DSP speakers - any new functions for GLM planned ? - Forum

Dear Andreas,

The GLM measuring system uses state-of-the art technique to measure the overall response of the loudspeaker in-situ. This means it takes the complex speaker-room interaction in account and calibrate each loudspeaker to retrieve flat and balanced frequency response whatever the room you are in.

The RT60, waterfall analysis, Schroeder filter curves, etc are all post-processing info of a single impulse response measurement you can take with MLSSA or WinMLS for example. GLM generates this impulse response measurement, processes the data and applies the best parameters to each loudspeaker as explained before. GLM is not a measuring system that would provide such post-processing info. It is a powerful Loudspeaker Manager software.

So, first I would encourage you to use your new GLM, calibrate all your speaker systems and then perform a careful listening test. The use of extra Eq should be considered very carefully, especially having properly setup and calibrated your system thanks to GLM AutoCal.

Best regards,

That is all true Christophe, and I do not have a single doubt about the quality of what GLM does, but I would rather prefer to simplify to one measuring system, and as GLM comes with a calibrated microphone, it would be great to see where I can improve my room. That is by analysing waterfall and impuls in datails. Why would it be too much to ask to be able to switch through one or two more graphs in GLM. A waterfall should be pretty easy to programm ? To generate different test signals may require more work to the software in the speakers ? Something like that :



So I assume there are no current further plans.

Something else then. Would it be possible to get the correction data for the particular microphone number that I get with the bought GLM ? Maybe there is a chance to import that data into REW (room eq wizzard) for mic correction ?

Dear Christophe,
my GLM 1.2 arrived today and the install and first use was as easy as expected with the 8240ties, ending in standalone operation. Questions :

1) can I copy the frequency responce somehow to a clipboard in Wondows and covert to BMP or JPEG ? I know I can always copy by using the Hardcopy tool (screen copy), but cannot see any copy function to JPEG or BMP in GLM ? Maybe I have overlooked something in the rush of excitement ?

2) I will register my unit later on. Can you pls share more details what the serial number of the mic offers/means ? Is there really a correction curve associated with the serial number of the mic ? Say my mic would be 100960, could you tell me the correction values ? I still hope to use the mic for room eq wizzard as well, the value return of the 600 Euro spent for GLM would be even greater . Thx alot.

Dear Christophe,
my GLM 1.2 arrived today and the install and first use was as easy as expected with the 8240ties, ending in standalone operation. Questions :

1) can I copy the frequency responce somehow to a clipboard in Wondows and covert to BMP or JPEG ? I know I can always copy by using the Hardcopy tool (screen copy), but cannot see any copy function to JPEG or BMP in GLM ? Maybe I have overlooked something in the rush of excitement ?

Dear Andreas,

Unfortunately GLM doesn't offer that kind of exporting options, so you will have to use an external program if you want to take a screen shot of the frequency response etc. Of course we could consider adding an option for future SW release if there's enough requests.

2) I will register my unit later on. Can you pls share more details what the serial number of the mic offers/means ? Is there really a correction curve associated with the serial number of the mic ? Say my mic would be 100960, could you tell me the correction values ? I still hope to use the mic for room eq wizzard as well, the value return of the 600 Euro spent for GLM would be even greater . Thx alot.

Use the Windows search for filename "Genelec8200A100960.txt". That file contains the calibration data for your microphone. If you would like to use that data in Room EQ Wizard, you need to do the following:

1) Reverse the sign of every value in "correction" column
2) Change the file extension from .txt to .cal
3) Load the microphone calibration file in REW

If this sounds too complicated, please email me the calibration data file for your microphone, and I will prepare the file for you. I'll PM you my email address.

Hi Ilkka, that is excellent advice.

Yes, I think the option to copy the frequency curves out of GLM should be there, also to have 3 small flags that can be checked or not, so one can separate the 3 curves and just copy an individual line, so either the speaker, or GLM, or the eventual response curve of both together. This will help also user discussions in here, on where to improve the room or discover any other problems in reproduction.

On the conversion of the mic file to REW, I will give it a try, found the mic file easy, and if not successfull in transfer, I will come directly back to you for help

So far the first measurement (single point), already disclosed what I feared and knew by room dimensions (25m2) and other test signal sources (AVIA DVD). I have a nice ca. 35Hz room mode (+22db...shxx) and some harmonics Fortunately due to close to wall installation in my living room, the overall bass room gain, allows for dsp compensation without too big dips left stealing alot of bass that cannot be compensated. However, I would love to see the waterfall, how long the room modes need for decay. A nice Helmholtz resonator comes to mind and I even have one corner free for such a device, once I'm sure (never build one) how to tune it to 35Hz

Here are some 1/3rd smoothed slides, also some nasty stuff around 400 to 500Hz.

Left - main room mode roughly at ca. 35 Hz, Harmonics at roughly 70Hz, and 100Hz.


Right - main room mode roughly at ca. 35 Hz, almost no harmonics.....hmmmm...strange, 400 to 500Hz peak

Andreas,

Thank you for sharing the measurements. Your room certainly has some strong modes in the bass region, although very common for most non acoustically treated rooms. The AutoCal has done a good job in smoothing those peaks. How does it sounds when compared to bypass mode?

Either the speaker placement or room construction must not be identical when it comes to L & R speakers because of different mode distribution.

The ~400 Hz peak could be either a floor or a ceiling reflection. Can you share a picture/drawing of your setup?

Thanks!

Hi Ilkka,

the sound difference is really astonishing with GLM activated. The graphs alone already tell you and anyone the dramatic difference. And of course is not only the bass that has become more balanced and tighter, it is the phantom source capability as well, that is cutting out voices and nailing them into the middle between the speakers and rendering their details and tones.

The funny thing is, in the last Genelec survey in that I participated, I mentioned that phantom source reproduction was lacking in most monitors I knew when compared to coaxial reference products, especially my own prefered reference the Geithain monitors (906-901K). And now Genelec comes out with MDC...hehe...what coinsidence. But I also discovered that not only the coaxial driver will help imaging, but the DSP dramatically as well (phase). So with the 8240 I'm really in phantom image heaven right now as far as my room will allow it. Incredible depth and sound that is nicely decoupled from the speakers, just tightly focused and transparent. IMHO clearly better than the analogue 8050 in what it can do.

My room is not finished yet, so I'm reluctant to post pictures The room is treated a bit, but of course not much below 60Hz or so. I have in two room corners masked rolls of hemp (German "Hanf"), usually used for house isolation. Such rolls are piled up in the two corners from floor to ceiling, that is 2,5m high piles of rolls and a diameter of 60cm or so. 35Hz however will probably smile and cut right through.

The ceiling has 3 sails of fully perforated 3mm strong wood boards (Helmholtz effect), each 1m x 2,6m in size to get rid of slap echos.

Room dimensions are roughly :

5,37m length
4,64m depth
2,52m height

Looking at lambda, and speakers placed on a shelve board on the long wall close to the wall, the room depth domitates the 35Hz room mode, so when listening the room is wider than deep. 330m/sec devided by twice the room distance will reveal lambda. (330/(4,64mx2)= 35,56Hz. Listening distance is roughly 3m from 1029center, or 3,25 from the 8240ties.

In summer the 3rd 8240 will come

REW will need some more time. I have tested two sound cards in laptops and all fall off hard below 50Hz....hmmm

Hey there, I'm trying to revive this thread with the hope to find an answer for my problem.

First I need to thank everyone who was part of the discussion here earlier. I found some realy helpful information!

I own a pair of 8240a and the GLM. Since I moved and need to messure and treat my new audio room accoustically I wonder if I was able to use the GLM Mic with an external software like REW mentioned before.

My problem is that I can't get any signal through the mic to my computer. First I tried to use the "Genelec Sound Card" as input device but its not available in RWE (or anywhere else than the GLM software). Connecting the mic to any other sound card / audio interface isnt working either.

How do I need to setup this thing to get some signal to something like RWE?

I am sure this is possible somehow!?!

Thanks,
alex

Hey there, I'm trying to revive this thread with the hope to find an answer for my problem.

Hi Alex,

Unfortunately it is not possible to use the GLM microphone or the audio interface with external measurement programs like Room EQ Wizard. For that you need generic measurement quality microphone and audio interface. Those are available in various price ranges.

What kind of acoustic measurements is needed to treat your new room? Usually it is critical to look at the few lowest room modes / standing waves, and those you can see from the GLM measurements. Mids and highs you need to control by calculating the required amount of absorption (Sabine formula) and adding some diffracting elements (the needed amount differs by taste).

Hey Ilkka

Thank you for your reply.

I wanted to measure the room to find the right choice of absorber and differs.
I am not well experienced with acoustical room optimization but I know that it is a good start to find modes and critical frequencies with a proper measurement. That’s why I wanted to have some numbers before asking for help in forums etc.

My room is pretty small. I already calculated the RT, which is .46s (1kHz) at the moment and should be at .34s when I will have installed my molleton drapery on the window-side. (.54s / .42s at 500Hz)

I took screenshots of the GLM graph some days ago, which I attach together with a small sketch of the room.

Looking at the graph: how can I see where in the room the modes are and thus where I need to place acoustical elements?

Looking at the room: Do you think there's a better way of positioning the speakers? At the moment they are close to the corners (25cm to each wall, standing on 115cm stands).

Cheers Alex

Hi,

Thank you for the sketch as well as the screenshots, very useful. You can see the room modes very clearly by looking at the peaks drawn in red colour. You can also calculate them by using an online calculator with your room dimensions.

http://www.bobgolds.com/Mode/RoomModes.htm

You can see that the theoretical calculations match up with the actual measurement extremely well.

When it comes to adding acoustic elements, have you checked for example what GIK Acoustics or RealTraps offer: http://www.gikacoustics.com/ http://www.realtraps.com/

Hey, thanks for the links. Looks interesting.

I had a chat with some acoustic guys. They thought it should be a good thing to build some superchunks in the corners and place the speakers inside them. Is it possible to integrate 8240s into a wall or a superchunk? I checked the "Monitor Setup Guide" but couldn find any info about that.

It is possible but not required to flush-mount them. Please see:

http://www.genelec.com/faq/acoustical/f ... -monitors/
http://www.genelec.com/faq/acoustical/f ... e-monitor/
http://www.genelec.fi/documents/catalog ... ochure.pdf (see page 13.)

Hey there, I'm trying to revive this thread with the hope to find an answer for my problem.

Hi Alex,

Unfortunately it is not possible to use the GLM microphone or the audio interface with external measurement programs like Room EQ Wizard.

Umm, did I miss something? I have used it and it works, just be sure you plug the glm microphone into GLM network interface "mic in" (as it normally is) and connect audio cable between GLM network interface "mic out" and your soundcard "line in" and thats it.

And if using the mic cal data in other programs (well, at least in RoomEQwizard), be sure to invert the individual mic cal data by negating the values for correct calibration effect, as someone mentioned earlier in this topic.

Hey there, I'm trying to revive this thread with the hope to find an answer for my problem.

Hi Alex,

Unfortunately it is not possible to use the GLM microphone or the audio interface with external measurement programs like Room EQ Wizard.

Umm, did I miss something? I have used it and it works, just be sure you plug the glm microphone into GLM network interface "mic in" (as it normally is) and connect audio cable between GLM network interface "mic out" and your soundcard "line in" and thats it.

And if using the mic cal data in other programs (well, at least in RoomEQwizard), be sure to invert the individual mic cal data by negating the values for correct calibration effect, as someone mentioned earlier in this topic.

Hi,

Yes you being correct! The GLM microphone and interface can be used like that with an additional sound card.

Hi

I have exactly the same issue. I'd like to use the GLM-mic with RoomEQwizard to do some measurements in order to determine how to treat my room acoustically.

Unfortunately I can't find a a "mic out" on my GLM Network Interface. I use GLM 2.0 with 8260A.
Is there a solution that doesnt incloude buying a new mic?

The GLM 2.0 USB interface device can not be used as a normal sound card for audio input to you computer. So to use the GLM microphone for other measurements than the GLM calibration, requires you to have a generic USB sound card with microphone input.

Best Regards, Markus
Genelec Oy