You will just miss all the low notes. Completely missing. Classic rock and girls and guitars music might be ok with a 50 hz tuning but the genres you are interested in have a lot of notes lower than 50.
There are a couple of ways you can figure out what's going on here. To see it visually, download a program like Audacity, load up your favorite tracks and check the frequency response.
OR use a program to cut everything below 50 out of the track and listen to it. OR use an amp with a high pass filter and set it to 50 hz and listen to it outside. NOT inside or in a car, you have to do this outside or the cabin gain will add the bass back. What you will find is that it will go quite loud when set like that but the lack of lower notes might be maddening.
I can't live with less than flat response down to 27 hz or so, and there's a lot of stuff on pop radio that goes lower than that. I think "Royals" by Lorde has a 20 hz bassline, I only mention that because it was a popular recent radio song that you probably know. Especially when listening to rap/ hip hop / dub type of stuff it sounds really stupid when the low notes are missing. Like a really loud clock radio kind of.
Under the steering wheel (what you would call the firewall in a car), that isn't just a panel that comes right out? It looks like a speaker is mounted down there by the driver's feet. I'd be surprised if that was permanently blocked in and really surprised if it was structural.
When my brother redid the floor in his boat he had it stripped down to the fibreglass shell and all that stuff came right out, it was completely open to the nose. Those "firewall" panels came right out without cutting into anything.
Hornresp can sim things like that. It can't sim EXACTLY what you have there with the two little stubs but it can get pretty close, and you can redraw that into something it can sim, or just kinda ignore the little stubs and include them in the enclosure volume. Akabak can sim it as drawn but Akabak's learning curve is a bit steep.
As drawn, that really doesn't provide much protection from moisture.
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Note that one of the more popular TH designs here (the SS15) doesn't go much below 50 Hz
.There's also the question of defining exactly what's meant by a "50 Hz tuning". Fb=50 Hz? F3=50 Hz?
Given the volume he's working with (~4 cu.ft.) and the fact that a car amp is providing the power (so impedance should be 2~4 ohms), and that whatever is chosen for that goal should also feature some sort of weatherproofing as it's going in a boat, that does pose a challenge getting both loud AND low, unless one opts for some sort of active alignment to boost low frequencies (e.g. go for a 35 Hz Fb in a vented alignment, then "fix" the passband droop with EQ).
That picture one I got from the internet of my same model and year of boat, but not my boat, so I am not sure what is mounted in that "firewall" area in the picture. What I do know for certain is that is a fiberglass piece that is not removable on this boat. Not only that, there are multiple electronics modules for gauges and cruise control etc mounted behind there. Technically it could all be relocated and I could punch a big hole in there but I would rather not. And the space behind there is another under seat storage locker with an equally challenging shape to the one I am working with now.
Note that one of the more popular TH designs here (the SS15) doesn't go much below 50 Hz
There's also the question of defining exactly what's meant by a "50 Hz tuning". Fb=50 Hz? F3=50 Hz?
Yeah but the SS15 is pretty specifically PA oriented, and will almost always have either a 1 pi or 0.5 pi environment to help out. (Not that will shift fb lower than a couple hz but every bit counts.) I'm not sure exactly who is using SS15s and what music they are playing but I can tell you I'd demand my money back from any musical related event using "subs" like that.
OR find a bigger spot to put the sub. I'm still pretty sure the nose is the best spot, and I'm pretty sure the panels under the steering wheel will pop right out to access that area. I wouldn't really even consider any other options until that was completely ruled out as a possibility. No matter what you do, if the port size is big enough to avoid acoustic problems, it's going to get wet inside the box. It's a boat, wet happens.
Ok, that changes things. If it's not a removable piece it's probably structural and you shouldn't cut it at all. The gauges wouldn't have been any problem, they are well above the "firewall" panel, but if the panel is a part of the boat you can't mess with that.
Note that one of the more popular TH designs here (the SS15) doesn't go much below 50 Hz
There's also the question of defining exactly what's meant by a "50 Hz tuning". Fb=50 Hz? F3=50 Hz?
Given the volume he's working with (~4 cu.ft.) and the fact that a car amp is providing the power (so impedance should be 2~4 ohms), and that whatever is chosen for that goal should also feature some sort of weatherproofing as it's going in a boat, that does pose a challenge getting both loud AND low, unless one opts for some sort of active alignment to boost low frequencies (e.g. go for a 35 Hz Fb in a vented alignment, then "fix" the passband droop with EQ).
Thanks for the reply. I had initially thought f3 50Hz but I am not stuck on anything. I see so much conflicting information on this topic it is hard to know what to do. My past attempts in this boat included a JL audio 13 inch sub (13W6V2) with 1000 watts. Its F3 was probably 40hz and just not impressive at all.
I wonder what kind of freq response Outdoor DJ's aim for when designing a system for an outdoor dance or party. .
Give me a link to this design with the 12 hp1030 that you keep bringing up. And first be sure that it
will fit in his space requirements because otherwise it is a moot point.
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Something like that, but move the woofer up higher so the slot is maybe 3" for the port, calculate what you need for the slot in a simulator. I might have another slot independent for the woofers. I'd probably simulate in Unibox or similar to get the box size right, then use Hornresp or Akabak to see what the extra woofer slot does - Hornresp does not get the box size right for vented. I'd probably just line the woofer slot with acoustic foam to minimize cavity resonances and then look at the response in the boat and use digital EQ to fix it as needed. It is really just slot loaded vented with another slot in front of the woofers. While the woofer slot will resonate if it is damped and high enough out of your passband it should be okay.
Cheers!
Here's to an enjoyable summer for all.
Note: I only asked because I have spent some time in a particular Canadian province that has a lack of lake acres and a high per capita income.
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A heavy cone gets you extended bass in a relatively small box. He has 1KW the average power per woofer should be under 200W more likely even under 150W, I've not looked into how they do their testing but he is probably okay if he doesn't abuse the system. The Epic does have a metallic former that conducts to the aluminum cone. Not going to get into speculation, test one and show me the results. I'd worry more about this much power into a pair of Infinities, but at least they are cheap.
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Sounds like you doubt that it can be done so I did a quick 5 minute sim to make sure. This is dual 12 HP1030 slot chamber (not PPSL) loaded end to end in a 60 cm long chamber.
If you look really close there are a lot of things wrong with this that need a bit of tweaking. Port velocity is a bit high but probably not too bad with the required hpf in place and adding flares to the ends would clear that right up, lowering velocity to a mild breeze. It's a few liters too big (116 liters net) but the slot chamber is a lot bigger than it needs to be. It can't actually be folded as is because there's not enough room in the rear chamber for the drivers but that could be worked out pretty easily by morphing this into a reverse taper tl instead of a small ported box with a long port.
BUT as a quick 5 minute proof of concept it absolutely does work. It doesn't quite go up to 200 hz as the OP spec'ed but it isn't too far off and he probably doesn't need it to get up to 200 hz anyway. It does go a full 20 hz lower than he asked for, which is just a bonus. A simple 4th order high pass and 2nd order lowpass brings response right down to flat over a -3db bandwidth of 30 - 150 hz with no dsp or stuffing required (although a tiny bit of stuffing might not hurt) at 124 db within xmax with about 2200 watts.
This could be fixed right up into something that could be folded into the OP's desired dimensions but I'm not going to spend more than 5 minutes on this right now. As a quick proof of concept this absolutely would work, and there are other layouts and other alignments that could work with these drivers too.
In case it isn't clear this requires drivers with huge power handling, not high xmax, especially considering the music genres the OP is interested in. Infinities and Epics can only handle a fraction of this power. Tuning higher than this would only require a boatload more power to hit xmax, so higher tuning is not only not necessary, it's a bad idea, and Epics and Infinities are a terrible idea.
Personally I'd tune a bit lower than shown, and fwiw, Hornresp does a fine job with vented boxes, Pete.
An externally hosted image should be here but it was not working when we last tested it.
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Just one more quick note before bed...
Depending on how this is laid out there could be enough room for the drivers as it is, it is a 50 liter chamber. And reducing the cross sectional area of the slot not only reduces the overall box size by up to 10 liters, it greatly reduces the peak, allowing for a higher crossover point and a bit more high end bandwidth (but at the expense of a couple hz bandwidth on the low end). I wouldn't run a sub that high but OP mentioned a 200 hz high end so...
I wasn't sure if these things were immediately obvious especially for the people who don't know how to use Hornresp and want to attempt to sim this in Unibox so I thought I'd mention it, it is basically just a 6th order bandpass so the effect of specific tweaks should be pretty intuitive.
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HAha thanks for starting things off just a guy. I was posting exclusivly from my yesterday so I couldn't back my claims up (fact I'm still on my phone).
Bottom line, the 1030hp has very generous xmax of 12mm, a 4" coil with 1000w aes rating, insanely small VAS (less than half that of the epics, denoting it is *MUCH* better suited for limited space vented applications than the the epic 12), and a moderately high fs and efficiency.
Bottom line, the 1030hp has very generous xmax of 12mm, a 4" coil with 1000w aes rating, insanely small VAS (less than half that of the epics, denoting it is *MUCH* better suited for limited space vented applications than the the epic 12), and a moderately high fs and efficiency.
Yeah we've discussed this driver before and I'm glad you pointed it out to me. Since I've already worked with simulating it a bit I was pretty sure it would work within OP's dimensions and goals but just wanted to be sure with a quick proof of concept because Pete sounded doubtful. It is a pretty sweet little driver and it's great for small(er) boxes (even in huge horns, it requires less net volume than other similar drivers) but it is expensive. It costs as much as a pretty decent 18, but for jobs like this when you need a high(ish) tuning, loads of power handling and have to fit a couple of 12s in a really small space this driver is about as good as it's going to get.
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Out of interest I did throw a few of my techno tracks through a spectrum analyzer the other day, and I found out that what I thought was 30 hz actually is 40 hz.
Almost all of the tracks I tried were mixed with >40 hz in mind, some of them were down as much as 20 dB at 30 hz, some about 10 db and most of them somewhere between(altho more like 20 than 10.
This is the kind of techno I'm refering to(which I consider very low tuned), thought it might be out of interest when you choose how low you wish to go.
https://www.youtube.com/watch?v=Lsi7d5e7Xg0
Almost all of the tracks I tried were mixed with >40 hz in mind, some of them were down as much as 20 dB at 30 hz, some about 10 db and most of them somewhere between(altho more like 20 than 10.
This is the kind of techno I'm refering to(which I consider very low tuned), thought it might be out of interest when you choose how low you wish to go.
https://www.youtube.com/watch?v=Lsi7d5e7Xg0
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