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Ported dual 18 RVP18 build thread
Ported dual 18 RVP18 build thread
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Old 28th June 2018, 03:20 PM   #21
conanski is offline conanski  Canada
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Originally Posted by SpeakerBuilderMello View Post
I'd rather run one cord to one sub instead of two cords tbh,
No problem, that is where NL4 speakons and 4 core speaker wire comes in. Most modern amps will have both channels available at one of the rear panel speakon connectors for connecting a speaker in Bridged mode or Bi-amp mode.


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Originally Posted by SpeakerBuilderMello View Post
Problem with gsubs is that someone else already made them. Call me crazy but if I make a sub I'd like to actually say I made it or helped develop it instead of just copying someones designs and claiming credit. Plus if I like it and want to build more then 4 I can do that and avoid legal issues if that ever happens in the future.
I hear you, but the G sub is nothing special it's just a good example of a reflex design that has been published on the web free for anybody to use, you're in no danger of copyright infringement by using it. If it turns out that box isn't ideal for these drivers then build your own.
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Old 28th June 2018, 03:42 PM   #22
conanski is offline conanski  Canada
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OK I just ran a sim in WinISD based on those published specs and the software says this driver won't take much power before exceeding xmax.. only 100 watts in this case. I suspect you only entered the basic parameters for your simulation and that is why it's not showing accurate results.
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Old 28th June 2018, 04:19 PM   #23
theSuede is offline theSuede  Sweden
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I think we have a problem with communication levels here, not uncommon in specialist forums (I'm part of quite a few...)

'Mello is looking to build something that satisfies his needs, with the gear he's already got. Not creating the ultimate small-medium venue low end PA showpiece (at least not as I read his intentions...).

In that case, with an excursion/power limited driver set I would recommend going with slightly smaller cab volume - than what the "ideal" says - and tune the port(s) slightly lower than the "ideal" for flat response frequency in that box volume.

Yes, you get some extreme low end fall-off in response (that you can EQ carefully if you really want to, and find that you rarely/hardly ever get close to x-max limits in real world use) - but in a small venue or even a home environment (?) that rarely makes much difference.

As we all know, unless you're placing the rig outside on a huge flat field, room interactions will largely dominate the 25-80Hz real world response. As long as you can "load" the room you're in "well enough", you get plenty of low bass.

Anyway, my other recommendation would be to try to keep the mounting surfaces for the driver AND the ports as flexible or "remodel friendly" as you can. You never know when a much better driver ends up in your lap (or on bargain-level sale!) - and you might want to change your port tuning later. Both in the case of a new driver, and if you want to "change" the system due to stuff you find out in real world usage.

The new Dayton Audio PN395-8 takes a LOT more power, but doesn't have much more linear excursion - and it's on introduction sale for 149USD (Parts Express). For deeper bass (less power capability for the 80-120Hz slam, but 11mm of usable excursion) with some eq, you have the Dayton Audio PA385S-8 that normally sells for ~199USD

Personally I prefer two or even three ports. Unless you do a slit port, which basically has the same effect.
One large round port has the lowest flow resistance for the non-turbulent region (low power levels and m/s port flow air speeds). That means you get very, very, VERY slightly more acoustic output around the port tuning frequency - but a very nasty turbulence collapse when approaching max levels for the port.
Several smaller ports (with the same total flow section area) have more laminar flow resistance - you might lose 0.5-1.0 dB of port output at the tuning freq, at LOW power levels. But the behavior when the going gets on with it and you crank it real loud is very different. The transition to turbulent flow is slower, and you can push more power through the speaker before the port flow collapses into blocking. Not much difference, but I still find it worth the tradeoff.
For both ways to do it, the port terminations are very important. You don't need huge round-off flares (in fact, for large ports that is sometimes worse than "no" flare, a sharp port termination). A small flare with a small-radius roundoff at the termination can get you 1-3dB more of usable port output, and less port noise.
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Old 28th June 2018, 04:30 PM   #24
conanski is offline conanski  Canada
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At 600w it's hitting 13mm which is roughly 1/2", that won't look like much but I bet it's precariously close to hitting the backplate. But the drivers seem to handle that much power now so what's the problem? All new the suspension is pretty stiff but it will loosen up as the driver breaks in over a few hours of use and you will find it will handle less and less power as that happens.



My simulation is in a 16 cu/ft box tuned to 32hz, I played around with it and a smaller box doesn't seem to help much, IMO a 32 cu/ft double 18 is rediculously big, that is double the size of my 218 subs. I know those drivers are cheap but is portability any concern for you?


So what are possible alternatives. I don't know if you are aware of these places so I'll post up links, these are canadian speaker components and electronics distributors.
Canada's Largest Inventory of Celestion, B&C and Eminence speaker drivers. If you get redirected to McBride Loudspeakers click on the "Retail Customers click here" link at the top right corner of the page.

Accueil
This is a Montreal based surplus company that sometimes has great deals on name brand components.

Last edited by conanski; 28th June 2018 at 04:38 PM.
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Old 28th June 2018, 05:18 PM   #25
conanski is offline conanski  Canada
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Parts Express in the US also has some interesting buyouts, the B52 18-190s is an OEM from Eminence that looks very decent. I modeled it in a 4.2 cu/ft box tuned to 40hz where it produces 123dB with 600w. A pair of these in an 8.4cu ft box produces 130dB with 1200w, that would be a really easy box to move and these drivers will have full control at that power level. B-52 18-190S 18" Cast Frame Professional Subwoofer 8 Ohm

Last edited by conanski; 28th June 2018 at 05:22 PM.
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Old 18th July 2018, 12:01 AM   #26
SpeakerBuilderMello is offline SpeakerBuilderMello  Canada
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Originally Posted by conanski View Post
Parts Express in the US also has some interesting buyouts, the B52 18-190s is an OEM from Eminence that looks very decent. I modeled it in a 4.2 cu/ft box tuned to 40hz where it produces 123dB with 600w. A pair of these in an 8.4cu ft box produces 130dB with 1200w, that would be a really easy box to move and these drivers will have full control at that power level. B-52 18-190S 18" Cast Frame Professional Subwoofer 8 Ohm
First off sorry for the late replies everybody I've been stupid busy as well as rethinking some of this, so I haven't spent any extra time crunching numbers or playing with winisd. I "DID" however buy a rta-m from dbx to go with my dbx 260 so instead of just asking people to take my word for things that these subs make bass, I should have some solid proof soon since I have a show at the end of this month where I am going to hookup everything, outdoors and use it for 2-3 days straight so I'll have plenty of time to test it and play around with it if I can get the mic here in time for it. (shipping may come just after and that would suck!)

To address your comment tho, I had a pair of these exact subs and they blew on the ep4000 with regular use. When I say blow, I mean the voice coils fried, I opened them up to see what was up and the coil was burnt af and unwinding. Many years ago when I first got started I had a pair of behringer euro power 18s and a pair of extremely old crate 18s with blown drivers (one was blown, other had a rip in the cone but still worked and was 4ohm so I never used it, still got it funny enough) anyways I put the b52s in the crate cases (square boxes with 4 circle ports, one in each corner) and tbh the behringer subs where just as loud, I did testing where I would turn the b52s off while playing the behringers and you could barely tell they where off or on. I ended up getting rid of them all when I got my double 18s. When I first got my double 18s they came with 3 discontinued drivers and one empty hole so since I couldn't get a 4th matching sub, I cut the cone of the b52 behind the dust cap, removing the voice coil and bottom spider so the cone hung freely and used it as a passive radiator till I got replacement subs for it that where matching.

Not sure I'd ever feel good about buying a b52 again, specs are lies from what I can tell, these rockvilles bump harder from what I can tell.
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Old 18th July 2018, 12:28 AM   #27
SpeakerBuilderMello is offline SpeakerBuilderMello  Canada
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Join Date: May 2018
Quote:
Originally Posted by theSuede View Post
I think we have a problem with communication levels here, not uncommon in specialist forums (I'm part of quite a few...)

'Mello is looking to build something that satisfies his needs, with the gear he's already got. Not creating the ultimate small-medium venue low end PA showpiece (at least not as I read his intentions...).

In that case, with an excursion/power limited driver set I would recommend going with slightly smaller cab volume - than what the "ideal" says - and tune the port(s) slightly lower than the "ideal" for flat response frequency in that box volume.

Yes, you get some extreme low end fall-off in response (that you can EQ carefully if you really want to, and find that you rarely/hardly ever get close to x-max limits in real world use) - but in a small venue or even a home environment (?) that rarely makes much difference.

As we all know, unless you're placing the rig outside on a huge flat field, room interactions will largely dominate the 25-80Hz real world response. As long as you can "load" the room you're in "well enough", you get plenty of low bass.

Anyway, my other recommendation would be to try to keep the mounting surfaces for the driver AND the ports as flexible or "remodel friendly" as you can. You never know when a much better driver ends up in your lap (or on bargain-level sale!) - and you might want to change your port tuning later. Both in the case of a new driver, and if you want to "change" the system due to stuff you find out in real world usage.

The new Dayton Audio PN395-8 takes a LOT more power, but doesn't have much more linear excursion - and it's on introduction sale for 149USD (Parts Express). For deeper bass (less power capability for the 80-120Hz slam, but 11mm of usable excursion) with some eq, you have the Dayton Audio PA385S-8 that normally sells for ~199USD

Personally I prefer two or even three ports. Unless you do a slit port, which basically has the same effect.
One large round port has the lowest flow resistance for the non-turbulent region (low power levels and m/s port flow air speeds). That means you get very, very, VERY slightly more acoustic output around the port tuning frequency - but a very nasty turbulence collapse when approaching max levels for the port.
Several smaller ports (with the same total flow section area) have more laminar flow resistance - you might lose 0.5-1.0 dB of port output at the tuning freq, at LOW power levels. But the behavior when the going gets on with it and you crank it real loud is very different. The transition to turbulent flow is slower, and you can push more power through the speaker before the port flow collapses into blocking. Not much difference, but I still find it worth the tradeoff.
For both ways to do it, the port terminations are very important. You don't need huge round-off flares (in fact, for large ports that is sometimes worse than "no" flare, a sharp port termination). A small flare with a small-radius roundoff at the termination can get you 1-3dB more of usable port output, and less port noise.
Do I really need something that can take more power?

I mean I know thats the story I get from everybody, more power is more better... but I don't have more power. I have 2ohm 1200w thats like 300w each speaker, 600w each speaker if I do 4ohm. I could do bridged mode 4ohm at 2400w but then we're talking about much more expensive drivers and alot less of them.

I am doing outdoors, in a field in the forest. So if I had the budget I'd just buy a wall of powersofts m-force 40 inch drivers and call it a day with some powersoft amps... but I don't have anywhere near that budget. But I do have 5x ep2500/4000s, so if I can build a system with these to power them then half the battle is done already, the power end.

Now whenever I say outdoors I always get folks telling me I need like a eightteen sound driver or a powersoft m-force driver or some other high wattage driver. But the reality is that this system is for close range listening from 1 foot upwards to 40 feet away, meaning the listening range is too close for a m-force 40 inch sub that warns people to be at least 20 feet away from it to prevent hearing damage.

Also with that being said I don't need a full range sub, I own kick bins and full range dual 15s, the dual 15s can go from 30hz to 20k hz and the kick bins I normally set them at 50hz or 80hz to 1100-1400hz depending on what I'm doing with them. So I have the chest hitting mids, I'm just missing the extra volume around 30-100hz that I'm trying to fill in on my system.. but without spending a bank, cuz I don't have it. Budget is for sure the #1 concern since I know I can use budget $60 drivers to produce bass at 1-40 feet easily, so it makes more sense to me to expand how wide the wall is to expand the "close range dancing" area then to have one or two high powered subs in the middle that nowhere near as many people can get close to.

So thats why I don't seem to care when people say things like "this one sub can replace 2 or 4 of those rockvilles" cuz its not about max spl at 100 feet and its not about moving as little cabs as possible, or storing as little cabs as possible. I have unlimited storage and I have roadies who help me move things so nothing is too big or too heavy, so the only concern becomes then "is it too expensive to stack many of" ? I mean I want to build at least 8x dual 18s, maybe more, so if I'm spending 750/ea driver for eighteen sound cabs then I'm looking at at least 1800 to build each cab. Where as if I use the rockville drivers thats $60/ea that would cost me maybe $300-350 to make, giving me 6 cabs for the price of 1 cab. Sure on paper the eighteen sound drivers would kick the crap out of the rockvilles, but I have my concerns about sound spread for the dancefloor. I have had high powered 21 inch 2400 subs out before and I was not able to power very many of them, I've also rented a wall of 500w drivers and the wall of 16x 500w drivers was "way" more impressive and had a more "even" sound on the dancefloor then the 21s, the volume from one end of the dancefloor felt alot like the other end and the center, instead of the center being where you mainly feel it and then the sides less so when you only got 1 or 2 high powered subs, less people can get close to it for that "close to a sub" feel. I know this goes verse everything people think here, but I genuinely think having multiple lower wattage drivers spread out is better then having 1 or 2 high powered ones centered together in the middle.

Again since moving them or storing them isn't a issue, these are not reasons for me to think the lower watt is not what I want. The only size requirement I have is that they need to be able to fit through a doorway.

I can't see myself in the future using this system for anything other then close range listening of 1 to 40 feet, so this is the goal I have and the requirements I'm aiming towards, not over those requirements by getting higher wattage drivers that are "better", again I'm not sure I "need" better or can even properly use "better" since I have limited power requirements unless I buy a new amp and I don't plan on doing that when I have so much unused power already cuz I'm a horder and buy all the cheap ep2500/4000s I find on craiglist for $200 or less.

With that all being said, I'm thinking about making a g-sub still or something like it. B&C has a cool design for a single sub that I thought might be a good design for a dual sub if I recalculated the volume and port size.
http://www.bcspeakers.com/media/W1si...2ZpbGUiXV0.pdf

Basicly was thinking that if I tilt two of these cases on their side so the bottom triangle ports where in the center, it would be a dual 18 case and I could take the wheel part off the back and instead put it on one of the ends so I could stand it up and wheel it stood up like the rest of my speakers. I was thinking just making the bottom and top plywood longer and keeping the bottom board that would now be in the center, to seperate the two so it would look like a dual 18, but there would be a board going down the middle of it seperating the two and would have 4 triangle ports in the middle. I kinda like the idea of the triangle ports, it would also be easier to make the port longer with triangle ports by just simply adding another bit of wood to the end on the inside. Haven't had the time to crunch numbers on it yet but I was looking around at 21s for ***** n giggles n came across that that turned into this idea.

Last edited by SpeakerBuilderMello; 18th July 2018 at 12:31 AM.
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Old 18th July 2018, 12:42 AM   #28
SpeakerBuilderMello is offline SpeakerBuilderMello  Canada
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Quote:
Originally Posted by conanski View Post
At 600w it's hitting 13mm which is roughly 1/2", that won't look like much but I bet it's precariously close to hitting the backplate. But the drivers seem to handle that much power now so what's the problem? All new the suspension is pretty stiff but it will loosen up as the driver breaks in over a few hours of use and you will find it will handle less and less power as that happens.



My simulation is in a 16 cu/ft box tuned to 32hz, I played around with it and a smaller box doesn't seem to help much, IMO a 32 cu/ft double 18 is rediculously big, that is double the size of my 218 subs. I know those drivers are cheap but is portability any concern for you?


So what are possible alternatives. I don't know if you are aware of these places so I'll post up links, these are canadian speaker components and electronics distributors.
Canada's Largest Inventory of Celestion, B&C and Eminence speaker drivers. If you get redirected to McBride Loudspeakers click on the "Retail Customers click here" link at the top right corner of the page.

Accueil
This is a Montreal based surplus company that sometimes has great deals on name brand components.
Portiability is of little concern to me.

Those are community 218's your talking about?
http://www.communitypro.com/sites/de...-218S_spec.pdf

I have two of these, stock with stock drivers. They sound pretty good tbh and run really well on the ep4000. I'd buy more if I could get my hands on them, but they are old and discontinued so its doubtful I'll ever get another pair. I was thinking tho that building something smaller like this might be another option, I mean they are around 15-16cu/ft so around half the size of the case I'm thinking bout making. Its hard for me to tell if the 16cu or 32cu is better tho since from all accounts from what I can see I'm getting extra spl/db out of the 32cu at significant levels, but I'm not seeing the down side to going that big.. surely there must be some down sides aside of just being harder to move or store?
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Old 18th July 2018, 02:05 AM   #29
SpeakerBuilderMello is offline SpeakerBuilderMello  Canada
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I know you guys are all gona cringe at this but I was talking to someone who has 21 inch drivers for sale and granted they don't seem like the best thing in the world at 600w/ea they would work decently with my power requirements.

Now I ended up asking where they got them from and they told me a china manufacturer. I've been thinking about maybe looking on some of their sites for wholesale drivers but always thought the rockvilles may be a better option since I can for sure get them in large numbers and don't have to worry about them becoming discontinued.

But I mean at 250 retail for those 21s I figure that means the actual cost has to be more around 100-150 or less or it wouldn't be worth the risk to buy them to profit off of for her. Problem with those drivers in particular is that there is no ts specs, but from what I can see alot of other china manufacturers do include ts specs.

I'd say that would be my max budget tho, spending anymore then 200 on a driver, 400 in total on drivers per cab is about max I would want to spend, ideally half that or less.... So those b52 blowout drivers seem like a good option since they are on sale but I really donno if I wana try another b52, they dont seem to be able to cool themselves off well enough during extended use of 8 to 32+ hours straight, where as I don't have this issue with the rockvilles, the rockvilles have been working longer then the b52s did under the same conditions.

Last edited by SpeakerBuilderMello; 18th July 2018 at 02:08 AM.
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Old 21st July 2018, 03:31 AM   #30
Top Shelf is offline Top Shelf  Canada
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I know your mind is set with using cheap stuff, but my mind has been totally changed when I bought 2 b&c 18" tbw100's, and fed them 3000+ watts.
Absolutely INCREDIBLE bass is all I can say. Good luck!
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