scotts
Inspired
Proviso:
Jay was nice enough to test one of my QSC K10s for free. He will not be providing a detailed printed report nor will he be providing graphic data. That wasn't our agreement (and I don't need that information anyway).
There are two independent loudspeaker testing facilities in America that I believe Jay had some hand in designing. For about $1500 they will provide extensive test data and complete written evaluation of any speaker you send them.
________________________
To make the QSC K10 behave to the best of its ability two things can be done:
1) Switch the wires to the high frequency driver (see end of post for method).
2) Add corrective PEQ at the end of your patches.
1) Phase issue
The K10, like many speakers, comes from the factory with the HF driver wired out of phase to the LF driver. Sometimes this is done because the designer(s) believe that it will clear up some anomaly in the speakers presentation. Sometimes this is done because the designer(s) believe that whether the drivers are in phase or out of phase makes no audible difference. More often it appears to be done because "that's the way we always do it". According to Jay wiring the drivers out of phase is always a bad idea.
I corrected the phase on my K10 before my gig last night. The effect on my pre-recorded break music (Chet Baker) was noticeable and a distinct improvement. Parts of this particular CD get played at my house gig throughout the year. I know the disc and I know the room. The trumpet and saxophone sounded far more detailed and clear. The difference was noticeable from several different listening positions.
2) Corrective PEQ
My problem with the K10 (and my problem with my Turbosounds) is my perception that they both do funny things to the lower mids. Jays analysis shows that the phenomena I am experiencing is actually being caused in the 700Hz [AND DOWN] range (edited 6/2/11). The K10 can be made to behave to the best of its ability by placing a PEQ last in line in your patch with the following setting:
[BAND 1]
Shelving
700Hz
Q .707
-3dB
I made the phase change and implemented the corrective PEQ and I am know far more satisfied with the K10. The mid issue noticeably lessened and things just sound better. My initial impression is that my adjusted K10 now out performs my Turbosound TCS (but I have not directly tested this).
Another EQ issue:
[COMMENT REMOVED. BAD PRESENTATION OF PARTIALLY GRASPED IDEA CAUSING CONFUSION]
Overall, with the above corrections implemented, the K10 is pretty darn good for its price point. In terms of relative flatness and overall transparency it destroys it nearest price point JBL stuff.
________________________
Flawed design. The issue that can't be compensated...
Worst: LF speaker on a flat surface with HF driver
The K10, like the majority of loudspeakers, is deeply flawed by design. Putting a low frequency speaker on a flat surface with a high frequency driver is the absolute worst of the three possible designs that Jay and I discussed. No amount of design skill, design trickery, DSP, etc. can correct out all the bad acoustical anomalies inherent in this design. It is impossible to build a loudspeaker of this type that will perform transparently across any listening spectrum. Unfortunately this design happens to be the most cost effective way to produce a loudspeaker. The nasty price driven game of various degrees of turd polishing goes on. Yes, some of them sound pretty darn good at various price points but the best of these designs are reasonably far away from transparent reproduction at various listening positions.
Better: LF horn on a flat surface with HF horn
Get rid of the LF speaker and use a LF horn + HF horn and things take a considerable step up. I believe Jay said this was being done in theater sound way back in the day. Why did the industry switch from this demonstrably better design to the now ubiquitous speaker plus horn? A low frequency horn cost more than a low frequency speaker. Also, the cabinet has to be a bit bigger to handle the low frequency horn.
"Golly Dick. These financial numbers are impressive. I believe we'll go with the speaker/horn design. Let the engineers know. I'm sure they can come up with a way to make it sound good enough."
Best: Co-axial
There is no getting around the issue. This is simply the best design currently known. Proper test data bears this out. In the case of a well designed, high end co-axial product, your ears will bear this out. It should be noted that a system can utilize a co-axial speaker and still be poorly designed. The mere presence of a co-axial speaker doesn't insure transparency.
P.S.
I am still badgering Jay to bring a reasonably priced, bi-amped, high end co-axial monitor to the retail market. I have heard high-end, co-axial transparency and it is a beautiful thing.
________________________
Some myth-busting courtesy of Jay...
Myth 1: Speaker Coupling
There is no such thing as "speaker coupling" with the ground.
You know...
"...when I set my speaker on the ground it couples with the surface and the bottom end gets increased...".
Yeah, I know, even people that are supposed to know what they are doing talk about it this way. The perceived phenomena has nothing to do with ground contact and everything to do with speaker proximity to any given surface. After a few people fuss at me over this I'm sure Jay will step in with a more developed explanation.
Myth 2: Wood Cabinet Is Better Than Plastic
I have been told this by every speaker person I have ever met (except Jay). I believed it because all the good sounding cabinets I have owned and/or tested have been made of wood. Well, the K10 has a plastic cabinet and with Jays adjustments I like it better than my wooden Turbosounds.
Apparently the issue isn't that a wood cabinet makes for the best speaker; it's that the best speakers happen to have cabinets made of wood. Plastic cabinets have mostly been used in cheaper, poorly designed, price point targeted products. Jay says that a properly designed plastic cabinet can perform equally as well as its wooden counterpart.
________________________
Changing the K10 HF driver phase:
~remove the four screws securing the front grill
~use a small probe or screwdriver at two corners to draw the grill edges out of the cabinet track / the grill will then lift off
~remove the screws securing the LF speaker
~lift the speaker out by first levering it up from the recessed spots in the cabinet
~mark the LF wires / they need to go back just as they are (the LF speaker is in correct phase)
~unplug the LF speaker and put it aside
~note the position of the white fuzzy stuff / remove the white fuzzy stuff
~you can now see the HF driver and its wires
~unplug the two HF driver wires and switch them (gently wiggle them back and forth and they will come off)
~put the white fuzzy stuff back the way you found it
~plug the LF driver back in the way you found it
~be careful not to turn the LF driver as you reinstall it / the wiring harness allows for one mounting position
~reinstall the LF speaker screws
~snap the grill in place / reinstall the four grill screws
***ask yourself why the hell QSC didn't put the damn thing together in phase to begin with***
Jay was nice enough to test one of my QSC K10s for free. He will not be providing a detailed printed report nor will he be providing graphic data. That wasn't our agreement (and I don't need that information anyway).
There are two independent loudspeaker testing facilities in America that I believe Jay had some hand in designing. For about $1500 they will provide extensive test data and complete written evaluation of any speaker you send them.
________________________
To make the QSC K10 behave to the best of its ability two things can be done:
1) Switch the wires to the high frequency driver (see end of post for method).
2) Add corrective PEQ at the end of your patches.
1) Phase issue
The K10, like many speakers, comes from the factory with the HF driver wired out of phase to the LF driver. Sometimes this is done because the designer(s) believe that it will clear up some anomaly in the speakers presentation. Sometimes this is done because the designer(s) believe that whether the drivers are in phase or out of phase makes no audible difference. More often it appears to be done because "that's the way we always do it". According to Jay wiring the drivers out of phase is always a bad idea.
I corrected the phase on my K10 before my gig last night. The effect on my pre-recorded break music (Chet Baker) was noticeable and a distinct improvement. Parts of this particular CD get played at my house gig throughout the year. I know the disc and I know the room. The trumpet and saxophone sounded far more detailed and clear. The difference was noticeable from several different listening positions.
2) Corrective PEQ
My problem with the K10 (and my problem with my Turbosounds) is my perception that they both do funny things to the lower mids. Jays analysis shows that the phenomena I am experiencing is actually being caused in the 700Hz [AND DOWN] range (edited 6/2/11). The K10 can be made to behave to the best of its ability by placing a PEQ last in line in your patch with the following setting:
[BAND 1]
Shelving
700Hz
Q .707
-3dB
I made the phase change and implemented the corrective PEQ and I am know far more satisfied with the K10. The mid issue noticeably lessened and things just sound better. My initial impression is that my adjusted K10 now out performs my Turbosound TCS (but I have not directly tested this).
Another EQ issue:
[COMMENT REMOVED. BAD PRESENTATION OF PARTIALLY GRASPED IDEA CAUSING CONFUSION]
Overall, with the above corrections implemented, the K10 is pretty darn good for its price point. In terms of relative flatness and overall transparency it destroys it nearest price point JBL stuff.
________________________
Flawed design. The issue that can't be compensated...
Worst: LF speaker on a flat surface with HF driver
The K10, like the majority of loudspeakers, is deeply flawed by design. Putting a low frequency speaker on a flat surface with a high frequency driver is the absolute worst of the three possible designs that Jay and I discussed. No amount of design skill, design trickery, DSP, etc. can correct out all the bad acoustical anomalies inherent in this design. It is impossible to build a loudspeaker of this type that will perform transparently across any listening spectrum. Unfortunately this design happens to be the most cost effective way to produce a loudspeaker. The nasty price driven game of various degrees of turd polishing goes on. Yes, some of them sound pretty darn good at various price points but the best of these designs are reasonably far away from transparent reproduction at various listening positions.
Better: LF horn on a flat surface with HF horn
Get rid of the LF speaker and use a LF horn + HF horn and things take a considerable step up. I believe Jay said this was being done in theater sound way back in the day. Why did the industry switch from this demonstrably better design to the now ubiquitous speaker plus horn? A low frequency horn cost more than a low frequency speaker. Also, the cabinet has to be a bit bigger to handle the low frequency horn.
"Golly Dick. These financial numbers are impressive. I believe we'll go with the speaker/horn design. Let the engineers know. I'm sure they can come up with a way to make it sound good enough."
Best: Co-axial
There is no getting around the issue. This is simply the best design currently known. Proper test data bears this out. In the case of a well designed, high end co-axial product, your ears will bear this out. It should be noted that a system can utilize a co-axial speaker and still be poorly designed. The mere presence of a co-axial speaker doesn't insure transparency.
P.S.
I am still badgering Jay to bring a reasonably priced, bi-amped, high end co-axial monitor to the retail market. I have heard high-end, co-axial transparency and it is a beautiful thing.
________________________
Some myth-busting courtesy of Jay...
Myth 1: Speaker Coupling
There is no such thing as "speaker coupling" with the ground.
You know...
"...when I set my speaker on the ground it couples with the surface and the bottom end gets increased...".
Yeah, I know, even people that are supposed to know what they are doing talk about it this way. The perceived phenomena has nothing to do with ground contact and everything to do with speaker proximity to any given surface. After a few people fuss at me over this I'm sure Jay will step in with a more developed explanation.
Myth 2: Wood Cabinet Is Better Than Plastic
I have been told this by every speaker person I have ever met (except Jay). I believed it because all the good sounding cabinets I have owned and/or tested have been made of wood. Well, the K10 has a plastic cabinet and with Jays adjustments I like it better than my wooden Turbosounds.
Apparently the issue isn't that a wood cabinet makes for the best speaker; it's that the best speakers happen to have cabinets made of wood. Plastic cabinets have mostly been used in cheaper, poorly designed, price point targeted products. Jay says that a properly designed plastic cabinet can perform equally as well as its wooden counterpart.
________________________
Changing the K10 HF driver phase:
~remove the four screws securing the front grill
~use a small probe or screwdriver at two corners to draw the grill edges out of the cabinet track / the grill will then lift off
~remove the screws securing the LF speaker
~lift the speaker out by first levering it up from the recessed spots in the cabinet
~mark the LF wires / they need to go back just as they are (the LF speaker is in correct phase)
~unplug the LF speaker and put it aside
~note the position of the white fuzzy stuff / remove the white fuzzy stuff
~you can now see the HF driver and its wires
~unplug the two HF driver wires and switch them (gently wiggle them back and forth and they will come off)
~put the white fuzzy stuff back the way you found it
~plug the LF driver back in the way you found it
~be careful not to turn the LF driver as you reinstall it / the wiring harness allows for one mounting position
~reinstall the LF speaker screws
~snap the grill in place / reinstall the four grill screws
***ask yourself why the hell QSC didn't put the damn thing together in phase to begin with***
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