSP calibration file / ceiling direction versus dirac file / speakers direction. But, I still want to go deeper with this - maybe I missed something? Also, the distances I used for sofa filter are 40 cm from sweet spot to first two and then additional 40 cm to second two.

 

Please comment.

[AnotherSpin]

It related to Amarra with iRC

[flak]

Dear Anotherspin,

 

let me first say that there is no difference between the calibration file from Dirac site or from miniDSP site, they are the same 'cause the calibration file is unique to your individual microphone and it is provided by miniDSP.

Now let's comment the differences that you have heard when changing the direction of the microphone... the frequency response of the mic does not change at the low and mid frequencies while it changes at the high frequencies.

You can evaluate those differences by clicking the following link where a UMIK-1 microphone has been measured both at 0°, 45° and 90° degrees:

http://www.cross-spectrum.com/cslmics/700-0589_mic_report.pdf

 

This explains the differences that you have heard which are clearly attributable to the different response at the high frequencies, even if it may be perceived as a difference in other sound qualities.

So there is no problem, you can alternatively adjust your target curve, or if you prefer you can use your microphone vertically... as you can see from the measurements page that I have linked there is a slight and gently sloping boost of the high frequencies when you measure vertically.

 

Good listenings

Flavio

[AnotherSpin]

Thank you!

[skatbelt]

Hello, does anybody know if I can use the Lyngdorf roomperfect calibration microphone with Dirac Live or Amarra with IRC? I am curious how these products compare to my Lyngdorf solution. I do also own a TASCAM US 122 MKII that can act as a microphone pre-amp.

 

In my listening environment, digital room correction has makes a huge difference. Although it is not the holy grail, I can not imagine living without it. Careful speaker placement and some acoustic measures (especially against first reflections) stay important.

[flak]

Hi Skatbelt,

 

you can use any measurement microphone as long as....

guess what

 

it is a measurement microphone,

(you have its full bandwidth individual calibration file and you know if it has to be used horizontally or vertically)

 

So even if I do not know it I expect that you can use the microphone that is supplied with Lyngdorf's RP without problems.

 

Ciao, Flavio

 

P.S. there could be a minor modification to be done to the calibration file if it reports the correction to be applied instead of the actual frequency response... let me know if this is the case

[MikeJazz]

Hi Skatbelt,

 

you can use any measurement microphone as long as....

guess what

 

it is a measurement microphone,

(you have its full bandwidth individual calibration file and you know if it has to be used horizontally or vertically)

 

So even if I do not know it I expect that you can use the microphone that is supplied with Lyngdorf's RP without problems.

 

Ciao, Flavio

 

P.S. there could be a minor modification to be done to the calibration file if it reports the correction to be applied instead of the actual frequency response... let me know if this is the case

 

Gents,

 

the Lyngdorf microphone is directly connected to the TDAi or RP "machine"...with a minijack...

I believe you need to connect via USB to work with Dirac.

 

If I can use with an adapter, I will be also interested in testing Dirac...

[flak]

Hi MikeJazz and Skatbelt,

 

as I said I do not know which microphone has Lyngdorf selected but from the only drawing that I could find it looks like it can be a condenser microphone similar to a Behringer ECM 8000, the right source of info is Lyngdorf itself so an email to them would certainly be useful.

 

If that is the case and you have access to an audio card with a phantom power supply like Skatbelt's Tascam you can connect it to that (the audio card is then connected to the computer via USB)

 

Finally there is the calibration file issue... does the microphone have a calibration file?

 

Ciao, Flavio

[skatbelt]

Hi MikeJazz and Skatbelt,

 

as I said I do not know which microphone has Lyngdorf selected but from the only drawing that I could find it looks like it can be a condenser microphone similar to a Behringer ECM 8000, the right source of info is Lyngdorf itself so an email to them would certainly be useful.

 

If that is the case and you have access to an audio card with a phantom power supply like Skatbelt's Tascam you can connect it to that (the audio card is then connected to the computer via USB)

 

Finally there is the calibration file issue... does the microphone have a calibration file?

 

Ciao, Flavio

 

Hi Flavio,

 

Thanks you for your answers. I will give it a try with a trial version of Dirac live (and/or Amarra Symphony with iRC). Lyngdorf did not give information other than that their microphone is especially calibrated for their hardware. Is there a way to test if it has a acceptable flat response? Maybe with REW and a near field sweep or something?

 

Grtz,

Sander

[flak]

Hi Sander,

 

if Lyngdorf does not provide an individual calibration file they probably use a generic profile of that mic... it would be great if they would give it to you 'cause the alternative is to have your microphone calibrated at a cost.

 

Another option is to buy a USB microphone like this:

Dirac Online Store. UMIK-1 USB Measurement Microphone

(because the mic preamp is built in you do not need an audio card and the calibration takes the preamp into account also)

 

By using a microphone without its calibration file (and an individual one if possible) you will certainly get an idea of how Dirac Live works but the results will be unreliable and probably unsatisfactory.

 

Ciao, Flavio

[Nightmare]

Unfortunately this thread found a sudden death in December without any final feedback of nununo as the thread opener. I would be very interested in reading about the results of the Dirac trial. Also Chuck's further findings concerning Dirac vs Amarra Symphony iRC might be worth posted here?!

[nununo]

Hello,

 

Sorry about my silence.

 

I did test Dirac. On the positive side and found that it does greatly improve the sound's focus. But I ended up not buying it for 2 reasons:

 

1. Dirac is not compatible with A+ integer mode (due to the way it integrates with other programs). And having compared both Dirac + normal A+ against A+ with integer mode I found that, even though I could objectively notice Dirac's improvements, I definitely found that I found the sound form A+ must more enjoyable and compelling. As much as objective improvements are important, for me, in the end, it boils down to how much enjoyment I get from listening to the music. And I found that through A+ integer mode I feel like sitting there and listening.

 

2. I found Dirac's interface to still be a little buggy. And it being an extra piece of software which I'd always have to have loaded, if it is to be there I want it to be smooth enough for me to be able to forget about it.

 

So, since I still have so many other things to improve (power cables, interconnects, MacMini fine-tuning, etc.), and since things are evolving so quickly, I decided to postpone my concerns with room correction and focus on these other things first.

 

This said, I didn't give up on Dirac forever. But I'll wait and see how things evolve. I don't even know if in six months I'll still be using a Mac Mini as my audio source. Auralic Aries is about to be revealed and it looks promising. And it is supposed to include room correction at some point.

 

Regards,

Nuno

[Nightmare]

Thanks for your reply. I appreciate it.

 

I think it always depends on the room. The more issues you have to be solved, the more benefit might be obvious. Of course DRC produces negative effects also. I will try Amarra Symphony iRC, also. Maybe a better way to solve rising problems after room correction. I dont know yet.

 

With A+ you mean Audirvana plus, dont you?!

 

What do you mean with "it has always to be loaded"? Cant you put it into the autostart section and doesnt it start with the Mac mini automatically when the Mac mini wakes up from deepsleep?

 

I will test it with Amarra (HiFi) and compare it with Amarra Symphony iRC soon.

[Nightmare]

Didn't you have droning bass due to room issues? You will not solve that problem by power cables, interconnects or MacMini fine-tuning, etc. at all as you mentioned?!

[nununo]

Yes, by A+ I mean Audirvana Plus.

 

By "it has always to be loaded" I meant that besides loading Audirvana I'd have to load Dirac. I know it can automatically be loaded on startup. Given its nature (not needing frequent user interaction), it could have been designed as a background service with an optional configuration interface which you'd only load when needed. But no, it is always an interactive application with a window you cannot get rid of. Still, if it weren't for the A+ limitations and the fact that the interface is not without bugs, probably I wouldn't care about this.

 

Fortunately I don't have bass issues in my room because my JL Audio F112 subwoofer has its own room correction which took care of that

 

Cheers,

Nuno

 

[flak]

By "it has always to be loaded" I meant that besides loading Audirvana I'd have to load Dirac. I know it can automatically be loaded on startup. Given its nature (not needing frequent user interaction), it could have been designed as a background service with an optional configuration interface which you'd only load when needed. But no, it is always an interactive application with a window you cannot get rid of.

 

Hello Nuno

 

as you say it's no big deal but actually Dirac Live can be loaded at startup and work in the background... if you close the window the DAP (Dirac Audio Processor) will keep working but to access it, and view the window, you will have to click on the small icon in the tray down to the bottom right.

 

Ciao, Flavio