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Huge amount of EQ behind Genelec speakers?

folan, modified 6 Years ago.

Huge amount of EQ behind Genelec speakers?

Padawan Posts: 54 Join Date: 10/13/14 Recent Posts
Hi Ilkka,

I found this very interesting post on gearslutz, Post #148 - http://www.gearslutz.com/board/high-end ... lec-5.html

this guy claims that....

I attended a demo recently, hosted by their designer responsible for the unit, showing the new 1238A SAM monitor (large 15" 3-way "smart" DSP design). What shocked me slightly was that the speaker is designed against many classical hi-fi speaker design rules. Drivers are not chosen because they are the "best" (whatever it means) and then fitted together to make a smooth whole, but how it fits the design ideals, in this case "engineering" view of the design process.

Woofer, for example: it is a light cone high efficiency/high power handling PA driver actually, which does not go lower than 100 Hz unaided. At the low cut-off point it is fed over +10dB EQ to force it to go to 35 Hz. Midrange is an in-house 5" cone, which can not really handle much power, but survives with the efficiency boosting waveguide. There is plenty of EQing going on behind the scenes to achieve the good on paper specks. Also radiation angles etc are exemplary, which in many other designs by other respected brands are not taken care of at all.


Is this true? Are you applying huge amount of EQing to your speakers to achieve good specs and lower frequency response?
ilpomartikainen, modified 6 Years ago.

Re: Huge amount of EQ behind Genelec speakers?

Youngling Posts: 4 Join Date: 3/24/09 Recent Posts
Thank you for asking this kind of questions, which obviously trouble many readers and listeners. I try to answer.

“Speaker is designed against classical hi-fi speaker design rules.”

I may not be aware what these rules may be, but the 1238A is designed as a professional monitoring speaker, where requirements are more stringent than in most hi-fi speakers. For example, monitoring speaker shall be extremely neutral, linear, reliable, serviceable, manufactured with very tight tolerances between units and batches over the years. Any speaker of same model may be paired with any other sample, even made years apart. As the “sound” of the recording is adjusted by listening it with the monitoring speaker, the monitoring speaker must be most revealing. Actually the monitoring speaker has to be more revealing than anything else in the reproduction chain after that. This ensures that end users will not find any surprises.

“Drivers are not chosen because they are the "best"...”

This is difficult to understand. Just the contrary is true: the drivers are carefully selected to be best for the job. If good enough driver is not available, or cannot be tailored from some existing driver, it will be designed from scratch.

“Midrange is an in-house 5" cone, which can not really handle much power…”
The midrange driver is designed and manufactured in house since 1988, as there was simply not good enough midrange drivers available. Its performance and design processes were reported in AES preprint 2755, including sensitivity, distortion, power handling and compression with high levels. The claim that midrange could not handle much power is wrong. The driver was tested up to 1 kW power to make sure it is mechanically stable and reliable. The reliability track record of this driver is extremely good. It was first used in the largest monitor 1035A and since then it is used in all 3-way models down to 1037B.

“…but survives with the efficiency boosting waveguide.”
“Also radiation angles etc are exemplary, which in many other designs by other respected brands are not taken care of at all.”

Genelec created first waveguides in 1983 in the first prototypes of 1022A to control directivity and reduce cabinet edge diffraction. Since then the DCW, as we call it, has been an essential part of our designs. The role of the DCW is to match the directivity of drivers so that both on axis and off axis responses are uniform. This relates mainly to two issues: imaging is improved, as there is less diffraction from cabinet edges, and total perceived response is improved, as the room reverberant field spectrum is much closer to direct sound spectrum. To understand this we have to remember that the human perception is formed from both direct sound and reverberation. In most rooms the reverberation is more important to the perceived balance than direct sound. I take an example: a traditional two-way box system with 200 mm woofer and 25 mm tweeter and crossover at 2,5 kHz. On axis response is tailored flat with decent crossover design. If we measure this off axis, we will find that the woofer response will be falling, progressively more with off axis angle, towards 2,5 kHz, but tweeter response will stay at its on axis level right above the crossover, and starts to fall gradually around 8…10 kHz. This simply relates to the driver directivity; i.e. its radiation size related to wavelength. Converted to the total acoustic power radiated to all directions, this pattern means there will be a dip on the upper woofer band, response will go up when we move to tweeter and starts falling again. This, combined with the frequency dependent absorption of our room, will be the reverberation response spectrum we will hear. This has been, and will be, an endless source of discussion about how good or how bad certain speaker will sound.
The role of waveguide is to limit the radiation angle of a smaller driver to match that of the larger driver. In the best case both on axis and off axis responses are flat, the off axis level just going down with increasing off axis angle. In this way we remove the major source of problems: uneven reverberation spectrum. Still the room’s frequency dependent absorption will remain, but its influence will be smaller, as much less sound is radiated towards the room walls.
As said, the directivity depends on wavelength and driver size. It is natural that at same frequency larger drivers are more directional than small. In case of 1238A the directivity control extends to about 300 Hz, where the 60 degrees off axis radiation is 6 dB down from on axis response.

A side effect of limiting the radiation angle with a waveguide is that also the acoustic impedance at the driver diaphragm will change. This improves efficiency; i.e. we get more sound with the same diaphragm displacement. This is naturally true for both MF and HF drivers.

“Woofer, for example: it is a light cone high efficiency/high power handling PA driver actually, which does not go lower than 100 Hz unaided.”

The 1238A woofer really is a high efficiency, high power LF transducer, which has low distortion, sufficient displacement capacity and flat response. High sensitivity is a must for the SPL requirements this product is designed for. Any sensitivity dB gained in the transducer motor design will improve reliability and reduce thermal load due to amplifier power. If you want to get 120 dB SPL output there is a big difference in the needed power depending on the driver sensitivity. If the sensitivity is 80 dB/W we need 10 kW, if 90 dB/W we need 1 kW, if 100 dB/W we only need 100W.
Designing the LF section – box and driver – is relatively straightforward process, where box volume, cutoff frequency and efficiency are interrelated. With active speakers the optimization is simple and in our case we usually trade between amplifier power and box volume.
The beauty of this approach is that because the initial driver sensitivity is good, and because of low QT , its natural response in the box of this size is close to the inverse of room-induced boost. To get neutral response in the room, in most cases LF response has to be reduced – for example flush mounting inherently adds 6 dB to LF, and progressively more because of room loading– and hence the amplifier power needed to straighten the LF response is actually small. There is nothing strange in boosting or cutting responses – EQ if you wish - of minimum phase systems; crossover filter is a good example of this. From system standpoint the multi-way speaker LF, MF and HF sections are band-pass filters combined from acoustical and electrical components. The driver initial responses practically never match with the desired crossover frequencies - were these at the lower or upper end of the driver’s intended passband – and hence response corrections are necessary. Corrections are done in both passive and active designs., The difference being that with active designs we have the possibility to both boost and cut, while passive filters only allow various amounts and slopes of cut. In active systems this possibility covers also woofer: we have freedom to both boost and cut the electrical response to get the desired acoustical response in the listening room.

“…to achieve the good on paper specks.”

We are most interested in how the speaker performs, i.e. sounds. This includes lots of listening tests as well. However, there is lot of research evidence of what makes the speaker sound good and how this correlates with measured performance, i.e. specs. I warmly recommend Floyd Toole’s book “Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms”, it is an excellent representation of this subject.

“…but how it fits the design ideals, in this case "engineering" view of the design process.”

Engineering approach is widely accepted in most tangible areas of life, design of bridges, roads, cars, airplanes, factories, anything. Would you prefer to drive on a bridge designed on feelings? What is the problem with engineering approach to speakers? We think it is best to combine engineering with music and psychoacoustic knowledge.

I hope this clarifies some of the questions.

Ilpo Martikainen
Founder of Genelec
flatfish, modified 6 Years ago.

Re: Huge amount of EQ behind Genelec speakers?

Youngling Posts: 8 Join Date: 9/24/14 Recent Posts
Thank you for asking this kind of questions, which obviously trouble many readers and listeners. I try to answer.

“Speaker is designed against classical hi-fi speaker design rules.”

I may not be aware what these rules may be, but the 1238A is designed as a professional monitoring speaker, where requirements are more stringent than in most hi-fi speakers. For example, monitoring speaker shall be extremely neutral, linear, reliable, serviceable, manufactured with very tight tolerances between units and batches over the years. Any speaker of same model may be paired with any other sample, even made years apart. As the “sound” of the recording is adjusted by listening it with the monitoring speaker, the monitoring speaker must be most revealing. Actually the monitoring speaker has to be more revealing than anything else in the reproduction chain after that. This ensures that end users will not find any surprises.

“Drivers are not chosen because they are the "best"...”

This is difficult to understand. Just the contrary is true: the drivers are carefully selected to be best for the job. If good enough driver is not available, or cannot be tailored from some existing driver, it will be designed from scratch.

“Midrange is an in-house 5" cone, which can not really handle much power…”
The midrange driver is designed and manufactured in house since 1988, as there was simply not good enough midrange drivers available. Its performance and design processes were reported in AES preprint 2755, including sensitivity, distortion, power handling and compression with high levels. The claim that midrange could not handle much power is wrong. The driver was tested up to 1 kW power to make sure it is mechanically stable and reliable. The reliability track record of this driver is extremely good. It was first used in the largest monitor 1035A and since then it is used in all 3-way models down to 1037B.

“…but survives with the efficiency boosting waveguide.”
“Also radiation angles etc are exemplary, which in many other designs by other respected brands are not taken care of at all.”

Genelec created first waveguides in 1983 in the first prototypes of 1022A to control directivity and reduce cabinet edge diffraction. Since then the DCW, as we call it, has been an essential part of our designs. The role of the DCW is to match the directivity of drivers so that both on axis and off axis responses are uniform. This relates mainly to two issues: imaging is improved, as there is less diffraction from cabinet edges, and total perceived response is improved, as the room reverberant field spectrum is much closer to direct sound spectrum. To understand this we have to remember that the human perception is formed from both direct sound and reverberation. In most rooms the reverberation is more important to the perceived balance than direct sound. I take an example: a traditional two-way box system with 200 mm woofer and 25 mm tweeter and crossover at 2,5 kHz. On axis response is tailored flat with decent crossover design. If we measure this off axis, we will find that the woofer response will be falling, progressively more with off axis angle, towards 2,5 kHz, but tweeter response will stay at its on axis level right above the crossover, and starts to fall gradually around 8…10 kHz. This simply relates to the driver directivity; i.e. its radiation size related to wavelength. Converted to the total acoustic power radiated to all directions, this pattern means there will be a dip on the upper woofer band, response will go up when we move to tweeter and starts falling again. This, combined with the frequency dependent absorption of our room, will be the reverberation response spectrum we will hear. This has been, and will be, an endless source of discussion about how good or how bad certain speaker will sound.
The role of waveguide is to limit the radiation angle of a smaller driver to match that of the larger driver. In the best case both on axis and off axis responses are flat, the off axis level just going down with increasing off axis angle. In this way we remove the major source of problems: uneven reverberation spectrum. Still the room’s frequency dependent absorption will remain, but its influence will be smaller, as much less sound is radiated towards the room walls.
As said, the directivity depends on wavelength and driver size. It is natural that at same frequency larger drivers are more directional than small. In case of 1238A the directivity control extends to about 300 Hz, where the 60 degrees off axis radiation is 6 dB down from on axis response.

A side effect of limiting the radiation angle with a waveguide is that also the acoustic impedance at the driver diaphragm will change. This improves efficiency; i.e. we get more sound with the same diaphragm displacement. This is naturally true for both MF and HF drivers.

“Woofer, for example: it is a light cone high efficiency/high power handling PA driver actually, which does not go lower than 100 Hz unaided.”

The 1238A woofer really is a high efficiency, high power LF transducer, which has low distortion, sufficient displacement capacity and flat response. High sensitivity is a must for the SPL requirements this product is designed for. Any sensitivity dB gained in the transducer motor design will improve reliability and reduce thermal load due to amplifier power. If you want to get 120 dB SPL output there is a big difference in the needed power depending on the driver sensitivity. If the sensitivity is 80 dB/W we need 10 kW, if 90 dB/W we need 1 kW, if 100 dB/W we only need 100W.
Designing the LF section – box and driver – is relatively straightforward process, where box volume, cutoff frequency and efficiency are interrelated. With active speakers the optimization is simple and in our case we usually trade between amplifier power and box volume.
The beauty of this approach is that because the initial driver sensitivity is good, and because of low QT , its natural response in the box of this size is close to the inverse of room-induced boost. To get neutral response in the room, in most cases LF response has to be reduced – for example flush mounting inherently adds 6 dB to LF, and progressively more because of room loading– and hence the amplifier power needed to straighten the LF response is actually small. There is nothing strange in boosting or cutting responses – EQ if you wish - of minimum phase systems; crossover filter is a good example of this. From system standpoint the multi-way speaker LF, MF and HF sections are band-pass filters combined from acoustical and electrical components. The driver initial responses practically never match with the desired crossover frequencies - were these at the lower or upper end of the driver’s intended passband – and hence response corrections are necessary. Corrections are done in both passive and active designs., The difference being that with active designs we have the possibility to both boost and cut, while passive filters only allow various amounts and slopes of cut. In active systems this possibility covers also woofer: we have freedom to both boost and cut the electrical response to get the desired acoustical response in the listening room.

“…to achieve the good on paper specks.”

We are most interested in how the speaker performs, i.e. sounds. This includes lots of listening tests as well. However, there is lot of research evidence of what makes the speaker sound good and how this correlates with measured performance, i.e. specs. I warmly recommend Floyd Toole’s book “Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms”, it is an excellent representation of this subject.

“…but how it fits the design ideals, in this case "engineering" view of the design process.”

Engineering approach is widely accepted in most tangible areas of life, design of bridges, roads, cars, airplanes, factories, anything. Would you prefer to drive on a bridge designed on feelings? What is the problem with engineering approach to speakers? We think it is best to combine engineering with music and psychoacoustic knowledge.

I hope this clarifies some of the questions.

Ilpo Martikainen
Founder of Genelec


check and mate :lol:

honestly the amount of rubbish posted on gear forums with people who don't know how to mix for ****

it's when you are used to mix on **** monitors you think geneis are flattering.
that's not the case.
they are simply good speakers and you were used to mix on **** :lol:
folan, modified 6 Years ago.

Re: Huge amount of EQ behind Genelec speakers?

Padawan Posts: 54 Join Date: 10/13/14 Recent Posts


Engineering approach is widely accepted in most tangible areas of life, design of bridges, roads, cars, airplanes, factories, anything. Would you prefer to drive on a bridge designed on feelings? What is the problem with engineering approach to speakers? We think it is best to combine engineering with music and psychoacoustic knowledge.

I hope this clarifies some of the questions.

Ilpo Martikainen
Founder of Genelec


Wow! Thank you for answer! Quite a lengthy post!

I understand that from an engineering point of view you can reach different paths to achieve the desired results..... but wouldn't be better for a driver to reach low frequencies unaided rather than forcing with EQ?
ilkka-rissanen, modified 6 Years ago.

Re: Huge amount of EQ behind Genelec speakers?

Yoda Posts: 2564 Join Date: 3/23/09 Recent Posts

Wow! Thank you for answer! Quite a lengthy post!

I understand that from an engineering point of view you can reach different paths to achieve the desired results..... but wouldn't be better for a driver to reach low frequencies unaided rather than forcing with EQ?

Hi,

If you use some simple box simulation program, you will quickly notice that there is no such driver on this planet that will reach flat frequency response down to its LF point in a sensibly sized cabinet like ours. Such driver could be made but then it needs to have very high moving mass which inherently results in poor high frequency (meaning above 100 Hz when considering for example a three way woofer) sensitivity. All passive and active speakers have filtering done in their crossovers to result in flat(ter) LF response.