# Chance of adding an additional free bell filter to GLM2 - Forum

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## Keskusteluryhmät

### Chance of adding an additional free bell filter to GLM2

##### jantex, muokattu 7 Vuodet sitten.

#### Chance of adding an additional free bell filter to GLM2

Padawan Viestejä: 36 Liittymispäivä: 11.3.2015 Viimeisimmät viestit##### ilkka-rissanen, muokattu 7 Vuodet sitten.

#### Re: Chance of adding an additional free bell filter to GLM2

Yoda Viestejä: 2564 Liittymispäivä: 23.3.2009 Viimeisimmät viestitThe amount of available DSP processing time is hardware, not software dependant. So adding more available filters would require a DSP processor change which is not an easy task to do. Our newer monitor models such as 8320, 8330, 8340, 8350 have more processing power and filters available.

edit: See the table below for more accurate information.

##### jantex, muokattu 7 Vuodet sitten.

#### Re: Chance of adding an additional free bell filter to GLM2

Padawan Viestejä: 36 Liittymispäivä: 11.3.2015 Viimeisimmät viestitWhat about this solution. We have two HI SHELF filters available in GLM for 8351. One can only be used for cutting while the other can also be used for boosting. And these filters are not used by AutoCal. It would be great if we had an option to choose for one of these shelving filters to be bell or shelf.

##### elsapo2001, muokattu 6 Vuodet sitten.

#### RE: Re: Chance of adding an additional free bell filter to GLM2

Youngling Viestejä: 19 Liittymispäivä: 3.10.2017 Viimeisimmät viestitjantex:Hi, so does the monitors you mentioned have 5 times the amount of processing power compared to the 82XX series or did you mean compared to 8351, which also belong to 83XX family? In case 8350 have five time the processing power of 8351 it is a pretty sad news for the owners of 8351 which are much more expensive monitors, but currently couldn't match 8350 with regards to max SPL and processing power. Having five times more available filters can really improve monitoring in critical rooms and frequency areas so much more.

What about this solution. We have two HI SHELF filters available in GLM for 8351. One can only be used for cutting while the other can also be used for boosting. And these filters are not used by AutoCal. It would be great if we had an option to choose for one of these shelving filters to be bell or shelf.

Simple, technology marches forward in dog years. The 8351 is still a better speaker than the 8050 even if it has the newer ASIC chip that did not exist when the 8351 was developed. Have you thought of doing the corrections with a dedicated parametric EQ for your 8351s? I have a dedicated parametric EQ for room correction where I corrected some problem frequencies in my treated room, it works really well If you do it that way you dont have to use up one of your DSP filters and you get more flexibility.

##### ilkka-rissanen, muokattu 6 Vuodet sitten.

#### Re: Chance of adding an additional free bell filter to GLM2

Yoda Viestejä: 2564 Liittymispäivä: 23.3.2009 Viimeisimmät viestitHi, so does the monitors you mentioned have 5 times the amount of processing power compared to the 82XX series or did you mean compared to 8351, which also belong to 83XX family? In case 8350 have five time the processing power of 8351 it is a pretty sad news for the owners of 8351 which are much more expensive monitors, but currently couldn't match 8350 with regards to max SPL and processing power. Having five times more available filters can really improve monitoring in critical rooms and frequency areas so much more.

The amount of filters is not the same between all models within the same series. DSP processors are updating all the time which means that typically newer models have more processing power available. Obviously we use platforms which means that a certain design is used in multiple models.

Here is a quick table shoving the available filters in different models.

**Monitors**

8240, 8250: 4 notch + 4 shelving

8351, 8260, 1238CF/DF, 1237A, 1238A, 1238AC, 1234A, 1234AC, 1236A: 6 notch + 4 shelving

8320, 8330, 8340, 8350, 8331, 8341: 16 notch + 4 shelving

**Subwoofers**

SE system, 7261: 2 notch + 2 shelving

7260, 7270, 7271: 4 notch

7350, 7360, 7370, 7380: 20 notch

##### daiyama, muokattu 7 Vuodet sitten.

#### Re: Chance of adding an additional free bell filter to GLM2

Padawan Viestejä: 73 Liittymispäivä: 4.1.2016 Viimeisimmät viestitWhat was yesterday "state of the art" is tomorrow only "medicore".

But luckily the 8351 will still sound great tomorrow.

But to be honest I was also a bit dissapointed to learn that there are only six notch and 4 shelve filters and in my settings two or three of the shelve are not uswd at all.

A little bit more flexibility between notch and shelve filter would be nice, though I do not know if notch and shelve filter require similar processing power, propably not.

##### jantex, muokattu 7 Vuodet sitten.

#### Re: Chance of adding an additional free bell filter to GLM2

Padawan Viestejä: 36 Liittymispäivä: 11.3.2015 Viimeisimmät viestitHi, so does the monitors you mentioned have 5 times the amount of processing power compared to the 82XX series or did you mean compared to 8351, which also belong to 83XX family? In case 8350 have five time the processing power of 8351 it is a pretty sad news for the owners of 8351 which are much more expensive monitors, but currently couldn't match 8350 with regards to max SPL and processing power. Having five times more available filters can really improve monitoring in critical rooms and frequency areas so much more.

The amount of filters is not the same between all models within the same series. DSP processors are updating all the time which means that typically newer models have more processing power available. Obviously we use platforms which means that a certain design is used in multiple models.

Here is a quick table shoving the available filters in different models.Monitors

8240, 8250: 4 notch + 4 shelving

8351, 8260, 1238CF/DF, 1237A, 1238A, 1234A, 1236A: 6 notch + 4 shelving

8320, 8330, 8340, 8350: 16 notch + 4 shelvingSubwoofers

SE system: 2 notch + 2 shelving

7260, 7270, 7271: 4 notch

7350, 7360, 7370: 20 notch

Ilkka, so what does in your opinion then make 8351 a better speaker worth the significant price difference since

8350 are able to produce higher SPL with flatter response (only +/- 1dB measured deviation in anechoic conditions compared to +/-1,5 dB of 8351), and besides they also have much more processing power? I would like to apologise in case my question might sound slightly provocative, but it is not and I would really like to know this.

I know 8351 is three way compared to 8350 which are two way speakers, but does it bring anything else to the table apart from higher cost? I have and love 8351, but with more powerful DSP section and better published specs (higher SPL and flatter response) I am wondering whether 8350 migh be even better option for much lower price?

##### ilkka-rissanen, muokattu 7 Vuodet sitten.

#### Re: Chance of adding an additional free bell filter to GLM2

Yoda Viestejä: 2564 Liittymispäivä: 23.3.2009 Viimeisimmät viestitI think you are overly underestimating the benefits of a true 3-way design in the 8351. That alone makes it sound completely different from 8350 or any other 2-way monitor. When it comes to the specification race, they are basically the same when it comes to SPL (1 dB here and there won't make any difference and it is an average between 100 Hz to 3 kHz anyway), frequency response flatness is identical +/- 1.5 dB (we had error on website, sorry about that). Only large difference is the amount of free notch filters (AutoCal uses maximum of 6 notch filters on both) which may help to achieve slightly flatter in-room response is very difficult acoustical environments. But having said that, I do not recommend changing your speakers to 8350 because that would be considered serious downgrading and you would probably miss the sound quality and superior imaging of the 8351.

##### audiounit, muokattu 7 Vuodet sitten.

#### Re: Chance of adding an additional free bell filter to GLM2

Youngling Viestejä: 18 Liittymispäivä: 29.6.2010 Viimeisimmät viestitIs there anyway to to use the DSP for the Shelving EQ's to add Notch filters as they are much more useful so possibly have 8 notch and 2 shelving or even just 10 notch. I don't use the shelving eq's at all, it would be of a great benefit to me and i'm shore to others to be able to choose where those DSP resources are allocated.

For example have the standard 10 filters and the ability to choose between shelving and notch by clicking on the icon and swapping them out that way they DSP limitations are kept in tact. Similar to standard parametric eq, this would be really helpful to me if this where some that could be implemented

I love my 8351 but the limited amount of filters is frustrating.

##### dimoroc, muokattu 7 Vuodet sitten.

#### Re: Chance of adding an additional free bell filter to GLM2

Padawan Viestejä: 33 Liittymispäivä: 18.1.2016 Viimeisimmät viestit##### elsapo2001, muokattu 6 Vuodet sitten.

#### RE: Re: Chance of adding an additional free bell filter to GLM2

Youngling Viestejä: 19 Liittymispäivä: 3.10.2017 Viimeisimmät viestitdimoroc:I'm very interested as well in what the 8351 brings to the table warranting the price difference, giving the fact that the specs give edge to the new 8350.

I think the trouble with specs is they dont tell the whole story you have to test drive them to determine the differences and if they work for you. I ended up replacing all my monitors with Genelecs because I tested a pair and it was a big improvement over what I have been using. I did not even look at spec sheets :)

Now family members have really nice expensive studio monitors for thier home hifi's and tv sets that left my studio :)

##### jantex, muokattu 7 Vuodet sitten.

#### Re: Chance of adding an additional free bell filter to GLM2

Padawan Viestejä: 36 Liittymispäivä: 11.3.2015 Viimeisimmät viestitHi,

I think you are overly underestimating the benefits of a true 3-way design in the 8351. That alone makes it sound completely different from 8350 or any other 2-way monitor. When it comes to the specification race, they are basically the same when it comes to SPL (1 dB here and there won't make any difference and it is an average between 100 Hz to 3 kHz anyway), frequency response flatness is identical +/- 1.5 dB (we had error on website, sorry about that). Only large difference is the amount of free notch filters (AutoCal uses maximum of 6 notch filters on both) which may help to achieve slightly flatter in-room response is very difficult acoustical environments. But having said that, I do not recommend changing your speakers to 8350 because that would be considered serious downgrading and you would probably miss the sound quality and superior imaging of the 8351.

Thank you, Ilkka, this is a response I wanted to hear

But I agree with opinion of another user. It would be great if we had 8 notch and 2 shelving filters or a chance for 2 out of 4 shelving filters to change them to notch filters.

##### daiyama, muokattu 7 Vuodet sitten.

#### Re: Chance of adding an additional free bell filter to GLM2

Padawan Viestejä: 73 Liittymispäivä: 4.1.2016 Viimeisimmät viestit##### ilkka-rissanen, muokattu 7 Vuodet sitten.

#### Re: Chance of adding an additional free bell filter to GLM2

Yoda Viestejä: 2564 Liittymispäivä: 23.3.2009 Viimeisimmät viestitHi Ikka,

Is there anyway to to use the DSP for the Shelving EQ's to add Notch filters as they are much more useful so possibly have 8 notch and 2 shelving or even just 10 notch. I don't use the shelving eq's at all, it would be of a great benefit to me and i'm shore to others to be able to choose where those DSP resources are allocated.

For example have the standard 10 filters and the ability to choose between shelving and notch by clicking on the icon and swapping them out that way they DSP limitations are kept in tact. Similar to standard parametric eq, this would be really helpful to me if this where some that could be implemented

I love my 8351 but the limited amount of filters is frustrating.

Hi,

I am sorry to say but this kind of change would require such major modifications to both hardware and software that it is not practical to implement at this point. And also we are bringing a new software feature in GLM 2.0.7 which requires the shelving filters.

##### ilkka-rissanen, muokattu 7 Vuodet sitten.

#### Re: Chance of adding an additional free bell filter to GLM2

Yoda Viestejä: 2564 Liittymispäivä: 23.3.2009 Viimeisimmät viestitWhen I understand Ilkkas comment correct, the limiting factor does not seem to be the speakers, it is the GLM software which uses at the moment allways 6 notch filters.

I think you understood it slightly wrong. AutoCal algorithm is designed to use a maximum of number of 6 notch and 2 LF shelving filters for monitors and 12 notch filters for the subwoofers. The amount of available filters differs from model to model which is limited by the hardware (DSP processing power and platform) as listed a few posts back.

##### kirma, muokattu 6 Vuodet sitten.

#### RE: Re: Chance of adding an additional free bell filter to GLM2

Youngling Viestejä: 20 Liittymispäivä: 5.5.2017 Viimeisimmät viestitCan adding extra filters, high-Q or not, cause audible adverse effects on sound quality? I'm playing with my new (purely pleasure, not business) 8341As and find the approach AutoCal limits itself to a bit puzzling. I understand using parametric notch filters above 2 kHz can cause sub-optimal results due to limitations of DSP algorithm implementation, but how about other possible effects? Can you provide any psychoacoustic advice, for instance on (over)fitting these 16+4 filters to the unfiltered frequency response?ilkka-rissanen:When I understand Ilkkas comment correct, the limiting factor does not seem to be the speakers, it is the GLM software which uses at the moment allways 6 notch filters.

I think you understood it slightly wrong. AutoCal algorithm is designed to use a maximum of number of 6 notch and 2 LF shelving filters for monitors and 12 notch filters for the subwoofers. The amount of available filters differs from model to model which is limited by the hardware (DSP processing power and platform) as listed a few posts back.

##### ilkka-rissanen, muokattu 6 Vuodet sitten.

#### RE: Re: Chance of adding an additional free bell filter to GLM2

Yoda Viestejä: 2564 Liittymispäivä: 23.3.2009 Viimeisimmät viestitCan adding extra filters, high-Q or not, cause audible adverse effects on sound quality? I'm playing with my new (purely pleasure, not business) 8341As and find the approach AutoCal limits itself to a bit puzzling. I understand using parametric notch filters above 2 kHz can cause sub-optimal results due to limitations of DSP algorithm implementation, but how about other possible effects? Can you provide any psychoacoustic advice, for instance on (over)fitting these 16+4 filters to the unfiltered frequency response?ilkka-rissanen:When I understand Ilkkas comment correct, the limiting factor does not seem to be the speakers, it is the GLM software which uses at the moment allways 6 notch filters.

I think you understood it slightly wrong. AutoCal algorithm is designed to use a maximum of number of 6 notch and 2 LF shelving filters for monitors and 12 notch filters for the subwoofers. The amount of available filters differs from model to model which is limited by the hardware (DSP processing power and platform) as listed a few posts back.

Hi Jari,

Of course you can test different calibrations by adding manual filters but you should be careful when doing this. Currently AutoCal algorithm is allowed to place one notch filter above 1 kHz but below 3 kHz with a Q value between 0.5 and 1.2. Using high Q value filters at high frequencies is not recommended because due to the short wavelenghts involved, corrections would be very local. Also, this can introduce sudden phase shifts at a region where our hearing is very sensitive. Corrections in this range are typcially best to be made symmetrical between left and right speaker pairs to ensure good stereo imaging and voicing.

##### kirma, muokattu 6 Vuodet sitten.

#### RE: Re: Chance of adding an additional free bell filter to GLM2

Youngling Viestejä: 20 Liittymispäivä: 5.5.2017 Viimeisimmät viestitIlkka Rissanen:Jari Kirma:Can adding extra filters, high-Q or not, cause audible adverse effects on sound quality? I'm playing with my new (purely pleasure, not business) 8341As and find the approach AutoCal limits itself to a bit puzzling. I understand using parametric notch filters above 2 kHz can cause sub-optimal results due to limitations of DSP algorithm implementation, but how about other possible effects? Can you provide any psychoacoustic advice, for instance on (over)fitting these 16+4 filters to the unfiltered frequency response?ilkka-rissanen:

I think you understood it slightly wrong. AutoCal algorithm is designed to use a maximum of number of 6 notch and 2 LF shelving filters for monitors and 12 notch filters for the subwoofers. The amount of available filters differs from model to model which is limited by the hardware (DSP processing power and platform) as listed a few posts back.Hi Jari,

Of course you can test different calibrations by adding manual filters but you should be careful when doing this. Currently AutoCal algorithm is allowed to place one notch filter above 1 kHz but below 3 kHz with a Q value between 0.5 and 1.2. Using high Q value filters at high frequencies is not recommended because due to the short wavelenghts involved, corrections would be very local. Also, this can introduce sudden phase shifts at a region where our hearing is very sensitive. Corrections in this range are typcially best to be made symmetrical between left and right speaker pairs to ensure good stereo imaging and voicing.

Sounds like there's indeed lots to consider, and to possibly mess up when doing it myself.

What are the chances of GLM using more than 2+6 filters in a future, or the cloud version? It sounds like expertise on curve fitting would be best left to Genelec software, but at the moment it doesn't really take advantage of extra filters, and for instance, I see clear underpresentation of treble on the plot in my environment (which is waiting for light acoustic treatment, I must admit). I'm a little surprised it hasn't been compensated automatically.

On basis of what was said above, it's clearly not sensible to fit notch filters with Q=20 (which these filters support) at least with high attentuations on frequency response curve "bumps" filtered to the level where such features are visible. What is a level of smoothing would be sensible target for fitting in order not to shoot myself in the foot by side effects? 1/3 octave window (or Bark scale bands), or even wider?

##### ilkka-rissanen, muokattu 6 Vuodet sitten.

#### RE: Re: Chance of adding an additional free bell filter to GLM2

Yoda Viestejä: 2564 Liittymispäivä: 23.3.2009 Viimeisimmät viestitWould it be possible to send your setup file (Help | Export setup to desktop) so that I can take a look? My email is firstname.lastname@genelec.comIlkka Rissanen:Jari Kirma:ilkka-rissanen:

I think you understood it slightly wrong. AutoCal algorithm is designed to use a maximum of number of 6 notch and 2 LF shelving filters for monitors and 12 notch filters for the subwoofers. The amount of available filters differs from model to model which is limited by the hardware (DSP processing power and platform) as listed a few posts back.Hi Jari,

Of course you can test different calibrations by adding manual filters but you should be careful when doing this. Currently AutoCal algorithm is allowed to place one notch filter above 1 kHz but below 3 kHz with a Q value between 0.5 and 1.2. Using high Q value filters at high frequencies is not recommended because due to the short wavelenghts involved, corrections would be very local. Also, this can introduce sudden phase shifts at a region where our hearing is very sensitive. Corrections in this range are typcially best to be made symmetrical between left and right speaker pairs to ensure good stereo imaging and voicing.

Sounds like there's indeed lots to consider, and to possibly mess up when doing it myself.

What are the chances of GLM using more than 2+6 filters in a future, or the cloud version? It sounds like expertise on curve fitting would be best left to Genelec software, but at the moment it doesn't really take advantage of extra filters, and for instance, I see clear underpresentation of treble on the plot in my environment (which is waiting for light acoustic treatment, I must admit). I'm a little surprised it hasn't been compensated automatically.

On basis of what was said above, it's clearly not sensible to fit notch filters with Q=20 (which these filters support) at least with high attentuations on frequency response curve "bumps" filtered to the level where such features are visible. What is a level of smoothing would be sensible target for fitting in order not to shoot myself in the foot by side effects? 1/3 octave window (or Bark scale bands), or even wider?

##### daiyama, muokattu 7 Vuodet sitten.

#### Re: Chance of adding an additional free bell filter to GLM2

Padawan Viestejä: 73 Liittymispäivä: 4.1.2016 Viimeisimmät viestitThe new feature of the GLM software sounds exciting.

Are you able to share any news at this time?

##### ilkka-rissanen, muokattu 7 Vuodet sitten.

#### Re: Chance of adding an additional free bell filter to GLM2

Yoda Viestejä: 2564 Liittymispäivä: 23.3.2009 Viimeisimmät viestitOk, so the extra notch filters of the 8350 is only for manually editing of the EQ curve?

Yes, correct!

The new feature of the GLM software sounds exciting.

Are you able to share any news at this time?

Unfortunately not yet.

##### kwsmix, muokattu 6 Vuodet sitten.

#### RE: Re: Chance of adding an additional free bell filter to GLM2

Youngling Viestejä: 2 Liittymispäivä: 30.9.2017 Viimeisimmät viestitHello. I found this thread through Google. Is this in the current release of GLM? Thanks.ilkka-rissanen:Ok, so the extra notch filters of the 8350 is only for manually editing of the EQ curve?

Yes, correct!

The new feature of the GLM software sounds exciting.

Are you able to share any news at this time?

Unfortunately not yet.