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Test of the Top of the Line M&K DXD 12012 Sub up at Sound&Vision magazine - Page 2

post #31 of 81
Quote:
Originally Posted by audiofan1 View Post

Even when I try to ask questions to those who are the knowledgeable here it seems If one doesn't agree 100% with the answers , its the block list ?
Dude they keep stating facts to you. Facts are not agreeable or disagreeable they are facts. You simply just disregard this information as if it were an opinion. I know you are not purposely trying to be disruptive but your continuous posts show that you clearly do not understand the basic knowledge one needs to debate this subwoofer with science and facts.
The sooner the Light Bulb goes off over your head the better the discussion can be had about this subwoofer.
I am just glad that you are having this debate in the proper thread and I also give you credit for remaining positive with your posts and not letting it turn negative.
Enjoy
Chris
Edited by countryWV - 8/17/13 at 6:40am
post #32 of 81
Quote:
Originally Posted by audiofan1 View Post

I completely agree all subs are omnidirectional,what I was referring to here was the dispersion pattern of the KK vs. other designs be it forward firing, down, or something like the Sub 2, the New Triax and if not mistaken the Seaton has opposing drivers as well.
Omni-directional is just that, expanding in all directions equally. No matter how many drivers or ports you have or which way they face the output pattern in the subwoofer bandwidth will be the same.
Quote:
Am I to assume you mean they will all couple to the corner the same as the KK when corner loaded ?
They will. This is why:
http://www.trueaudio.com/st_spcs1.htm
The only exception to spatial loading rules is when the enclosure is large enough that the output is directional, and the output wave cannot wrap around the speaker to then reflect off boundaries behind the speaker. With subs small enough to fit in a home that does not occur.
post #33 of 81
"So who's the DXD-12012 for? Three groups: audio pros, serious audiophiles, and very hardcore and well-heeled home theater fanatics. In other words, people who are very, very picky about sound."


This statement is the Justification of ownership statement. The review clearly shows this subwoofer to be nothing special but this statement allows the owners to believe They are Special.rolleyes.gif
There is a fourth group for whom this subwoofer is intended: The Gullible Ones.
I am not trying to put this group down b/c My favorite group of women have always been the gullible ones.biggrin.gif
I have to congratulate S & V for another unrealistic and confusing review. Kreisler sure got his $$$ worth with this one.rolleyes.gif
Chris
Edited by countryWV - 8/17/13 at 9:25am
post #34 of 81
Quote:
Originally Posted by countryWV View Post

"So who's the DXD-12012 for? Three groups: audio pros, serious audiophiles, and very hardcore and well-heeled home theater fanatics. In other words, people who are very, very picky about sound."

This statement is the Justification of ownership statement. The review clearly shows this subwoofer to be nothing special but this statement allows the owners to believe They are Special.rolleyes.gif
There is a forth group for whom this subwoofer is intended: The Gullible Ones.
I am not trying to put this group down b/c My favorite group of women have always been the gullible ones.biggrin.gif
I have to congratulate S & V for another unrealistic and confusing review. Kreisler sure got his $$$ worth with this one.rolleyes.gif
Chris

The review definitely ends on a political note to say the least, but fortunately its easy enough to read between the lines as they spell it out clearly. The only interesting thing about this sub is what they are trying to get for it in light of what you get in return and what you could have bought instead. Anyone paying anywhere close to 3k for this unit has flat out been ripped off and has been taken hook, line and sinker by the extremely bloated marketing for this unit. Nobody in their right mind who has done their homework would buy this severely overpriced sub. Not saying it's a bad sub, it's just WAY overpriced and as this review even mentions, much more can be had for much less.
Edited by Toe - 8/17/13 at 7:12am
post #35 of 81
Bosso's post has a link explaining how different subwoofer designs boundary influences react in a corner placement. However even the dual opposed tested that stayed the same with rotation, is still ~+/-15 dB. Many of us have measured our systems, and the gear to do so is a small fraction of the price of one of these subwoofers. I recommend anyone on this forum not measuring, run, don't walk, to get this ability. Bosso has also shown in the past how stacking subwoofers can smooth a response.

Like Bosso states KK is no dummy. I havent seen any in this thread say its a bad design or doesn't sound good. Its the output for the $. For reference level full spectrum playback multiples will be needed. Bosso uses 4 of his up/down firing dual 15" bringing the total to eight 15" drivers to get him in his room to it.

So heck get a quad drive, maybe it will take an octo. But if you could get flat, broadband, uncompressed reference level playback with a single, why does Ken sell multiple packages?
post #36 of 81
Days of our subwoofers....
post #37 of 81
Quote:
Originally Posted by basshead81 View Post

Days of our subwoofers....

yuh think smile.gif
post #38 of 81
Quote:
Originally Posted by wth718 View Post


I'm using 2 Stereo Integrity 18s. The raw, un-eq'd, ground plane, long-term response looks like the finished 12012. Throw in an amp with flat response down to 5 Hz feeding duals, no limiters (as yours DOES employ), with an applied LT, and room gain, and this is what you get:.

To correct you on one point; all amplifiers employ limiters. Hard, soft, progressive, clip, voltage peak, etc., needs to be qualified, but all of them have blocking caps and limiters.

Quote:
Originally Posted by Luke Kamp View Post

Bosso's post has a link explaining how different subwoofer designs boundary influences react in a corner placement. However even the dual opposed tested that stayed the same with rotation, is still ~+/-15 dB. Many of us have measured our systems, and the gear to do so is a small fraction of the price of one of these subwoofers. I recommend anyone on this forum not measuring, run, don't walk, to get this ability. Bosso has also shown in the past how stacking subwoofers can smooth a response.

My point was aimed at Fitz's claim that all subwoofers benefit equally from corner loading. Josh clearly proves that is not true with a single, simple exercise. The FF sub shows 12dB swings placed in the same corner. I would call that significant. My own tests (all in-room and far more comprehensive than the one I cited from Josh) show similar results. Again, the point being that all subwoofers do NOT benefit equally from corner placement.

Quote:
Originally Posted by Luke Kamp View Post

Like Bosso states KK is no dummy. I havent seen any in this thread say its a bad design or doesn't sound good. Its the output for the $. For reference level full spectrum playback multiples will be needed. Bosso uses 4 of his up/down firing dual 15" bringing the total to eight 15" drivers to get him in his room to it.

So heck get a quad drive, maybe it will take an octo. But if you could get flat, broadband, uncompressed reference level playback with a single, why does Ken sell multiple packages?

I think the confusion here is the whole "My sub handled WOTW at reference level with no problems" thing. In AF's defense, this is not a new problem. Folks have been claiming that since the movie was released on DVD a decade ago.

Heck, Josh made similar positive subjective comments in the discussion of his review of the P'digm Sub 2 regarding its heavy use of limiters and no one broke his balls like they are here with AF. wink.gif

I know of no subwoofer system on this planet that "handles" WOTW with no problems in the defined sense of full BW playback with no distortions (save a +/-3dB FR non-linearity). Some will claim the TRW can, but that will have to be shown to me with the appropriate data.

The key word here is "handle". Sub owners really mean that their subs didn't explode or make bad noises or catch fire. They generally have no earthly idea what playback of WOTW at reference level means, and that includes the double-octo 18" build with multi-5 figure watts systems.

One reason I know this to be true is that in all of the thousands of references to scenes in WOTW, the most difficult scene in the movie to reproduce "with no problems" is never mentioned at all. That simply tells me that all of the subs that had "no problem" with WOTW at 0dBRL simply did not even approach playback of that scene in flat full BW with no distortions.



As you can see, although my system "handled" this scene, it did so 'only' down to around 4 Hz, but still left 2 octaves on the table. eek.gif

It wouldn't matter if I had 60 15s and any # of watts, the signal simply is not getting to the drivers for them to react to.

I have to admit that I'm partial to anyone who has the sense to know that stacking, specific driver config, no HPF, sealed systems are a necessary part of the formulae for successful design. But, that's where it ends for me in this case. I'm a decade ahead of KK in this arena and I really need to see more specifics regarding the "Transflux Photon Injector Warp Drive Eco-Flush Driver Loading", or whatever the he!! it's called before I'd offer any actual specific opinions.

Just quickly looking at the review FR graph and assuming it's accurate (which I do not), the sub would not yield a flat response to 10 Hz in my room without some post-PEQ doctoring:

(KK in black, Raptor in green)



KK claims low 500s CM^2 Sd (a pair would have more surface area than a UXL-18), but doesn't mention throw (to calc displacement), so how many might be needed is a missing variable, but $/dB is a tough one to nail down. It can be free and matter not if it can't reach the bottom octaves for any # of reasons (sig chain roll off, not enough power, etc.).
post #39 of 81
I have done the tests with rotating subs in my room and two others with single front facing raditor driver and have seen the effects first hand and agree.

It baffles me just how many throw a sub in a corner, turn it up to reference and even beyond and conclude they are getting all there is on a disk. Its a fact that driver excursion doubles for a 6 dB increase so its a fairly simple test examining excursion on a 5 star scene, to judge sub system limits. Doing the right way involves set of measurements, maxmercy (data-bass bass film thread) has a great thread around documenting his tests. Once knowing limits with and using peak/ average graphs such as the ones he supplies, you can have a darn good set of data of how your system can handle each film.

I have the utmost respect for you and Bill as well as others and tend to stalk those in the know, at least their posts on the forums. I have learned a lot, but no doubt have a long way to go. Afaik you have more real world experience and knowledge on the low end in room as anyone on the forum, or at least who freely posts on the subject. I might add a big thank you for the lessons. I really enjoyed the discussion on wave summation of the ulf in carp's build thread.

Speaking of carp, i am guessing without looking the scene you speak of is the plane crash or lightining. I liked the plane crash more at his place than the emergence scene and have become a big fan of the lower the better. At a turtles pace i am working on a quad si 18 system myself for my humble small basement concrete theater. I am very interested in the details and availability of your seqss signal shaper. Shoot me a pm if the availability answer is yes.cool.gif
Edited by Luke Kamp - 8/17/13 at 11:02am
post #40 of 81
Quote:
Originally Posted by Bill Fitzmaurice View Post

Omni-directional is just that, expanding in all directions equally. No matter how many drivers or ports you have or which way they face the output pattern in the subwoofer bandwidth will be the same.
They will. This is why:
http://www.trueaudio.com/st_spcs1.htm
The only exception to spatial loading rules is when the enclosure is large enough that the output is directional, and the output wave cannot wrap around the speaker to then reflect off boundaries behind the speaker. With subs small enough to fit in a home that does not occur.

Thanks Bill !
post #41 of 81
Quote:
Originally Posted by countryWV View Post

Dude they keep stating facts to you. Facts are not agreeable or disagreeable they are facts. You simply just disregard this information as if it were an opinion. I know you are not purposely trying to be disruptive but your continuous posts show that you clearly do not understand the basic knowledge one needs to debate this subwoofer with science and facts.
The sooner the Light Bulb goes off over your head the better the discussion can be had about this subwoofer.
I am just glad that you are having this debate in the proper thread and I also give you credit for remaining positive with your posts and not letting it turn negative.
Enjoy
Chris

I'm not sure why you feel the need to watch my every post ? and if you have nothing to add to what has indeed turned into a healthy discussion on the topic at hand why chime in a disrupt it ! I claim nothing and I know what it would take hit reference levels at all the frequencies on a given disc in a given room with given dimensions etc... . that's not my question! I'm trying to get a respected opinions from those in the know about the DXD12012's abilities , without you can get more for less and not for that kind of money! sometimes you pay a little more for what you want. All things in gathering data online even the purported facts change! and is the reason for the forum itself! wink.gif

And i'll be heading over to the Master bass list thread next if you want a heads up on where I'll be biggrin.gif
post #42 of 81
Quote:
Originally Posted by bossobass View Post

To correct you on one point; all amplifiers employ limiters. Hard, soft, progressive, clip, voltage peak, etc., needs to be qualified, but all of them have blocking caps and limiters.
My point was aimed at Fitz's claim that all subwoofers benefit equally from corner loading. Josh clearly proves that is not true with a single, simple exercise. The FF sub shows 12dB swings placed in the same corner. I would call that significant. My own tests (all in-room and far more comprehensive than the one I cited from Josh) show similar results. Again, the point being that all subwoofers do NOT benefit equally from corner placement.
I think the confusion here is the whole "My sub handled WOTW at reference level with no problems" thing. In AF's defense, this is not a new problem. Folks have been claiming that since the movie was released on DVD a decade ago.

Heck, Josh made similar positive subjective comments in the discussion of his review of the P'digm Sub 2 regarding its heavy use of limiters and no one broke his balls like they are here with AF. wink.gif

I know of no subwoofer system on this planet that "handles" WOTW with no problems in the defined sense of full BW playback with no distortions (save a +/-3dB FR non-linearity). Some will claim the TRW can, but that will have to be shown to me with the appropriate data.

The key word here is "handle". Sub owners really mean that their subs didn't explode or make bad noises or catch fire. They generally have no earthly idea what playback of WOTW at reference level means, and that includes the double-octo 18" build with multi-5 figure watts systems.

One reason I know this to be true is that in all of the thousands of references to scenes in WOTW, the most difficult scene in the movie to reproduce "with no problems" is never mentioned at all. That simply tells me that all of the subs that had "no problem" with WOTW at 0dBRL simply did not even approach playback of that scene in flat full BW with no distortions.



As you can see, although my system "handled" this scene, it did so 'only' down to around 4 Hz, but still left 2 octaves on the table. eek.gif

It wouldn't matter if I had 60 15s and any # of watts, the signal simply is not getting to the drivers for them to react to.

I have to admit that I'm partial to anyone who has the sense to know that stacking, specific driver config, no HPF, sealed systems are a necessary part of the formulae for successful design. But, that's where it ends for me in this case. I'm a decade ahead of KK in this arena and I really need to see more specifics regarding the "Transflux Photon Injector Warp Drive Eco-Flush Driver Loading", or whatever the he!! it's called before I'd offer any actual specific opinions.

Just quickly looking at the review FR graph and assuming it's accurate (which I do not), the sub would not yield a flat response to 10 Hz in my room without some post-PEQ doctoring:

(KK in black, Raptor in green)



KK claims low 500s CM^2 Sd (a pair would have more surface area than a UXL-18), but doesn't mention throw (to calc displacement), so how many might be needed is a missing variable, but $/dB is a tough one to nail down. It can be free and matter not if it can't reach the bottom octaves for any # of reasons (sig chain roll off, not enough power, etc.).

Great stuff! cool.gif
post #43 of 81
Quote:
Originally Posted by audiofan1 View Post

Great stuff! cool.gif
Ah, progress folks!. So you understand now why you cannot play these 5 star movies and appreciate it like others that have much more capable sub systems?
post #44 of 81
Quote:
Originally Posted by Luke Kamp View Post

I have done the tests with rotating subs in my room:
The main effect you'll see rotating subs at the corner or wall versus aimed out isn't in the low end, but in the above bandwidth harmonics that all direct radiating subs create. Those harmonics are directional, and when the driver is aimed away from the listener they are acoustically filtered. Another potential issue is if the combination of the depth of the sub and the distance from the wall results in Allison Effect cancellation when the driver is aimed outward. That total distance must be at least 2.8 feet to result in cancellations at even100Hz, so it's a rare circumstance, but not unheard of. Another factor arises when the driver or port is aimed at the wall and placed close enough so that the volume of air between the cone, or port, acts as a virtual extension of the cabinet. This doesn't affect gain per se, but it can lower the tuning, and therefore low frequency extension, of the sub. Finally, there's the issue of finite sensitivity. It's complicated, but suffice it to say that the lower the sub goes the less gain will be realized by boundary loading. Conversely, the higher the sub F3 the more gain that will be realized in the lower end of the passband. But none of these effects have anything to do with spatial loading.
post #45 of 81
Quote:
Originally Posted by Bill Fitzmaurice View Post

The main effect you'll see rotating subs at the corner or wall versus aimed out isn't in the low end, but in the above bandwidth harmonics that all direct radiating subs create. Those harmonics are directional, and when the driver is aimed away from the listener they are acoustically filtered. Another potential issue is if the combination of the depth of the sub and the distance from the wall results in Allison Effect cancellation when the driver is aimed outward. That total distance must be at least 2.8 feet to result in cancellations at even100Hz, so it's a rare circumstance, but not unheard of. Another factor arises when the driver or port is aimed at the wall and placed close enough so that the volume of air between the cone, or port, acts as a virtual extension of the cabinet. This doesn't affect gain per se, but it can lower the tuning, and therefore low frequency extension, of the sub. Finally, there's the issue of finite sensitivity. It's complicated, but suffice it to say that the lower the sub goes the less gain will be realized by boundary loading. Conversely, the higher the sub F3 the more gain that will be realized in the lower end of the passband. But none of these effects have anything to do with spatial loading.

Thanks for the incite and reasoning Bill, much appreciated. I am just going off of what I have seen. We rotated a jtr captivator in user name Archaea's room and filled in a ~65hz dip close to mid wall up front. Also with a cap in user name Carp's room we turned towards corner from front firing in corner with better results. We then tried that excercise when he changed to a couple submersives with no change with rotation. He now has 8 18" arrayed across the front so no issue's now. We also turned dual captivator S2's in user name dlbeck's room from front firing to side firing on front wall and it filled in a 6db null that I believe going off memory was ~60hz as well. All subs were all the way up against the room boundary or corner. I did an excercise in my room with a sub rotating 90 degrees all the way around with 4 measurements. I trust that Ricci's tests were well controlled and his show changes of 5 db at 32hz on the Rythmik fv15 HP in one port mode.

http://www.data-bass.com/data?page=content&id=77#!prettyPhoto

Unfortunately my laptop failed a month ago and I recently got a new one. Archaea is a computer guy and is going to help me transfer some stuff from my old one, and if I can get the measurements saved on my old computer transfered I would be happy to post my findings if I can dig them up. smile.gif

Edit: I found one i had online. Single mic location same point, front firing (black) to side firing (red) against wall.

Edited by Luke Kamp - 8/19/13 at 11:29am
post #46 of 81
Quote:
Originally Posted by dominguez1 View Post

Ah, progress folks!. So you understand now why you cannot play these 5 star movies and appreciate it like others that have much more capable sub systems?

Uhh! boy here we go rolleyes.gif that was never the question and understood that already , now run along and those who are actually capable of providing insight on the questions at hand talk tongue.gifbiggrin.gif
post #47 of 81
Quote:
Originally Posted by audiofan1 View Post

I'm not sure why you feel the need to watch my every post ? and if you have nothing to add to what has indeed turned into a healthy discussion on the topic at hand why chime in a disrupt it ! I claim nothing and I know what it would take hit reference levels at all the frequencies on a given disc in a given room with given dimensions etc... . that's not my question! I'm trying to get a respected opinions from those in the know about the DXD12012's abilities , without you can get more for less and not for that kind of money! sometimes you pay a little more for what you want. All things in gathering data online even the purported facts change! and is the reason for the forum itself! wink.gif

And i'll be heading over to the Master bass list thread next if you want a heads up on where I'll be biggrin.gif
Alright man I give up.smile.gif
Chris
post #48 of 81
I am sure the KK is a great sounding sub. It would more of them to hit reference than say a Submersive so the costs goes up even more. From the measurements it shows that the DXD rolls off pretty good so for one to experience the single digits it needs much more boost down low which in turns means even more subs to get enough displacement. I love Kreisel products, it introduced me to awesome HT sound and I had 7 S-5000's and dual MX-5000's! It was a great system however I have moved beyond it's capabilities. I got the same thing for my CHT subs because they rolled off more than other subs but with enough displacement and boost I got there with great results but I needed multiples and they were dual opposed 18's!
post #49 of 81
Quote:
Originally Posted by MKtheater View Post

I am sure the KK is a great sounding sub. It would more of them to hit reference than say a Submersive so the costs goes up even more. From the measurements it shows that the DXD rolls off pretty good so for one to experience the single digits it needs much more boost down low which in turns means even more subs to get enough displacement. I love Kreisel products, it introduced me to awesome HT sound and I had 7 S-5000's and dual MX-5000's! It was a great system however I have moved beyond it's capabilities. I got the same thing for my CHT subs because they rolled off more than other subs but with enough displacement and boost I got there with great results but I needed multiples and they were dual opposed 18's!

Quick question MKtheater, since you have some familiarity with Ken's subs especially since the DXD12012 is essentially an MX5000 mk3 with more power and the ability to dig deep and an updated driver radiation pattern , The first question I have is when you guys refer to the ability to play single digits are we talking a given level that you guys are referring to reference say 105db at 5-7 hz or that the DXD12012 can't reproduce those levels at all or just not loud enough? What is the reference concerning ultrasonic frequencies since most mixing studios don't even have subs that play that low. The DXd12012 has been measured to have output as low as 2.5 hz. fill me in wink.gif
post #50 of 81
Loudness, not extension. If one plays reference levels and a signal requires say 0 dBFS at 5 hz just from a single channel(LFE) then the sub is required to play 115 dBs at 5hz at the LP. Well, can a sub do that and with little or clean enough THD to get there? There just is not enough power for DXD to play that loud at 5 hz even if the drivers could handle it. It has been a while but I think the MK 5000 measured 100 dBs at 20hz and this measures 104? I am not sure if the test were similar so that is just some figures. It is very easy to measure your sub and see I it compresses or has high THD at whatever frequency at your LP. The way I see it is if can reproduce a sine wave at 10hz with 10% THD at 115 dBs then a movie will be no problem. You will be surprised though how much displacement and power it really takes to get clean though(10% and under is clean sounding and higher depending on the harmonics). Anyways, DXD sub looks awesome and the stacking ability is great but people around here are used to big ID subs with lots of output for cheap prices and why you get some crap. Lots of people with ported subs say WOTW is played easily at reference as well and there is no way a ported sub can reproduce any if the ULF without 100% THD so they are feeling something, it is harmonics. Hey, if it sounds great who are we to say it sucks or not clean, to each their own.
post #51 of 81
Quote:
Originally Posted by MKtheater View Post

Loudness, not extension. If one plays reference levels and a signal requires say 0 dBFS at 5 hz just from a single channel(LFE) then the sub is required to play 115 dBs at 5hz at the LP. Well, can a sub do that and with little or clean enough THD to get there? There just is not enough power for DXD to play that loud at 5 hz even if the drivers could handle it. It has been a while but I think the MK 5000 measured 100 dBs at 20hz and this measures 104? I am not sure if the test were similar so that is just some figures. It is very easy to measure your sub and see I it compresses or has high THD at whatever frequency at your LP. The way I see it is if can reproduce a sine wave at 10hz with 10% THD at 115 dBs then a movie will be no problem. You will be surprised though how much displacement and power it really takes to get clean though(10% and under is clean sounding and higher depending on the harmonics). Anyways, DXD sub looks awesome and the stacking ability is great but people around here are used to big ID subs with lots of output for cheap prices and why you get some crap. Lots of people with ported subs say WOTW is played easily at reference as well and there is no way a ported sub can reproduce any if the ULF without 100% THD so they are feeling something, it is harmonics. Hey, if it sounds great who are we to say it sucks or not clean, to each their own.

I see where you guys are coming from, It was all wording thing and I knew if I kept asking in slightly different ways I might get some answers. i do plan on seeing what it does in the room as part of the upgrade I did last year was a laptop as well. Trust me I know all too well and I don't even want to go the DIY route to flesh out 5 hz at 115 db! as it would be a complete disaster as far as room vibrations ( which are already enough) which is enemy number one for me, and in all honestly it's something I wouldn't use enough. As things are I'm good, the lows for now for movies and my occasion organ fetish is satiated. I'll add a second DXD12012 down the road as what it would add is more than enough for my listening needs. I had Seaton on my list for a reason and it wasn't for output but because of how owners said it sound and its the main reason I chose the DXD and would again! especially if told you what I paid for it biggrin.gif

when I finally get around to the measurements I'll post the info!

Thanks for hanging in there ! wink.gif
post #52 of 81
Remember that only some movies will even want that high of ULF to be reproduced anyways. Some of us just want to make sure we get everything just in case. At least the DXD has the ability to get there in multiples and I know KK makes great sounding subs, he always has. I have gone DIY for many years now and would be very hard for me to justify any commercial product. BTW, it is not fair to compare a ported sub tuned near 20hz against a sealed sub at 20hz, who says 20hz is where it matters? How about 10hz, the DXD would not only have more output but be much cleaner doing so.
post #53 of 81
Quote:
Originally Posted by Bill Fitzmaurice View Post

Omni-directional is just that, expanding in all directions equally. No matter how many drivers or ports you have or which way they face the output pattern in the subwoofer bandwidth will be the same.
They will. This is why:
http://www.trueaudio.com/st_spcs1.htm
The only exception to spatial loading rules is when the enclosure is large enough that the output is directional, and the output wave cannot wrap around the speaker to then reflect off boundaries behind the speaker. With subs small enough to fit in a home that does not occur.
Thanks for the link, Bill smile.gif


Just to confirm with what is a surely a stupid question...

We are therefore saying that on a sealed push-pull design where one driver is front firing and one driver is down firing (such as on the KK) it does not matter whether you 'port' the bottom sub (by joining/sealing 3 of the box walls with the floor and leaving the 4th open so the soundwaves can only travel out of the front of the box) or leave it free to fire in all directions (by having just 4 support posts and a base plate, such as the downfiring ported SVS subs) because the wavelengths are so long that they 'wrap round' the box and will still bounce off the wall(s) behind the box, even from the front firing driver?
post #54 of 81
Quote:
Originally Posted by MemX View Post

the wavelengths are so long that they 'wrap round' the box and will still bounce off the wall(s) behind the box, even from the front firing driver?
That's it in a nutshell. At higher frequencies the waves don't wrap around the box, see: baffle step. For a sub to work even near, let alone above, the baffle step frequency it would have to be huge.
post #55 of 81
Thanks, Bill, that's helped confirm that I will just do 4 corner supports rather than faffing around with walls and attempting to 'aim' the soundwaves in my push-pull box design with one DF and one FF that I'm attempting to work up smile.gif
post #56 of 81
Quote:
Originally Posted by audiofan1 View Post

an updated driver radiation pattern
What updated driver radiation pattern? It's OMNI like all subs that are physically small relative to wavelengths reproduced.
post #57 of 81
Quote:
Originally Posted by A9X-308 View Post

What updated driver radiation pattern? It's OMNI like all subs that are physically small relative to wavelengths reproduced.

oh its magical like me lucky charms.
post #58 of 81
I'm starting to think you guys are a we bit jealous tongue.gifbiggrin.gif
post #59 of 81
Not in the least. Just answer the question.
post #60 of 81
First you should try a little tact, and not so forceful , as I owe you no answers and this is not truth or dare. Now having said that perhaps we can discuss the post as respectful gents smile.gif I'm not sure if you knew how the MX5000sf was designed but it had the same push pull configuration with one of the 12" drivers firing forward, while the other used its back wave as it was mounted upwards into the bottom of the box, there was a slot in the bottom front of the box just below the forward firing 12" driver. The DXD12012 still retains the push pull design but instead of a forward firing driver, it's a side firing 12" driver, the bottom driver is the same as the older design, however the box itself has larger slots that run the length of the cabinet on three sides including below the side firing 12" driver. looking at the sub from the front nothing comes at you! This is the radiation pattern I was referring to, as to how it goes about get it into the room as the methods can vary of doing so!
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AVS › AVS Forum › Audio › Subwoofers, Bass, and Transducers › Test of the Top of the Line M&K DXD 12012 Sub up at Sound&Vision magazine