They will have grills, 3/4" expanded steel with acoustic grill cloth behind, I buy that by full sheets & use that approach for all of my cabs. Beer cans, bottles, glassware, shoes, jewelry, underwear, live chickens, the list of stuff I have extracted from ungrilled horns after shows is amazing. And I am fixing a cab for a DJ this week that some drunken child literally kicked in, won't be possible to repeat that damage when I return it to him grilled my way.
Waterproof is a given, that's why I planned on painting both inside and out. That way I have an internal moisture barrier to keep them from degrading from humidity on the inside as well as liquid on the outside. I have seen cabinets mold from the inside in clubs around here. They will also end up mounted at least 3/4" off of the floor to minimize the layer of wet that would never go away if a panel were resting directly on the floor.
MDF is also a given, at least for one cab as a test unit, I must satisfy my curiosity about the sonic differences (if any) between the 2 materials in this sort of cabinet...but the MDF cab would have to display some unexpected dramatic performance difference before final cabs would run the risk of using it as I have always hated the stuff personally. I already have both MDF and Baltic Birch cut for these first 2 test critters. Regardless, with permanent install (never moved cabinets) I can't see the moisture degradation being too much of an issue assuming I have them properly sealed to begin with. Another club in town here has MDF horns with 2 coats of cheap latex paint that have been living there unchanged for 10 years now
Waterproof is a given, that's why I planned on painting both inside and out. That way I have an internal moisture barrier to keep them from degrading from humidity on the inside as well as liquid on the outside. I have seen cabinets mold from the inside in clubs around here. They will also end up mounted at least 3/4" off of the floor to minimize the layer of wet that would never go away if a panel were resting directly on the floor.
MDF is also a given, at least for one cab as a test unit, I must satisfy my curiosity about the sonic differences (if any) between the 2 materials in this sort of cabinet...but the MDF cab would have to display some unexpected dramatic performance difference before final cabs would run the risk of using it as I have always hated the stuff personally. I already have both MDF and Baltic Birch cut for these first 2 test critters. Regardless, with permanent install (never moved cabinets) I can't see the moisture degradation being too much of an issue assuming I have them properly sealed to begin with. Another club in town here has MDF horns with 2 coats of cheap latex paint that have been living there unchanged for 10 years now
One other item in all the simulations what is the off axis response? I am sure that horizontal and vertical are different. I believe the curves given are on-axis and centerline from the driver. You might want to check to see if there is going to be any "suck out" due to phase issues between the two boxes.
Hornresp shows power response I believe, not on axis response. I believe I mentioned this a long time ago, having the horn mouths 16 feet apart is going to create directivity issues at the top of the subs' passband. And depending on where the mains are located the situation might be even worse.
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Imaging and directivity are COMPLETELY different things. And there's no such thing as imaging at subwoofer frequencies anyway.
16 feet between subwoofers is going to cause directivity issues at the top of the subs's passband, no matter if there's 0, 1 or 100 extra subs between the two that are 16 feet apart. This is an issue about physical length vs wavelength.
Anyway, if your room corners are 16 feet apart, that sounds like a seriously TINY room, I thought this was a club. With a room that small I'm not sure directivity would matter too much, but you should probably look it up just to find out what it means if you are working in the industry. (Directivity is aka dispersion, on vs off axis response.)
16 feet between subwoofers is going to cause directivity issues at the top of the subs's passband, no matter if there's 0, 1 or 100 extra subs between the two that are 16 feet apart. This is an issue about physical length vs wavelength.
Anyway, if your room corners are 16 feet apart, that sounds like a seriously TINY room, I thought this was a club. With a room that small I'm not sure directivity would matter too much, but you should probably look it up just to find out what it means if you are working in the industry. (Directivity is aka dispersion, on vs off axis response.)
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I'm well aware of the difference between the two terms, I simply used the wrong word when writing a quick post at 4:30AM at the end of a 22 hour day. Please forgive the error. I know you have quite a bit of knowledge & appreciate your help, but sometimes the your posts seem to carry the assumption that I am a rank tyro. After 30 years of pro audio I miss some things sometimes, but this ain't my first rodeo.
This IS a small room, and it IS a nightclub with a very regular performance schedule of national level Rap, EDM, and recently Country artists. The total depth of the room is only around 40' and choices for cabinet placement are extremely limited. That's why I keep acting relatively unconcerned about the directivity when it is brought up, I've run a batch of room sims & this is the best compromise I could find.
IN theory: While 2 subs 16' apart create one diffraction pattern, famous for the central power alley and the dual 45 degree moire pattern of nulls that becomes more dramatic as frequency approaches a critical wavelength, and this could be problematic even in this short of a presentation space, each additional identical sub betwixt those two that is driven with it's own processing line to allow for discrete delay/phase/eq adjustment can essentially allow some steering and breaking up of those sum and null patterns into finer graduations of softer variation in specific directions until you approach the driver density that will behave as a true line in the relevant frequencies...or an end fire if you have enough space to use it that way, where on the one hand it is a continual mass of cancellation and summation variations, and yet on the other hand they are so complex and subtle that they are resolved as no change in the desired coverage area.
In practice: Currently the club rents additional rig a couple of times a week for those larger shows, the rental subs go roughly where two of the new ones will live & complement the existing house subs which are where the 3rd new one will be. With a bit of tweaking we get a very effective result this way, and the performance difference we are adding will be in the 20-50 Hz range where these 3 subs will be within 1/2 wavelength of each other.
Technically the room corners aren't 16' apart. The actual corners are around 35' apart. But at 16' there is a balcony/2nd floor, so at that point the ceiling height for the rest of the area shrinks to 8' 4", and there is a 4' high bar that is very solidly built that the subs will butt against, exiting along the floor. So the airspace becomes something between corner loaded and wall loaded for those two subs, depends on the frequency in question. The upstairs are has the same overall width as the downstairs/stage, but extends slightly deeper. Didn't I mention early on that the acoustic space was somewhat nightmarish?
This IS a small room, and it IS a nightclub with a very regular performance schedule of national level Rap, EDM, and recently Country artists. The total depth of the room is only around 40' and choices for cabinet placement are extremely limited. That's why I keep acting relatively unconcerned about the directivity when it is brought up, I've run a batch of room sims & this is the best compromise I could find.
IN theory: While 2 subs 16' apart create one diffraction pattern, famous for the central power alley and the dual 45 degree moire pattern of nulls that becomes more dramatic as frequency approaches a critical wavelength, and this could be problematic even in this short of a presentation space, each additional identical sub betwixt those two that is driven with it's own processing line to allow for discrete delay/phase/eq adjustment can essentially allow some steering and breaking up of those sum and null patterns into finer graduations of softer variation in specific directions until you approach the driver density that will behave as a true line in the relevant frequencies...or an end fire if you have enough space to use it that way, where on the one hand it is a continual mass of cancellation and summation variations, and yet on the other hand they are so complex and subtle that they are resolved as no change in the desired coverage area.
In practice: Currently the club rents additional rig a couple of times a week for those larger shows, the rental subs go roughly where two of the new ones will live & complement the existing house subs which are where the 3rd new one will be. With a bit of tweaking we get a very effective result this way, and the performance difference we are adding will be in the 20-50 Hz range where these 3 subs will be within 1/2 wavelength of each other.
Technically the room corners aren't 16' apart. The actual corners are around 35' apart. But at 16' there is a balcony/2nd floor, so at that point the ceiling height for the rest of the area shrinks to 8' 4", and there is a 4' high bar that is very solidly built that the subs will butt against, exiting along the floor. So the airspace becomes something between corner loaded and wall loaded for those two subs, depends on the frequency in question. The upstairs are has the same overall width as the downstairs/stage, but extends slightly deeper. Didn't I mention early on that the acoustic space was somewhat nightmarish?
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Ok, apologies. I have no idea what you know and when you use the wrong terms (especially when the right terms have been used in the previous post) it makes me think you don't know. I had no way to know that you already know about power alleys and steering.
The best solution is to keep the mouths close together but if that's not possible your experience with steering should get at least most of the bass where you need it to go.
Just curious if you have a picture of the extruded metal you mentioned for your grilles?
I am thinking of making a grille for my subs and wanted to know what others used. My area that would be needed to cover is rather large so I though of going with a thicker material to keep the grille from flapping back and forth. PLUS with the grille area having to be at least 64% or higher flow rate I wondered what you might be using. Just curious.
I am thinking of making a grille for my subs and wanted to know what others used. My area that would be needed to cover is rather large so I though of going with a thicker material to keep the grille from flapping back and forth. PLUS with the grille area having to be at least 64% or higher flow rate I wondered what you might be using. Just curious.
@Just a guy- your name is hilariously ironic as you clearly think quite highly of yourself. For all I know that is well deserved (or not). Please consider this: your consistently antagonistic tone is unnecessary. The data you present is good enough to speak for itself and your subjective opinion of your own opinion just makes you come off like a dick. If I look past that you are actually being nice and quite helpful spending time assisting the OP. I have found that approaching such things in a collaborative manner, instead of oppositional, will result in a much higher rate of acceptance of your ideas and people will think more highly of you. You obviously have experience and knowledge, trust in that to convey the merit of your statements and try not to belittle others who may not be as skilled or don't convey their idea correctly.
@OP IMO- you are focusing too much on sub 30hz. I do not know of any EDM that has much content below 30hz but I can appreciate striving for "flat" to 30hz. I think of 20-29hz as being for theater, but that's just me. I would wager a guess that the ensuing rattles in the building from content below 35 would be louder than the frequencies causing them. My suggestion is make your life easier and shorten the horn length a bit. Also the type of EDM that is typical for the venue is a major consideration. House, techno and trance(I call them "4 on the floor" music") rarely hit below 38 and the "transient" nature of the bass makes them much more sensitive to building rattle, in that it can spoil your sound quality. Bass music (dnb dubstep, glitch, etc.) demands extension to at least 36 and tend to mask most rattles unless they have harmonics well over 1k or are narrow q like undamped hvac. But bass music can expose weaknesses in your amps (and/or power distro) that the watt rating doesn't show. 3+seconds of a 30hz square(ish) wave will choke that qsc and it will lose output quickly as the capacitors drain. Put macrotech or crest on a 30 amp circuit(for the older models 20 can fine for newer ones) with the same track and jaws will drop at the difference.
I was also going to mention the sub placement issue. Given the limitations I would try delaying the center sub about 3ms. Situations like that make me wish I could afford EASE. Regarding imaging, I feel strongly that significant misalignment in the time domain of the tops and subs results in poor imaging so IMO subs do play a role in imaging even if its not a stereo perception. When tuning by ear I try to get the kick to sound like its coming from the space between the tops and the subs. Perhaps we could call that vertical imaging as opposed to stereo imaging. I never thought about it this way before, just conveying my train of thought stemming from the discussion.
Lastly, the venue you describe reminds me of this club DNA lounge here in SF. Best of luck, and if you are on the west coast pm me, I'd love to check it out when you get those cabs in.
-Matt
@OP IMO- you are focusing too much on sub 30hz. I do not know of any EDM that has much content below 30hz but I can appreciate striving for "flat" to 30hz. I think of 20-29hz as being for theater, but that's just me. I would wager a guess that the ensuing rattles in the building from content below 35 would be louder than the frequencies causing them. My suggestion is make your life easier and shorten the horn length a bit. Also the type of EDM that is typical for the venue is a major consideration. House, techno and trance(I call them "4 on the floor" music") rarely hit below 38 and the "transient" nature of the bass makes them much more sensitive to building rattle, in that it can spoil your sound quality. Bass music (dnb dubstep, glitch, etc.) demands extension to at least 36 and tend to mask most rattles unless they have harmonics well over 1k or are narrow q like undamped hvac. But bass music can expose weaknesses in your amps (and/or power distro) that the watt rating doesn't show. 3+seconds of a 30hz square(ish) wave will choke that qsc and it will lose output quickly as the capacitors drain. Put macrotech or crest on a 30 amp circuit(for the older models 20 can fine for newer ones) with the same track and jaws will drop at the difference.
I was also going to mention the sub placement issue. Given the limitations I would try delaying the center sub about 3ms. Situations like that make me wish I could afford EASE. Regarding imaging, I feel strongly that significant misalignment in the time domain of the tops and subs results in poor imaging so IMO subs do play a role in imaging even if its not a stereo perception. When tuning by ear I try to get the kick to sound like its coming from the space between the tops and the subs. Perhaps we could call that vertical imaging as opposed to stereo imaging. I never thought about it this way before, just conveying my train of thought stemming from the discussion.
Lastly, the venue you describe reminds me of this club DNA lounge here in SF. Best of luck, and if you are on the west coast pm me, I'd love to check it out when you get those cabs in.
-Matt
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Not sure on what music you listen to or use but there is PLENTY of content below 40hz to make the 30hz extension warranted. While some music does not go below 40hz much, most of the newer tracks of today I have ever listen to go down to 30hz frequently. Add in slowed and other types and now 25hz becomes warranted. So getting off the train at 30hz seems like a good idea.
Either way everyone may need a different setup based on their application.
Either way everyone may need a different setup based on their application.
When I bother to post at all anymore it's very usually in a blunt and factual manner, if you want to characterize that as "consistently antagonistic" that's fine with me. I seriously don't care if you think I'm a dick or how highly anyone thinks of me. This isn't facebook and I'm not asking you or anyone else to "friend" me, this is an educational forum and all that matters is correct information. Feel free to disregard my posts if you don't like me. I don't post much anymore anyway. Usually the people that need the most help are the ones least willing to accept it (not in this conversation but in general) and to be honest, IMO that's their own fault, not mine.
I could say a lot more about this but it doesn't belong here. PM me or start a new thread, that's what you should have done in the first place. I'll address all your concerns honestly, bluntly and factually.
Matt, I see you've been posting here for about 14 months. Never underestimate whom you are conversing with here, this is not the shallow end of the pool.
This is a technical forum which tends to draw audio pro's..........and audio hobbyists with very strong professional and technical backgrounds in areas outside audio. Along with that comes egos, a certain level of impatience, and a detail oriented nature. I'm actually suprised at how well people get along.
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mattlong8: I feel like Just a Guy & I have cleared our air just fine by ourselves, thanks. I have great respect for his opinions & knowledge, & he had no idea what (if any) knowledge I had at the start. It's interesting in context that you assume that I am not aware of the spectral content of various genre of music when I've already satisfied most here that I have at least some working knowledge of and experience with active bass management...one is distinctly more basic knowledge than the other for an old road dog such as myself.
chrapladm: Attached is a pix of the expanded steel grill I made to replace the missing PV grill for a DJ customer, it is the same stuff I use for most of my projects. A local metal supply shop has it in 4x8 sheets for around $70. I use plastic trim for wallboard to cover the sharp bits & give it a nice clean look with no effort. For some projects I'll also spray the back with R77 & stick acoustic cloth to it before the plastic trim goes on.
chrapladm: Attached is a pix of the expanded steel grill I made to replace the missing PV grill for a DJ customer, it is the same stuff I use for most of my projects. A local metal supply shop has it in 4x8 sheets for around $70. I use plastic trim for wallboard to cover the sharp bits & give it a nice clean look with no effort. For some projects I'll also spray the back with R77 & stick acoustic cloth to it before the plastic trim goes on.
Attachments
Got them done, installed, and a solid 'rough tweak' on getting them dialed in. Unfortunately, we did not have time to do our traditional outdoor range test before installation. In fact, so far the rig is entirely set-up & aligned with math off of my models & a quick application of ears for polish. I will try to do some advanced tweaking & testing and post some sub-in-room graphs as soon as I get caught up on the other install stuff that has dropped into our lap as festival season dries up.
Nonetheless, in a nutshell these subs are freaking amazing in this space. I have had sooo many people come up to me with glowing comments. Jesse Marko onstage currently, using tables & having no issues with tracking or skipping, but the LF distorts your vision if you're directly in front of the stage, so I'd say I managed a decent degree of onstage cancellation. And throughout the room I can't find a cold spot so far. Tomorrow is the first live band on the new rig and next Thursday Blau is back here again, the drivers will be broken in by then, so we'll see if we're all still as ecstatic at that point as we are now.
Nonetheless, in a nutshell these subs are freaking amazing in this space. I have had sooo many people come up to me with glowing comments. Jesse Marko onstage currently, using tables & having no issues with tracking or skipping, but the LF distorts your vision if you're directly in front of the stage, so I'd say I managed a decent degree of onstage cancellation. And throughout the room I can't find a cold spot so far. Tomorrow is the first live band on the new rig and next Thursday Blau is back here again, the drivers will be broken in by then, so we'll see if we're all still as ecstatic at that point as we are now.
Congrats on the install.
A little late, but I have been meaning to suggest the possibility using MDO instead of MDF for moisture resistance as a cost effective material. (my uncle was involved with the development of a similar process) Just a thought... That said, with paint technology as good as it is, I am sure MDF will hold up just fine with a good paint job.
A little late, but I have been meaning to suggest the possibility using MDO instead of MDF for moisture resistance as a cost effective material. (my uncle was involved with the development of a similar process) Just a thought... That said, with paint technology as good as it is, I am sure MDF will hold up just fine with a good paint job.
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