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Post by p4t on Feb 26, 2022 23:08:47 GMT -5
How significant the sound difference between stacked and not? I just realized that these already discontinued for dxd 12012 and dxd 808. Because I also interested to try this KK subwoofer. I can get 4 dxd 808 used one. What do you think? The DXD12012 is much more powerful than the 808. the 12012 has two 12' drivers vs the 808's two 8" drivers. However, they do work in the same manner. it depends on the size of your room and how low you require the subwoofer to play. Stacking creates a 6db boost so it does have has significant impact. However, it is possible to achieve a somewhat similar co-location effect depending on your room so stacking is not critical. If you had four 808 and created two stacks of two or one stack of four they could be pretty serious. What main speakers would you be using them with? Yes, dxd 12012 for sure more powerful than dxd 808. I heard this dxd series have fast midbass. I just wondering if I can combined this with 4 JL E112. The guy (he is actually KK dealer in singapore, and has been carrying this product since in the beginning Ken Kreisel start his own company) suggest to set E112 at 60Hz roll of 12 db slope and 808 60Hz high pass. If I place each 808 in the corner, do I will experience similar sound as stacking it? Basically, My target is what is the best way to combined these 808s with E112s. By the way, I am using Martin Logan ESL as main speakers. |
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Post by p4t on Feb 26, 2022 23:14:11 GMT -5
Hi Marcl. What I mean is, I am very curious how the sound character of of this sub, because the way this subs design for stacking. Especially the sound character when 4 of these subs stacked. Yes I think the idea is interesting for two reasons .... the idea of a nearly line source because you could stack four or five in an 8ft ceiling; and that the 808 is 8" drivers which should have less inertia than 12" or larger drivers. Quite a lot of money for four 808's and you'd want two stacks, right? And the Harman principles still apply ... you'd put the stacks front and rear, not left and right (I know, I said it, but nobody would do that  ) To the idea of a stack of smaller drivers .... a couple years ago I heard a demo of a concept that Magnepan has been working on, the "30.7 for condos". The 30.7 has huge planar woofers, but this concept used open baffle woofer modules that were about 3ft tall and triangular (apex toward the front and open back) with four 7" drivers on each face, a 1000W amp, and DSP to smooth it out. Paired with a 4x1ft Magnepan midrange with ribbon tweeter, this 3ft tall module sounded as good or better than the $30,000 6 1/2x4ft 30.7. So in an acoustically small room (where we all live) I could see a stacked solution with smaller drivers, and maybe even better ... open baffle design. The key with stacking those 808's would be getting the DSP right as - from what I could find on the subject from sound reinforcement - there's a specific way phase has to be handled at each level off the floor. + ttocs Actually I want 8 of these 808. But, the stocked is only 4. I bought it used for around 700 US dollar each. I have to imported from Singapore as there are no KK dealer in my country. |
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Post by leonski on Feb 27, 2022 0:04:23 GMT -5
Got It!
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Post by fbczar on Feb 27, 2022 12:03:31 GMT -5
The DXD12012 is much more powerful than the 808. the 12012 has two 12' drivers vs the 808's two 8" drivers. However, they do work in the same manner. it depends on the size of your room and how low you require the subwoofer to play. Stacking creates a 6db boost so it does have has significant impact. However, it is possible to achieve a somewhat similar co-location effect depending on your room so stacking is not critical. If you had four 808 and created two stacks of two or one stack of four they could be pretty serious. What main speakers would you be using them with? Yes, dxd 12012 for sure more powerful than dxd 808. I heard this dxd series have fast midbass. I just wondering if I can combined this with 4 JL E112. The guy (he is actually KK dealer in singapore, and has been carrying this product since in the beginning Ken Kreisel start his own company) suggest to set E112 at 60Hz roll of 12 db slope and 808 60Hz high pass. If I place each 808 in the corner, do I will experience similar sound as stacking it? Basically, My target is what is the best way to combined these 808s with E112s. By the way, I am using Martin Logan ESL as main speakers. I think you should consider two stacks of two 808’s, but a stack of four would be much different from an output and coverage standpoint due to true co-location and the height of the stack. Of course, your room will have something to say about what works best. There is also the concern of localization with all the subs in one place, but the stack does seem to mitigate that issue. The DXD808’s and the DXD12012’s are both extremely quick and wonderful for music. I seriously doubt any sealed sub could work better with a planar or electrostatic speaker. Open baffle subs work well, but they do not have the extreme low end capability of a sub like the Kreisel’s. The good news for you is with four subs you have extraordinary flexibility and can experiment to your hearts delight. I do not think you can go wrong. By the way, I would set the initial levels of your main speakers at 79db and your subs at 85db and work from there. Also don’t be afraid of experimenting with higher crossover points. The Kreisel’s handle higher frequencies well. |
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Post by ttocs on Feb 27, 2022 12:32:45 GMT -5
I've done this comparison before, but since I was in need of a current comparison for some tests I'm getting ready for I figured I'd post the results. This is a REW plot showing the difference between two UMIK-1 mics and the EMM-1 mic from Emotiva. The frequency range used here is 15-1000Hz. The three mics are held together in a microphone spider so the key thing to keep in mind is that the mic elements are about 3/4" from each other, so higher frequencies are expected to wander. For my purposes right now I'm only interested in the lowest frequencies, under 300Hz. Up to 650Hz the three mics are indistinguishable from each other. I don't worry about 1dB, ever, due to the fact that with each sweep there can be differences, so I'm willing to forgive a dB or so tolerance.  But, above about 3kHz the EMM-1 mic starts diving down and kinda levels off at 7kHz, down about -7dB at this point from the UMIKs. This is a steep downhill trend. I reoriented the mics and even moved the boom 1" in both directions, but the trend is pretty close to this plot, except to say that the average is actually closer to -6dB from the average of the UMIK mics. Psychoacoustic Smoothing is used here to make it easier to see.  Here's what the test rig looks like.  Also, there are no room treatments at the moment. Just got finished with some remodeling and will be adding them back soon now that cleanup is done. I'll be making new bass traps. The tests I'm gearing up for are to test stacking up to six subwoofers to see what happens. |
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Post by marcl on Feb 27, 2022 12:47:41 GMT -5
Okay so here's a puzzle: Given: LFE goes only to the center sub output and bass management goes to large L+R. If: I manage to invert the polarity of only the LFE (through a process of which I will spare you the details), And If: the frequency response measurements of all channels including LFE are identical both ways, ... Will I hear a difference? Evidence ... frequency response plot of LCR and LFE before and after LFE polarity reversal ... traces superimpose exactly.  Phase and Impulse response plots showing LCR identical; LFE 180 degrees out of phase in phase plot, and inverted in impulse plot.   |
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Post by fbczar on Feb 27, 2022 12:56:39 GMT -5
Lots of info at the Kreisel site, not all of which I agree with. No mention made of ISOBARIC which is the starting point for these kinds of designs...... This particular design is not ISOBARIC. Both drivers push outward together, and pull inward together. The internal air volume is not a constant pressure or volume. The drivers are inverted from each other relative to the box, but the phase is also inverted relative to each other. So one is in a forward motion, and the other is in reverse, hence, why both move out together and in together. If you look at the animation you can see the action of both drivers (you may need to click it to see the animation). <button disabled="" class="c-attachment-insert--linked o-btn--sm">Attachment Deleted</button> And when you stack them they are inverted and clamped together. They also have THX settings marked so both, or all, subs in a stack have optimal settings. I failed to mention the subs, when stacked, side fire in different directs and the bottom sub also fires down at the floor while the top sub fires up. This is said to allow the stack to couple to the room more efficiently. |
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Post by leonski on Feb 27, 2022 14:58:33 GMT -5
About standardized mics? (I'm careful not to call them calibrated)
IF the software knows the curve, it shouldn't make any difference. If the mic is -6db for a range of frequencies? Software knows and 'adds' the corrrection back to whatever output is required to adjust.....
Are ANY of these mics NIST traceable? And if so? How often to you send them BACK to be recertified? And at what cost? Do you get a new curve when doing the recent?
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Post by donh50 on Feb 27, 2022 19:06:33 GMT -5
You can buy NIST-certified measurement mics. Pretty sure I have the one for mine, someplace... It cost about $1200 back when I first got it. Now, I have a $100 CSL-calibrated UMIK-1. CSL equipment is traceable to NIST via third-party cal (same thing we do for our million-dollar test equipment). The good, or bad depending on how you look at it, news is that, while the UMIK-1 does not have the noise floor or dynamic range of the Earthworks mic, the frequency response using the cal file is basically identically to my measurement mic from 5 Hz to >20 kHz (don't remember the top end of the UMIK-1). It is somewhat bittersweet that a $100 mic and free REW SW does everything and more that my previous $10k+ measurement rig does, with far less hassle. CSL UMIK-1 link: cross-spectrum.com/measurement/calibrated_umik.html |
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Post by ttocs on Feb 27, 2022 22:00:54 GMT -5
Are ANY of these mics NIST traceable? And if so? How often to you send them BACK to be recertified? And at what cost? Do you get a new curve when doing the recent? I don't go nuts with this stuff. For me, after using a particular mic for a period of time I get to know what it does vs how the system sounds. So in the end, for me, it's all relative. I cannot imagine needing to be any more accurate in a multipurpose great room with furniture that moves around as needed for the amount of guests on one night vs another. If I were that concerned about a mic being calibrated and certified, I would only invite the same number of people over and have them wear the same clothes and sit in the same seats every time I played a movie, otherwise, the sound would not be the same. |
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Post by ttocs on Feb 27, 2022 22:51:12 GMT -5
Getting ready to test a stack of up to six subs. I'll use three mics and spread them across the main seating area to measure how each additional subwoofer might change the response at each mic location. Each "measurement" of each new combination of subs will actually be three sweeps because only one mic can be used at a time. Probably the best location to use would be the middle of the front wall, so that'll be the starting location. Orientation however, will probably be something to play with. Should all subs be arranged with drivers facing the same way? or, maybe alternate with the bottom facing one direction, the next up facing reverse, etc? The iterations increase as other considerations are mixed in, like phase for example. Room layout showing mic locations.  |
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Post by leonski on Feb 28, 2022 0:09:46 GMT -5
Keep in mind that the 'calibration lab' is NOT accredited by any of the 3 major players.......
Also? I wonder if connecting to different computers effects the results? I'm just curious here
When I did metrology for a living? I sent MY stuff off annually for a recert. I had silicon wafers with different films I used to check in-house gear for accuracy AT THAT POINT
Other standards were generated In-House and included reflectance and resistivity.....All metrology tools were checked 2x or 3x daily and results put into a control chart.
I suspect if I did something Akin to a gauge R+R study, using 3 different operators and 10 measurement points? I'd get data which MAY not line up, let alone yield the same result to OUTPUT.
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Post by p4t on Feb 28, 2022 1:33:32 GMT -5
Getting ready to test a stack of up to six subs. I'll use three mics and spread them across the main seating area to measure how each additional subwoofer might change the response at each mic location. Each "measurement" of each new combination of subs will actually be three sweeps because only one mic can be used at a time. Probably the best location to use would be the middle of the front wall, so that'll be the starting location. Orientation however, will probably be something to play with. Should all subs be arranged with drivers facing the same way? or, maybe alternate with the bottom facing one direction, the next up facing reverse, etc? The iterations increase as other considerations are mixed in, like phase for example. Room layout showing mic locations. <button disabled="" class="c-attachment-insert--linked o-btn--sm">Attachment Deleted</button> Just wondering for standard front facing sub can be stacked but facing opposite direction for each sub to reduce vibration, and how it will affect the sound compare to all facing the same directions. |
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Post by marcl on Feb 28, 2022 8:40:29 GMT -5
Getting ready to test a stack of up to six subs. I'll use three mics and spread them across the main seating area to measure how each additional subwoofer might change the response at each mic location. Each "measurement" of each new combination of subs will actually be three sweeps because only one mic can be used at a time. Probably the best location to use would be the middle of the front wall, so that'll be the starting location. Orientation however, will probably be something to play with. Should all subs be arranged with drivers facing the same way? or, maybe alternate with the bottom facing one direction, the next up facing reverse, etc? The iterations increase as other considerations are mixed in, like phase for example. Room layout showing mic locations. <button disabled="" class="c-attachment-insert--linked o-btn--sm">Attachment Deleted</button> I know I've mentioned this before .... but at subwoofer wavelengths, the subs are omnidirectional, right? I can see alternating for vibration balance, but otherwise it shouldn't matter. And yes, middle of the front wall to start. I wonder if this might be useful ... especially P.6 Delays. electrovoice.com/media/downloads/wp_subwoofer_arrays_v04.pdf |
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Post by ttocs on Feb 28, 2022 9:00:52 GMT -5
Getting ready to test a stack of up to six subs. I'll use three mics and spread them across the main seating area to measure how each additional subwoofer might change the response at each mic location. Each "measurement" of each new combination of subs will actually be three sweeps because only one mic can be used at a time. Probably the best location to use would be the middle of the front wall, so that'll be the starting location. Orientation however, will probably be something to play with. Should all subs be arranged with drivers facing the same way? or, maybe alternate with the bottom facing one direction, the next up facing reverse, etc? The iterations increase as other considerations are mixed in, like phase for example. Room layout showing mic locations. <button disabled="" class="c-attachment-insert--linked o-btn--sm">Attachment Deleted</button> Just wondering for standard front facing sub can be stacked but facing opposite direction for each sub to reduce vibration, and how it will affect the sound compare to all facing the same directions. Some possibilities of orientation are: All facing same way, same phase: Movement in unison. All facing same way, alternating inverted phase: Movement in opposition. Alternating facing, alternating inverted phase: Movement in unison. Alternating facing, same phase: Movement in opposition. Same four possibilities as above, driver motion oriented perpendicular to wall. Same four possibilities as above, driver motion oriented parallel to wall. All variations of above with n number of subs involved, 2, 3, 4, 5, 6. Rel faces their triple stacks in the same orientation, facing towards the MLP. Do they invert the phase of the middle sub? I only know they say to adjust the gain and crossover settings of each sub in the stack, but there are no instructions I've been able to find from Rel as to how these settings should be adjusted. My double stacked sub settings also include phase, and a couple special contour settings so each sub has unique settings, not same as other. The important thing to keep in mind with my setup is that the primary goal of my subwoofers is to assist my main speakers without DSP control between each main speaker and it's pair of subwoofers which are only connected using speaker wire and their speaker level connections. It's unknown at the moment if this connection method can be maintained for both main speakers if the sub tower is no longer as close to each speaker as currently configured. This might be one reason, in addition to others, that Rel only goes to three subs in their stereo stacks, so each stack is almost touching the main speaker. So, this experiment may only provide info for subwoofer performance in general, and not for my specific usage. I use a thin rubber mat (actually, it's tool drawer liner from a home store, and over time the subs become "stuck" together so there is no movement between them) between my stacked subs. My subs have removable feet, so only the bottom sub has feet installed. |
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Post by ttocs on Feb 28, 2022 9:30:40 GMT -5
I know I've mentioned this before .... but at subwoofer wavelengths, the subs are omnidirectional, right? I can see alternating for vibration balance, but otherwise it shouldn't matter. And yes, middle of the front wall to start. I wonder if this might be useful ... especially P.6 Delays. electrovoice.com/media/downloads/wp_subwoofer_arrays_v04.pdfYes, at low freq the wavelengths are almost omnidirectional, but can be made to be less omnidirectional with layout and setup. In-room is a whole 'nuther ballgame though, as has been pointed out in this thread. With that said, the principles involved can be used to aid some problems, like SBIR for example. I placed bass traps with SBIR in mind, and it's the only way I could use a minimum amount of trapping with good effect, but they are definitely part of the room decor being almost in the middle of the space. The new traps will not be as tall, but I'm making more of them to possibly use in other locations. For whatever reason, in my room when I used lots of thick bales of absorption along the floor/wall boundaries, and/or in corners, etc, it just didn't work as well. It's probably due to the all-glass-window wall to the right and behind the right front speaker. How things are currently positioned, except those bass traps aren't in place right now, but it's where they were before the remodeling started.  I read that ElectroVoice info a couple years ago, and yes, it's very helpful info! The graphics are great in how they show the propagation/cancellation of different frequencies with various layouts. Great stuff! |
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Post by marcl on Feb 28, 2022 9:30:54 GMT -5
Just wondering for standard front facing sub can be stacked but facing opposite direction for each sub to reduce vibration, and how it will affect the sound compare to all facing the same directions. Some possibilities of orientation are: All facing same way, same phase: Movement in unison. All facing same way, alternating inverted phase: Movement in opposition. Alternating facing, alternating inverted phase: Movement in unison. Alternating facing, same phase: Movement in opposition. Same four possibilities as above, driver motion oriented perpendicular to wall. Same four possibilities as above, driver motion oriented parallel to wall. All variations of above with n number of subs involved, 2, 3, 4, 5, 6. Rel faces their triple stacks in the same orientation, facing towards the MLP. Do they invert the phase of the middle sub? I only know they say to adjust the gain and crossover settings of each sub in the stack, but there are no instructions I've been able to find from Rel as to how these settings should be adjusted. My double stacked sub settings also include phase, and a couple special contour settings so each sub has unique settings, not same as other. The important thing to keep in mind with my setup is that the primary goal of my subwoofers is to assist my main speakers without DSP control between each main speaker and it's pair of subwoofers which are only connected using speaker wire and their speaker level connections. It's unknown at the moment if this connection method can be maintained for both main speakers if the sub tower is no longer as close to each speaker as currently configured. This might be one reason, in addition to others, that Rel only goes to three subs in their stereo stacks, so each stack is almost touching the main speaker. So, this experiment may only provide info for subwoofer performance in general, and not for my specific usage. I use a thin rubber mat (actually, it's tool drawer liner from a home store, and over time the subs become "stuck" together so there is no movement between them) between my stacked subs. My subs have removable feet, so only the bottom sub has feet installed. Seems like the Alignment Tool method would be the easiest way to do this. Stack them all facing forward, then starting from the bottom align two, then the next, then the next. If it's beneficial to invert phase you can see that in the tool simulation. |
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Post by p4t on Feb 28, 2022 10:33:18 GMT -5
Some possibilities of orientation are: All facing same way, same phase: Movement in unison. All facing same way, alternating inverted phase: Movement in opposition. Alternating facing, alternating inverted phase: Movement in unison. Alternating facing, same phase: Movement in opposition. Same four possibilities as above, driver motion oriented perpendicular to wall. Same four possibilities as above, driver motion oriented parallel to wall. All variations of above with n number of subs involved, 2, 3, 4, 5, 6. Rel faces their triple stacks in the same orientation, facing towards the MLP. Do they invert the phase of the middle sub? I only know they say to adjust the gain and crossover settings of each sub in the stack, but there are no instructions I've been able to find from Rel as to how these settings should be adjusted. My double stacked sub settings also include phase, and a couple special contour settings so each sub has unique settings, not same as other. The important thing to keep in mind with my setup is that the primary goal of my subwoofers is to assist my main speakers without DSP control between each main speaker and it's pair of subwoofers which are only connected using speaker wire and their speaker level connections. It's unknown at the moment if this connection method can be maintained for both main speakers if the sub tower is no longer as close to each speaker as currently configured. This might be one reason, in addition to others, that Rel only goes to three subs in their stereo stacks, so each stack is almost touching the main speaker. So, this experiment may only provide info for subwoofer performance in general, and not for my specific usage. I use a thin rubber mat (actually, it's tool drawer liner from a home store, and over time the subs become "stuck" together so there is no movement between them) between my stacked subs. My subs have removable feet, so only the bottom sub has feet installed. Seems like the Alignment Tool method would be the easiest way to do this. Stack them all facing forward, then starting from the bottom align two, then the next, then the next. If it's beneficial to invert phase you can see that in the tool simulation. Setting for KK sub, each sub must have all the same setting and no time delay. One of the main reason is to eliminate any vibration. But I do not know for regular front facing sealed sub, should use any time delay or not for each sub. |
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Post by ttocs on Feb 28, 2022 10:39:59 GMT -5
Seems like the Alignment Tool method would be the easiest way to do this. Stack them all facing forward, then starting from the bottom align two, then the next, then the next. If it's beneficial to invert phase you can see that in the tool simulation. Setting for KK sub, each sub must have all the same setting and no time delay. One of the main reason is to eliminate any vibration. But I do not know for regular front facing sealed sub, should use any time delay or not for each sub. I read about this on the Kreisel site. They do say to set all identical, but this is due to expecting correction to be done for the sub-array. This may hold true for this experiment as well, but it would be great if it would work as my setup currently does, without the need for extra DSP or correction, in other words, totally self-contained as a stand-alone setup so I could keep using the subs like I currently do when using Reference Stereo for music. |
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Post by fbczar on Feb 28, 2022 14:40:12 GMT -5
Setting for KK sub, each sub must have all the same setting and no time delay. One of the main reason is to eliminate any vibration. But I do not know for regular front facing sealed sub, should use any time delay or not for each sub. I read about this on the Kreisel site. They do say to set all identical, but this is due to expecting correction to be done for the sub-array. This may hold true for this experiment as well, but it would be great if it would work as my setup currently does, without the need for extra DSP or correction, in other words, totally self-contained as a stand-alone setup so I could keep using the subs like I currently do when using Reference Stereo for music. Kreisel told me to EQ a stack as if it were one sub. Check the photos of the stack of four and note the subs do not face in the same direction and do not fire in the same direction. They are designed to function as one unit. It is tempting to think it possible to optimize for each sub, but you would need four independent subwoofer outs to do so and even if you did the outputs would need to be 100% identical. All in all it is better to just treat each stack as one sub. |
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