Mainly asking for recommendations for a driver/TH design combo:
Looking for a sub to build that can do 40-80hz (so narrow bandwidth) with high sensitivity (close to 100db would be nice), that "can get loud" with "not too many watts" for "an evening" on 12V battery power - outdoor over sand.
Is that too vague?
I've read through most of the SS15/THAM15 etc. and most compact horns threads, and with so much info and banter, one only gets more confused just as you think you got it. So I might as well just ask. What should I build (for an existing design)?
I know I can only pick 2 out of extension/size/output, so here are my Priorities:
1. F3 of 40-80Hz (Music include EDM, tops high passed at 70Hz)
2. close to 100db sensitivity (so it can get loud with "not too many" watts and the battery can last "an evening"
3. high value, budget driver (will only be used a handful of times a year)
4. Not too hard to build (i've done a few HT horns)
Saving graces:
1. Dont need wide bandwidth.
2. Size and weight not *as* big of a priority. I'll just fix it on a hitch tray at the back of a SUV.
3. No need high power handling (I only have a few watts to throw at it, so budget drivers with "lower" xmax is ok?)
3. Class D efficient amps
Maybe this amp, front 2 channels for tops, bridge the rear 2 channel for the sub:
Dual DA704L 600W 4-Channel Digital Low Profile Series Class D Car
Is this realistic?
Is below 50hz considered pointless outdoor with limited power?
Looking for a sub to build that can do 40-80hz (so narrow bandwidth) with high sensitivity (close to 100db would be nice), that "can get loud" with "not too many watts" for "an evening" on 12V battery power - outdoor over sand.
Is that too vague?
I've read through most of the SS15/THAM15 etc. and most compact horns threads, and with so much info and banter, one only gets more confused just as you think you got it. So I might as well just ask. What should I build (for an existing design)?
I know I can only pick 2 out of extension/size/output, so here are my Priorities:
1. F3 of 40-80Hz (Music include EDM, tops high passed at 70Hz)
2. close to 100db sensitivity (so it can get loud with "not too many" watts and the battery can last "an evening"
3. high value, budget driver (will only be used a handful of times a year)
4. Not too hard to build (i've done a few HT horns)
Saving graces:
1. Dont need wide bandwidth.
2. Size and weight not *as* big of a priority. I'll just fix it on a hitch tray at the back of a SUV.
3. No need high power handling (I only have a few watts to throw at it, so budget drivers with "lower" xmax is ok?)
3. Class D efficient amps
Maybe this amp, front 2 channels for tops, bridge the rear 2 channel for the sub:
Dual DA704L 600W 4-Channel Digital Low Profile Series Class D Car
Is this realistic?
Is below 50hz considered pointless outdoor with limited power?
The SS15 seems like the most optimized design, but I worry that I regret not having that extra 10Hz at the bottom.
A pair of brian's poc#3 with the Dayton Audio PA310-8 can go slightly lower, and cheaper drivers. But would a pair stack up to one SS15 in output per watt? I think realistically I should be shooting for only about 100W. So maybe the low xmax is not a problem?
THAM15 can go lower too, and almost as sensitive, whats the best budget driver for this design right now?
I'm not doing concert levels here for an off grid outdoor system. Just enough for 30 people to bounce around in the middle of nowhere and be able to stop once in a while to appreciate how nice a 12v system can sound!
A pair of brian's poc#3 with the Dayton Audio PA310-8 can go slightly lower, and cheaper drivers. But would a pair stack up to one SS15 in output per watt? I think realistically I should be shooting for only about 100W. So maybe the low xmax is not a problem?
THAM15 can go lower too, and almost as sensitive, whats the best budget driver for this design right now?
I'm not doing concert levels here for an off grid outdoor system. Just enough for 30 people to bounce around in the middle of nowhere and be able to stop once in a while to appreciate how nice a 12v system can sound!
Probably a bandpass 6th order will achieve all targets in a good size. The hard part of this design is to proper tune the box, maybe would be better to measure the driver before to build the cab if you choose this type of cab.
There are some modern bandpass cabs like the superplanar and roar that can achieve the target too but you need to certify that you won't need wider band in a future because they have a big dip in the upper frequencies.
Thank you for pointing out the new trends in DIY subs! Now I have a lot more reading to do. Any specific designs/drive combination I should look at?
regards
Bern
The SS15 is large & loud. It may roll off earlier but will outperform an equivalent reflex cabinet with the same driver at all frequencies and be up to 103dB efficient.
In its original 12mm form with glue joints it is an easy build but not suitable for high power
If you can live with the size a pair of these will surprise you.
What mid tops would you use crossing over at 70hz?
Most mid top designs would struggle to get that low and keep up with a SS15
In its original 12mm form with glue joints it is an easy build but not suitable for high power
If you can live with the size a pair of these will surprise you.
What mid tops would you use crossing over at 70hz?
Most mid top designs would struggle to get that low and keep up with a SS15
I like how you say low power, and 12v, then whip out a 600w amp. If you will have a full vehicle there, then you have some serious power available. The thing to worry about might be that you are using a cranking battery, not a deep cycle battery if you are using a non modified vehicle. 100db should be pretty easy to hit when you do not have an enclosure size constraint. any random 90db sub with 10-20 watts is there already. ( I modelled my current dayton dvc 15 in a 80l sealed box in 2pi space and it is 100db at 40hz with 20w) With a decent sized class D car amp, you can do whatever you want really lol.
I don't think that amp is bridgeable. You might want to confirm that.
If you're using car audio amplifiers, I suggest planning around a 2 ohm load, and going with a class D amp for the subs that can provide as much power into that load as you can afford.
With a two ohm load, you're then looking at a 4x8 ohm subwoofer arrangement, or a 2x4 ohm subwoofer arrangement. The choice of which arrangement to go with would probably come down to budget and how much space you're willing to give up. For example, for $300 in drivers alone, you could go with two boxes each holding two of the Dayton Audio PA380 drivers in a 40 Hz vented alignment, and each box should get pretty close to 100dB @ 40 Hz sensitivity. Offset TLs with the same drivers in larger boxes should increase the overall sensitivity a little.
The POC3s are tuned to around 39~40 Hz and the SS15 is tuned much higher, and uses a larger driver. I suspect it's going to take more than two POC3s to keep up with an SS15, at least to its cutoff point
FWIW, the POC3 along with my Blastoramas is my regular "beach system" (when I do the beach), and I cater to a group of friends (who number 30 or smaller). The combination sounds good (ok, really good), but is really not loud enough to start a dance party, the main limitation being the output around 50 Hz, where the PA310 is running out of excursion. A 40~42 Hz double 15 based on the PA380 might do the job though. The PA310 is not really that happy with such low tuning anyway - it's much happier in the 48 Hz offset TL in which it now resides, awaiting the next beach party test.
I think he's looking for 100dB sensitivity, not peak SPL.
My two Alpine Type R 12" drivers in my car audio system will happily hit 100 dB, but unless I keep the car running, it's not going to keep up that average SPL level for long.
Simple 40 Hz offset TL with the PA380. One will have a sensitivity of 95dB/2.83V/1M, so two will put you over that 100dB sensitivity target. Each can take just over 200W (40V) before exceeding linear excursion limit, and will likely comfortably take 350W each above 40 Hz without anyone noticing anything. And the amp will be seeing a 4 ohm load. The big "vent" will ensure little or no vent compression effects up to the peak SPL capability of the box (particle velocity will peak at 10 m/s @ 40 Hz with 40V drive).
Net volume for both will be less than one SS15.
Build 4, drive them off an amp that can do 1.2kW into 2 ohms, and I think that should be more than enough for your 30-person beach party..
Net volume for both will be less than one SS15.
Build 4, drive them off an amp that can do 1.2kW into 2 ohms, and I think that should be more than enough for your 30-person beach party..
Attachments
My bad, I totally misread sensitivity vs sustained output. yeah 100db sensitivity is more interesting as a problem for sure. Multiple drivers as already suggested would be where I looked first. A TH from 40-80 might be really big.. whatever you do, please post some sims / what you end up doing.
Doubling cabinets and drivers would add +3dB sensitivity, for 98dB, 2 dB shy of 100dB sensitivity ;^).
Sim looks very good, and amazingly compact!
Blamus said "I'll just fix it on a hitch tray at the back of a SUV."
One Keystone with an Eminence 4015LF (or perhaps a PA380) would do what a pair would for sensitivity 40-80 Hz, but might be a stretch for a hitch tray at 33% larger than the pair of your offset TL.
Bottom line- a 3dB increase in sensitivity (one watt one meter) doubles the time you can play off the battery without recharging.
When Peukert's law is factored in for lead acid batteries, the time may increase by as much as four times!
A sheet of plywood made into "barn doors" around the subs can add 3 dB sensitivity to any (smallish) design, and can be fit in the back of an SUV.
Don't leave home without it!
Cheers,
Art
+3dB for the doubling of drivers, +3dB for the halving of impedance.
So sensitivity goes from 95dB/2.83V/1M (8 ohms) to 101dB/2.83V/1M (4 ohms)
Four of these boxes should get to 107dB/2.83V/1M (2 ohms).
Those car audio amps do better with low impedances.
The boxes should be easy to build (basically shelf-vented boxes with one extra internal panel). If I was building them, I'd add an extra brace across the top, like I did for my POC6 build (not visible in any of the build pics unfortunately, but the top panel should be braced if it's going to be that large, unless you like to see anything placed on top the box being vibrated off).
Thanks. It could probably do with a bit of tweaking (I'm tempted to enlarge the vent and go with a 42 Hz tuning to reduce any vent compression effects @Fb even further and up the output capability a little), but it does look nice on paper.
And the total cost in drivers for four of those boxes is less than $300.
A 4x8 sheet of ply can be cut into two to make "barn doors" for a stack of two of these subs. I suspect though that they will also act as pretty good sails if the beach is windy
Note: I did not use the "Lossy Le" option for this sim. With that enabled, a hump does develop in the response, but it's been my experience that Le for the PA310 measures lower than published, and it may be the same for the PA380.
Brian,
Car amps may be capable of low impedance operation, but are no more efficient at low impedance, which the OP wants to maximize by using sensitive speakers.
According to the international IEC standard 60268-5, a loudspeaker’s sensitivity is determined by measuring its output when driven by a band limited pink noise signal with a Vrms equal to the square root of the loudspeaker’s rated impedance and referencing this SPL to a distance of 1 meter.
Since sensitivity is dB SPL output per watt, though a four ohm load will draw twice the power (wattage) at a given voltage, it does not make it 3 dB more sensitive. So many are playing games with the definition, that folks are forgetting the "game rules".
Two boxes will use half the power of one for a given SPL, four boxes one quarter.
And the extra frontal area of two or four will increase sensitivity by a bit more compared to one.
Art
This discussion has been had here several times before, Art.
Sensitivity is measured dB/2.83V/1M, not in Watts.
It's EFFICIENCY that is measured in dB/1Watt/1M
Sensitivity and Efficiency are only equal when the impedance of the device is 8 ohms (2.83V into 8 ohms = 1 Watt) .
For more info - Loudspeaker Sensitivity & Impedance Explained | Audioholics
WOW! cool!
I like the PA380 - definitely a driver that fits my budget.
Brian:
I see that you have "moved on" from TH POCs onto these offset TL's etc. Do you find this new alignment more suitable for your aims? significantly smaller for a little sensitivity loss? I assume others have simmed it in other horns? Does it do well in the SS/THAM/keystone etc? Would it gain sufficient sensitivity in one of those horns to justify the larger size? like Art pointed out, every 3db doubles my play time which is very significant! I do not plan to hook this up to a running car. I'm hoping a normal deep cycle battery (500WH?) will do.
I think I just found somewhere in the TH18 and keystone threads that the PA380 sims well, if xmax limited - which is "ok" for my anemic power? The "600W amp" I showed was just the cheapest 4 channel bridgable D amp I found with crossovers. In reality I'd hope to use less watts than its full power (doubt it makes full power anyway, likely a 75W per channel RMS), but the $25 2.1 TPA3116 with 50wx2 + 100W is also very attractive choice
I will definitely add the barn doors!
I like the PA380 - definitely a driver that fits my budget.
Brian:
I see that you have "moved on" from TH POCs onto these offset TL's etc. Do you find this new alignment more suitable for your aims? significantly smaller for a little sensitivity loss? I assume others have simmed it in other horns? Does it do well in the SS/THAM/keystone etc? Would it gain sufficient sensitivity in one of those horns to justify the larger size? like Art pointed out, every 3db doubles my play time which is very significant! I do not plan to hook this up to a running car. I'm hoping a normal deep cycle battery (500WH?) will do.
I think I just found somewhere in the TH18 and keystone threads that the PA380 sims well, if xmax limited - which is "ok" for my anemic power? The "600W amp" I showed was just the cheapest 4 channel bridgable D amp I found with crossovers. In reality I'd hope to use less watts than its full power (doubt it makes full power anyway, likely a 75W per channel RMS), but the $25 2.1 TPA3116 with 50wx2 + 100W is also very attractive choice
I will definitely add the barn doors!
Last time I checked, efficiency was a percentage.
Anyway, for a 30 people beach party I would go with one or two SS15's, loaded with the Dayton and perhaps that amplifier mentioned. That would be plenty in my experience, without the need for confusing terms and definitions.
Best regards Johan
Throwing in 2c - I built a pair of SS15 loaded with 12" (design slightly tweaked to suit) and ran them off battery powered amps. The result was phenomenal, absolutely pounding upper bass and super efficient... I did miss the lower end, but that's the compromise you have to make.
Which makes me wonder, on a beach with heaps of noise from waves, will the low end be missed?
Which makes me wonder, on a beach with heaps of noise from waves, will the low end be missed?
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