Whoa, if I'm looking at that image right, the vented box is taking up your entire trunk. If you still want to keep the back set (which I suggest you do), there's basically no room for a bigger box, which means that you either keep things as-is, or you settle for a TH with higher-efficiency but a higher cut-off point.
In your position, I'd keep the vented box, as it allow you to keep your system 2-way as well.
Good to know you're using car audio amps (hopefully Class D ones too). I've been pushing that idea for years. All one needs to do is up the battery capacity to meet the power and play time requirements. and just run the engine for awhile if necessary to keep the battery or batteries topped up. Much better than having to resort to a noisy generator for your power.
The vented box I have is 140L when it's all said and done (subtracting volume of battery, amps, and other electronic components housed in the sub box. External dims are 39w x 15h x 26d. The baffle is angled to match the rear seats, but I flip it 180 and point it out of the back when in "PA mode".
The compression drivers clip to the roll bar and connect to the sides of the sub box with anderson powerpole connectors for easy disconnection.
The JL amps are nice. They are tested and rated at 1200w actual continuous RMS. They also incorporate a switching voltage regulator that outputs the same power regardless of 1-4ohm speaker connection and 10-16vdc.
Saturday night was the first time I used the setup, and I only had a single 35ah deep cycle at the time. It ran (isolated) without interruption for 2 hours straight at full throttle. The amps are very efficient class d. I paid a pretty penny for them, and I think it was worth the money considering all the built in protection they offer. They also run very cool, barely any power loss from heat. Normally I hate car audio amps! I guess you get what you pay for.
I still want to run some sims, but hearing that very high aspect ratios cause issues is a bit of a bummer. I guess I could always just divide the box into two.
Much more hmmmmm
The compression drivers clip to the roll bar and connect to the sides of the sub box with anderson powerpole connectors for easy disconnection.
The JL amps are nice. They are tested and rated at 1200w actual continuous RMS. They also incorporate a switching voltage regulator that outputs the same power regardless of 1-4ohm speaker connection and 10-16vdc.
Saturday night was the first time I used the setup, and I only had a single 35ah deep cycle at the time. It ran (isolated) without interruption for 2 hours straight at full throttle. The amps are very efficient class d. I paid a pretty penny for them, and I think it was worth the money considering all the built in protection they offer. They also run very cool, barely any power loss from heat. Normally I hate car audio amps! I guess you get what you pay for.
I still want to run some sims, but hearing that very high aspect ratios cause issues is a bit of a bummer. I guess I could always just divide the box into two.
Much more hmmmmm
The JL amps are great, have experience with the other / amps.
my box is about 190 liters after construction (per driver).... If you are saying your boxes (combined) are 140liters net then TH is not an option for your desired LC. but it sounds like you could make your Vented boxes bigger if thats the case 🙂
my box is about 190 liters after construction (per driver).... If you are saying your boxes (combined) are 140liters net then TH is not an option for your desired LC. but it sounds like you could make your Vented boxes bigger if thats the case 🙂
Cool stuff. For my somewhat smaller tote around PA system (hey, smaller car=smaller system, LOL), I went with Alpine class D amps and the Pioneer DEH-80PRS head unit. The DEH-80PRS, with time alignment, 16-band EQ and individual HP and LP filters has all the processing I need, well except perhaps for limiting, and the Alpine amps have these quick-release connectors rather than screw-down terminals for the speaker outputs, so with a few extra connectors it's easy to swap out the connections for the car audio system with those running to the PA system can connected via standard speakON connectors.
What do you use for your source? I usually let other people "DJ" by hooking their laptops, iPads, etc. into the deck via RCA, BT or USB. Of course I keep the remote-control for the head unit... 🙂
What do you use for your source? I usually let other people "DJ" by hooking their laptops, iPads, etc. into the deck via RCA, BT or USB. Of course I keep the remote-control for the head unit... 🙂
This thread isn't about car amps so you can ignore this post if you want but your amp seems too small unless you are more concerned with battery life than spl potential.
The sim I provided a few posts ago was at about 1100 watts and used one driver, so 2200 watts for 2 drivers to reach xmax in that design. For your current ported box (which is physically smaller and tuned higher) it will almost certainly need even more power than that (possibly quite a bit more) to reach xmax. By doubling your amp power you could probably see 3 db in gains minus a small amount of loss to power compression.
Your amp does seems nice but you don't need equal power output regardless of impedance or power supply voltage UNLESS you are constantly switching subs or have a severely inadequate power supply, in which case I'd save the money with a cheaper amp and spend it on the power supply every time. You could get a lot more power for a lot less money.
I don't trust any manufacturer published specs for any car audio equipment unless independently verified by a reputable 3rd party and that info can be hard or impossible to find, so for car amps I look for amplification class, fuse rating and recommended power wire gauge to get a realistic estimate of how much power the amp can put out.
Your JL amp is class D, the recommended minimum power wire is 4 gauge and fuse is 100 amp.
Here's a class D amp with 160 amp fuse rating and no specific minimum power wire recommendation in the manual other than mentioning 4 gauge or higher should always be used. This $160 amp very likely outperforms the JL amp and for the price of the JL you could buy another one of these and strap them for double the power and then buy another 4 more to keep in the closet in case one of them ever breaks.
Planet Audio AC5000.1D Class D Mono Amplifier 5000W Max
I had a Planet Audio amp last year (2006 model BB1250.1) that was independently tested to meet or exceed it's specs, and the same internals were also used by other higher tier brands with a different case and sold for a LOT more money so I don't discriminate based on brand.
Or if you want a more highly regarded brand name there's this class D guy with 300 amp fuse rating and minimum 1/0 (0 gauge) power wire recommendation meaning at least double the output of the JL for half the price.
Hifonics Atlas Mt. Olympus 3000W Monoblock Class-D Amplifier
These last 3 recommendations are not as important for a fully contained battery operated system, but for max performance I would also recommend doing the Big 3 wiring upgrade in the vehicle with at least 0 gauge wire.
And I'd check your alternator specs to find out if 140 is spec'ed at peak or at idle and if it's an idle rating what rpm the spec is measured at and what rpm your vehicle idles at. (Or just measure the output at idle.) If it's a peak spec it's possible that it's only producing a couple hundred watts (or even less) at idle. It's most likely a peak spec but even if it's not 140 amps * 12 volts is 1680 watts so there's room for improvement here too.
And finally, more batteries is always better, especially when they are not being charged.
The sim I provided a few posts ago was at about 1100 watts and used one driver, so 2200 watts for 2 drivers to reach xmax in that design. For your current ported box (which is physically smaller and tuned higher) it will almost certainly need even more power than that (possibly quite a bit more) to reach xmax. By doubling your amp power you could probably see 3 db in gains minus a small amount of loss to power compression.
Your amp does seems nice but you don't need equal power output regardless of impedance or power supply voltage UNLESS you are constantly switching subs or have a severely inadequate power supply, in which case I'd save the money with a cheaper amp and spend it on the power supply every time. You could get a lot more power for a lot less money.
I don't trust any manufacturer published specs for any car audio equipment unless independently verified by a reputable 3rd party and that info can be hard or impossible to find, so for car amps I look for amplification class, fuse rating and recommended power wire gauge to get a realistic estimate of how much power the amp can put out.
Your JL amp is class D, the recommended minimum power wire is 4 gauge and fuse is 100 amp.
Here's a class D amp with 160 amp fuse rating and no specific minimum power wire recommendation in the manual other than mentioning 4 gauge or higher should always be used. This $160 amp very likely outperforms the JL amp and for the price of the JL you could buy another one of these and strap them for double the power and then buy another 4 more to keep in the closet in case one of them ever breaks.
Planet Audio AC5000.1D Class D Mono Amplifier 5000W Max
I had a Planet Audio amp last year (2006 model BB1250.1) that was independently tested to meet or exceed it's specs, and the same internals were also used by other higher tier brands with a different case and sold for a LOT more money so I don't discriminate based on brand.
Or if you want a more highly regarded brand name there's this class D guy with 300 amp fuse rating and minimum 1/0 (0 gauge) power wire recommendation meaning at least double the output of the JL for half the price.
Hifonics Atlas Mt. Olympus 3000W Monoblock Class-D Amplifier
These last 3 recommendations are not as important for a fully contained battery operated system, but for max performance I would also recommend doing the Big 3 wiring upgrade in the vehicle with at least 0 gauge wire.
And I'd check your alternator specs to find out if 140 is spec'ed at peak or at idle and if it's an idle rating what rpm the spec is measured at and what rpm your vehicle idles at. (Or just measure the output at idle.) If it's a peak spec it's possible that it's only producing a couple hundred watts (or even less) at idle. It's most likely a peak spec but even if it's not 140 amps * 12 volts is 1680 watts so there's room for improvement here too.
And finally, more batteries is always better, especially when they are not being charged.
Battery life might also be halved in the process of trying to get that extra 3dB that way.
Most good car audio manufacturers quote CEA 2006-compliant ratings for their amps, JL included. As for my Alpines, they come with "birth-sheets" showing their actual measured output.
That's not really a good way to do it IMO. For example, there's nothing stopping ElCheapo from putting 200W of nice shiny fuses into a crappy amp to make you think it's more powerful than it really is, LOL. Don't laugh - there are stories of people making their amps bigger and heavier because bigger and heavier was once equated with being more powerful.
Another thing - for mobile PA use off of battery power, what's also quite important is how much power the amplifier consumes at idle. Peak efficiency for class D is achieved at peak output, and it drops as output decreases. So unless the intent is to run continuous sine waves at peak level, that idle power may have a noticeable impact on run-time as well. This tends to go UP as amplifier capacity increases, so yes, it is possible to size an amp too big for this particular type of use.
What I'm basically trying to suggest is that I think the poster will have to carefully weigh if it's worth upgrading the electrical supply, the alternator, add extra batteries and change out the amps for what may actually amount to less than 3dB of additional linear output capability.
Aspect ratio is not a simple issue. There are at least two factors to consider - air velocity in that point in the enclosure and the ratio of cross sectional area to boundary circumference at that point in the enclosure. There's a third component too which is indirectly related that I will address at the end since it could affect your specific design as drawn.
The reason high aspect ratios cause issues is because of boundary layer friction in which the air closest to the walls does not move as freely as the air in the middle of a duct, and the problem gets worse (the boundary layer gets thicker) as air velocity increases. This means that the higher the ratio of cross sectional area to boundary circumference the better the air will flow. So at high velocity a circular tube will perform better than an elongated rectangular tube with the same cross sectional area because there's less air in direct contact with the walls. But at low velocity this isn't much of an issue and since the throat is usually the most likely place to have the highest aspect ratio and since velocity isn't usually very high in the throat area (assuming the compression ratio is not too high and the throat is not a whole lot wider than the driver) aspect ratio may not even be an issue.
In this light, dividing the box into two would be slightly worse, not better, because it increases the boundary circumference (the two separate throats would have a greater total circumference than a single undivided throat) while maintaining the same cross sectional area.
Now the issue gets slightly more complicated because boxes need braces, and solid braces provide more wood surface area in the duct path and all internal surface area has boundary layer friction. So dividing the box is very much like having solid bracing down the length of the enclosure. Dividing the box into two OR having solid bracing down the length of the horn BOTH decrease the aspect ratio (which by itself isn't actually the problem) BUT make the boundary layer friction issue worse by introducing more boundary layer area (which is the problem).
In the box dimensions you have chosen there is no simple way to decrease the amount of boundary layer circumference so I wouldn't worry about it too much.
Now the third issue is not directly related to aspect ratio but it is an issue indirectly related in the layout you have drawn. The side panels in your drawing are far enough apart that they can create a notch in response at a frequency low enough to be problematic for a sub. Hornresp will not indicate this because it only calculates in one dimension - the length dimension. Since your ENTIRE enclosure is framed between these two parallel side panels the notch might be a big problem. Dividing the enclosure into two OR using solid bracing down a significant portion of the line length would help break this up. Danley talks about the parallel wall notch issue in the Labhorn notes in this quote:
That's why I said "your amp seems too small unless you are more concerned with battery life than spl potential."
It was indicated that battery life was plenty long even with one battery but more output was desired.
I didn't realize that, but it may be a significant contributor to highly regarded brand names costing double or triple or more for the same amount of power. I'll take the power over the birth sheets, but I'm generally cheap that way.
You can't put a larger fuse in than the electronics can handle or you will blow up the amp or cause a fire. The class of amplification and fuse rating are a good indication of how much the amp can put out. Not as good as 3rd party testing but way better than trusting the specs of a car audio manufacturer. JL and Alpine don't lie nearly as much as some companies but I don't trust any of them. For that matter I don't trust ANY amp manufacturers (even pro amp manufacturers) to tell the truth in specs and I don't trust ANY driver manufacturer to tell the truth on the power handling or xmax specs. There are way too many ways to cheat on these specs, no consistent industry wide test protocol, and everyone wants to have the highest numbers. Then when the marketing dept gets involved in writing up the spec sheet there's no integrity either. If there is a CEA compliance test (I have no idea what that actually is) and it's applied consistently to all brands and models and it's done by a reputable 3rd party that's a good step in the right direction, but I don't want to pay double for the product that was tested.
The $160 Planet Audio amp I linked should put out at least as much power (if not more) than the JL and it's almost 10x less money.
PA is always run at the ragged edge of destruction. No exceptions. If it's not running hot you brought too much gear. Considering the limited amount of available space in that truck and the stated desire for more output I don't think having an oversized amp is ever going to really be a problem.
I agree, but if the system is unplugged from the charging system at least 50 percent of the time I wouldn't put any money at all into the wiring or alternator. I'd put the money into batteries and amps. If it's not currently enough 3db more would certainly help. A more efficient box would help a lot too, but if the new box can't be significantly larger than the current one it can't possible be a whole lot more efficient no matter what type of enclosure it is. Ported is the king of enclosure size to spl output ratio as long as the ports are big enough and the power supply is adequate.
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Only if something goes wrong with the amp, and who says those elcheapo manufacturers are concerned about whether or not it blows up? In any case, 100A flowing into a cheap amp because of a failure is the same as 100A flowing into an expensive one for the same reason, isn't it? Both would pop the fuse 🙂.
The CEA 2006 rating is a well-established one that's been around from since, well 2006. There's quite a bit of info available for it on the 'net. I wouldn't purchase a car audio amp that does not claim compliancy with the spec. I'd be afraid of those blowing up and causing fires, LOL.
I hate hearing PA systems run that way - they sound like crap. In any case, the SPL level requirement would also depend on what the audience wants, right? So the question here is does the originator of this thread really feel that the intended audience feels the need for ~3dB increased output so much that a significant investment is required in amps, batteries, upgrading the electrical system and redoing the box is required in order to fill that need.
Thanks for the banter, this is informative even if I have thought about a lot of these things (power requirements vs spl output vs efficiency vs size of enclosure). It's nice to hear you all talking about it in similar ways that I have conceived.
I usually run things just under the ragged edge- if I hear any distortion I turn it down.. Good sound and headroom is my jam. I usually like to have as much [headroom] as possible. Granted, with these outdoor style PA systems it can be hard to keep it there... but I seem to manage.
Audio source is usually a DJ mixer console w/ integrated audio interface (Traktor Kontrol) or a mixboard.
The alternator is rated for 140a continuous, 105a continuous at idle. Only connected to the system while charging. During use, I have the motor off because I figure carbon monoxide doesn't smell very good to the people trying to get their dance on.
I was very surprised when the audio lasted for 2 hours on one 35ah battery, quite impressed actually. I was expecting to have to turn the car on for extra juice, but I didn't have to. I imagine it was pretty darn close, but then the party moved and I recharged en route to the next stop. Whew. Now adding a second battery, I should easily have 4hrs at full cut.
Even though the JL mono amp pulls 1200w continuous (I read a review where they tested actual output and it came in above the rated), as we all know music is transient. Given where I like to run it at about 75% (100% being balls to the wall destructo mode), I can't imagine it is pulling more than 300-400W continuous during bass heavy songs. I have read many places that continuous music program power is as low as 25% of the peak power during a normal EDM song. I have confirmed this by being attentive to my watt meters / amp hour catalogers attached to the various battery powered systems I have built over the years, and it is mostly EDM music we are playing through them.
Given that I was running the system on a 35Ah battery for 2 hours, that would mean at most it was pulling ~18A continuous or 216W- and that includes the tops as well. Considering how loud it was, that is a shocking calculation. The system is already very efficient and does sound great. The dance party was among the healthiest I have ever seen from a system I built.
Looking over the speakers, it appeared that they were getting close to their 12.5mm xmax during punchy hits- which is where I like to have it. I don't want to push these babes too hard.. they cost me a pretty penny and blowing one is not worth it to me for the extra 3db. Even though guy is right, 3db can always help!! We will always want more, as long as there is headroom for it.
So, I am quite happy with the power going to the speakers. I could get another identical HD1200 or replace with something that pushes more, but I like knowing that my subs are safe and that they will be reliable even when one of my friends goes a little too far with the bass levels in Traktor. That will happen 😉 Actual power source is not an issue, the deep cycles I run are high drain electric vehicle type batteries meant to output several kW of power. The other added benefit of having batteries right next to the amp, is that the resistance is very low due to short power cables. I am sure the 1ft 4ga is more than enough.
Additionally, I have installed a 150a alternator noise filter, so if needed I can hook directly up to a generator or alternator and not have to worry about noisy power supplies. I also ran a ground loop isolator before the input to the active crossover. This system is crystal clear no noise whatsoever even when the car is on 🙂 Very happy about that!
Anyway back to the tapped horn stuff. At 1200W is there a chance a high aspect ratio mouth won't be much of an issue? Because even if it comes out very similar to the vented box in terms of SPL, I will still have that directivity which is beyond wonderful for the kinds of situations I am using this for. I like to stand behind the speaker and have a quiet conversation (where I like to be), meanwhile people are getting their chests pounded with sweet nectar waves of bass on the other side. It's a thrill to see.
I am just confused how to start simming this in hornresp, if I were to do two drivers next to each other with a high aspect ratio mouth. Just to see. What kind of flare? What horn length do I need for 35-40hz? What kind of compression can I get away with these drivers? Gah so much I am unsure about.
Thank you for the help everyone, it is much appreciated.
I usually run things just under the ragged edge- if I hear any distortion I turn it down.. Good sound and headroom is my jam. I usually like to have as much [headroom] as possible. Granted, with these outdoor style PA systems it can be hard to keep it there... but I seem to manage.
Audio source is usually a DJ mixer console w/ integrated audio interface (Traktor Kontrol) or a mixboard.
The alternator is rated for 140a continuous, 105a continuous at idle. Only connected to the system while charging. During use, I have the motor off because I figure carbon monoxide doesn't smell very good to the people trying to get their dance on.
I was very surprised when the audio lasted for 2 hours on one 35ah battery, quite impressed actually. I was expecting to have to turn the car on for extra juice, but I didn't have to. I imagine it was pretty darn close, but then the party moved and I recharged en route to the next stop. Whew. Now adding a second battery, I should easily have 4hrs at full cut.
Even though the JL mono amp pulls 1200w continuous (I read a review where they tested actual output and it came in above the rated), as we all know music is transient. Given where I like to run it at about 75% (100% being balls to the wall destructo mode), I can't imagine it is pulling more than 300-400W continuous during bass heavy songs. I have read many places that continuous music program power is as low as 25% of the peak power during a normal EDM song. I have confirmed this by being attentive to my watt meters / amp hour catalogers attached to the various battery powered systems I have built over the years, and it is mostly EDM music we are playing through them.
Given that I was running the system on a 35Ah battery for 2 hours, that would mean at most it was pulling ~18A continuous or 216W- and that includes the tops as well. Considering how loud it was, that is a shocking calculation. The system is already very efficient and does sound great. The dance party was among the healthiest I have ever seen from a system I built.
Looking over the speakers, it appeared that they were getting close to their 12.5mm xmax during punchy hits- which is where I like to have it. I don't want to push these babes too hard.. they cost me a pretty penny and blowing one is not worth it to me for the extra 3db. Even though guy is right, 3db can always help!! We will always want more, as long as there is headroom for it.
So, I am quite happy with the power going to the speakers. I could get another identical HD1200 or replace with something that pushes more, but I like knowing that my subs are safe and that they will be reliable even when one of my friends goes a little too far with the bass levels in Traktor. That will happen 😉 Actual power source is not an issue, the deep cycles I run are high drain electric vehicle type batteries meant to output several kW of power. The other added benefit of having batteries right next to the amp, is that the resistance is very low due to short power cables. I am sure the 1ft 4ga is more than enough.
Additionally, I have installed a 150a alternator noise filter, so if needed I can hook directly up to a generator or alternator and not have to worry about noisy power supplies. I also ran a ground loop isolator before the input to the active crossover. This system is crystal clear no noise whatsoever even when the car is on 🙂 Very happy about that!
Anyway back to the tapped horn stuff. At 1200W is there a chance a high aspect ratio mouth won't be much of an issue? Because even if it comes out very similar to the vented box in terms of SPL, I will still have that directivity which is beyond wonderful for the kinds of situations I am using this for. I like to stand behind the speaker and have a quiet conversation (where I like to be), meanwhile people are getting their chests pounded with sweet nectar waves of bass on the other side. It's a thrill to see.
I am just confused how to start simming this in hornresp, if I were to do two drivers next to each other with a high aspect ratio mouth. Just to see. What kind of flare? What horn length do I need for 35-40hz? What kind of compression can I get away with these drivers? Gah so much I am unsure about.
Thank you for the help everyone, it is much appreciated.
ALL manufacturers are extremely concerned with product failure, they have to warranty the product. If it's proven that the output transistors melt before the manufacturer specified fuse that company will not be in business for long. There are safety issues and legal liability too, and I'm guessing some type of government regulations for safe design including fuse ratings.
Anyway, are Planet Audio or Hifonics considered el cheapo? I haven't been paying attention but I always thought Hifonics was regarded positively (and I think they are CEA rated too) and while Planet Audio is considered a bit cheap but the experience I had with mine was great. A quick search says the same board in my PA amp was used in the following amps:
. Lanzar Heritage HTG2600D
. Power Acoustik A2400dB
. Soundstream Picasso 1.1400D
. SPL Z1X-2400D
. Kole Audio QX1-2400D
. Planet Audio BB1250.1
- and probably a few more too
Most of those manufacturers I've never heard of but Soundstream is fairly high class while Lanzar is not.
So that's at least 6 different companies using the same board and specifying power ratings all over the map. For example Planet Audio rates the amp at 1250 watts max and Power Acoustik rates it at 3600 watts max but according to the manuals for these amps they are both rated for 120 amp fuses. Even Soundstream rated this amp with higher max watts than Planet Audio.
So this is only one example but it implies that a lot of manufacturers are not actually designing their own products (other than the case and packaging) and the distinction between cheap and expensive brands is at least sometimes based largely on the name on the box, not the electronics inside the box.
A quick search indicates that CEA compliance costs money so there's a pretty good reason for manufacturers not to do it. Also there seem to be loopholes, the rating only has to apply for a 4 ohm load, for any other impedance you don't have to be CEA compliant in the power rating. And worst of all it seems there is no 3rd party verification, so a manufacturer could pay for their CEA rating and STILL put whatever number they like on the spec sheet. (A lot of this info came from forums so it may or may not be accurate - I don't have time to read the official documents right now.)
"The crowd seemed to love it, but I will always want more."
There are two ways to get more.
1. More power
2. More efficiency through sub enclosure design
I see quite a bit of potential in option 1. Not so much in option 2 unless F3 is raised or box size is increased significantly. Making a tapped horn the same size or slightly larger than the current box isn't going to gain much.
Depends on the media. Sine143 has shown that bass music can be equally as demanding as a pure sine wave when low passed. In compressed bass heavy music with a constant bass line the dynamics are in the higher frequencies, the sub can see almost pure sine waves for the duration of the track. Search his user name with the keyword Hunter for a track analysis.
This is surprising. A sim of your box should show nowhere near xmax with 1200 watts if it's properly high passed.
Anyway, if you are happy with the power supply and amp side that's enough said about that.
As I mentioned aspect ratio doesn't cause problems, boundary layer friction does. The only way to reduce the effect is to reduce the surface area of any boundaries inside the horn path (including bracing). If you have enough solid bracing inside the horn to break up the side to side resonance caused by the parallel side walls the boundary layer area is going to be ~ the same regardless of the aspect ratio.
But if you are worried about it, just change your drawn design so the drivers are vertical instead of horizontal, that will make the mouth much more square and also eliminate the parallel wall resonance issue. The aspect ratio at the throat will still be the same though.
The required horn length depends on the desired tuning and the flare shape. More flare (bigger mouth) will require a longer length to achieve the same tuning. The sim I showed was just a bit more than 3 meters, I think.
Generally you don't want much more than 3:1 compression ratio (SD:S2).
S4 has to be at least big enough to fit the driver with a bit of extra space (at least an inch) if it vents through the back.
Your plans will be up to 25 percent larger than your sim since you need extra space for wood and extra space for the corners.
S2 and S4 are not very flexible in a small tapped horn. There is a minimum size they can be but within your desired dimensions they can't be much larger than the minimum size dictated by compression ratio (S2) and driver fit (S4).
So the only thing left to play with is S1 (which won't change much no matter what you do with it), S3, S5 and the individual segment lengths. But even these inputs are limited by final enclosure size.
I think you are going to find that whatever you do your final sim is going to be pretty close to what I showed you in the first place due to the previously mentioned limitations.
When you have a sim you like the final step is to print out the horn data (cross sectional area vs length chart), decide if you want to use centerline or advanced centerline folding method, and start drawing the horn path into your desired dimensions. A handy trick to keep things square is to remember that any PAR segment that is folded over onto itself (either fully or partially) will create a perfect rectangle (if it's only partially folded onto itself the folded part will be perfectly rectangular). If you are extremely lucky it will fit exactly into your desired dimensions. If it doesn't (it won't) you need to try a different layout (different fold) and/or change the sim to match your drawing. At some point you will come to a compromise that's good enough. The whole folding process is a lot easier if you don't have to fit it into predetermined dimensions but in this case you have no choice.
It's also very important to make sure that if you use more than one flare rate that your simulated S3 is located in a bend in the plans so the horn can physically change it's flare rate when it's supposed to. Most people screw this up.
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Thanks so much for the help. I found a tutorial on this website and it's starting to make some sense.
Here is my first go after 15-20mins of tweaking and not looking at that first sim you posted. Also I am modelling in 4pi space and 2 drivers @ 49V which is where I have my JL amps calibrated.
Response is bumbly, and reaches xmax at 35hz 😛
Well, it's a start I suppose. But I have a feeling I'm about to get schooled for posting this, lol.
Here is my first go after 15-20mins of tweaking and not looking at that first sim you posted. Also I am modelling in 4pi space and 2 drivers @ 49V which is where I have my JL amps calibrated.
Response is bumbly, and reaches xmax at 35hz 😛
Well, it's a start I suppose. But I have a feeling I'm about to get schooled for posting this, lol.
Forgot to mention, I just did some tape measuring and to make things a bit more interesting I'm going to up my size requirement to 39w x 25h x 36d. That should allow some more breathing room! 575L external volume.
Input params...
EDIT: And the current vented box model for comparison, sorry I have not done actual measurements yet
EDIT: And the current vented box model for comparison, sorry I have not done actual measurements yet
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Stick to 2 pi, even on the truck the sub is close enough to the ground to be considered 2 pi over at least most of it's bandwidth. (Close enough = 1/4 wavelength or less at any given frequency.)
Don't worry about exceeding xmax below tuning, that's what the high pass filter is for. You are using a high pass filter at or right below tuning, aren't you?
Keep your throat side tap as close as possible to S1 unless you want the response to drop like a rock at 100 hz. (If that's what you want though there's nothing wrong with that.)
You want to switch to PAR segments, you don't want CON since you are using flat sheet material with parallel side walls.
Unless you want a bunch of different flare rates you can change S2 and/or S3 from manual to auto.
Other than that you are on the right track.
There are a bunch of tutorials but now that you've got the basics playing with the sliders will probably teach you everything you need to know a lot faster. Very soon this will start to seem a lot less like work and a lot more like fun.
Don't worry about exceeding xmax below tuning, that's what the high pass filter is for. You are using a high pass filter at or right below tuning, aren't you?
Keep your throat side tap as close as possible to S1 unless you want the response to drop like a rock at 100 hz. (If that's what you want though there's nothing wrong with that.)
You want to switch to PAR segments, you don't want CON since you are using flat sheet material with parallel side walls.
Unless you want a bunch of different flare rates you can change S2 and/or S3 from manual to auto.
Other than that you are on the right track.
There are a bunch of tutorials but now that you've got the basics playing with the sliders will probably teach you everything you need to know a lot faster. Very soon this will start to seem a lot less like work and a lot more like fun.
Yes I have a BW 48 @ 20hz on the minidsp currently, but obvi I can change it to 30 or whatever I need 🙂
It's already a lot more fun now that I feel like I am getting somewhere. Thanks for the help and for bearing with me! I really appreciate the input a whole heck of a lot
It's already a lot more fun now that I feel like I am getting somewhere. Thanks for the help and for bearing with me! I really appreciate the input a whole heck of a lot
Ahhh Auto! That makes this a whole lot easier.
Alright I've switched to parabolic for everything, can you explain what you mean by keeping S1 close to the throat side tap? L12?
Thanks again, this is a huge help. Feels much more within reach now.
Alright I've switched to parabolic for everything, can you explain what you mean by keeping S1 close to the throat side tap? L12?
Thanks again, this is a huge help. Feels much more within reach now.
WOOF!!
Alright, I'm officially having fun. But feel free to rain on my parade, I am known to become way too excited
Alright, I'm officially having fun. But feel free to rain on my parade, I am known to become way too excited
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A very rough mockup.
S areas are actual as well as L12 & L34. Horn path 333cm, so some room to work with.
Also not taking material thickness into account
Box dims in inches are roughly 36w x 22h x 36d with a couple inches added for material thx (I upped my max box dims to 39wx25hx36d)
S areas are actual as well as L12 & L34. Horn path 333cm, so some room to work with.
Also not taking material thickness into account
Box dims in inches are roughly 36w x 22h x 36d with a couple inches added for material thx (I upped my max box dims to 39wx25hx36d)
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