Best Shallow Sub

Amen to that!!

 

Bottom line on how not to blow a subwoofer.
1. Don't put it in the wrong enclosure. This can be checked using subbox pro. Free software online and easy to use for basic calculations.
2. Don't put too much power on it. This can be measured with a multimeter.
3. Don't send a clipped signal to it. This can be measured with an Oscilloscope.
4. Use the correct crossover.
5. Stay within the subwoofer limits, Don't bottom out the sub by not having a subsonic filter on the low end.

Example. I can have the sub in the wrong enclosure, one that is built way too big for the sub, tuned low, large port area and the sub sound just fine on say 300 watts and the sub will play for years on this setup. But put, say 350 watts on it , will smoke it pretty quick.

 

Two 12" 400w pioneer subs compared to the factory sub!

 

That looks so big and gaudy compared to that cute little thumper....

 

But seriously though where did you find the box at?

 

I’m more curious what the box specs are. Gross internal volume, material thickness, internal bracing, etc.

 

This is totally speculative, but I remember seeing a similar looking box on Tech12Volts at some point and just double checked. Looks to be the same except for the niche near the bottom:

 

I second that!

 

That’s where I got it!

 

The only spec I know is that it fits behind the seats!

and it sounds really good!

 

It is invisible!

 

Is it sealed or ported?

 

I can appreciate that, but it’s a very subjective response. Knowing the specs would help other members decide if the box would be a good fit for their choice of subs, as well as their music preference.

 

I just talked to James tech12volts a couple days ago and I think he said for 12's it was about 1 cube per sub so i would assume total is about 2 cubes air space but I don't remember if he said mounting depth. He did say the dd shallows should fit though if that helps any.

 

Sorry, I honestly don’t remember the details. When I came across this box that fit, I matched the specs to the pioneer subs that I was looking at and everything lined up. Wish I could be less subjective. If you’re considering this box reach out to James he was very helpful and responsive.

https://tech12volts.com/shop/ols/products/14to21-tundra-cm-subwoofer-enclosure

 

M.B. Enclosures dropped a new vid discussing/further testing the Wavepro's: WavTech thinPRO 12 …142db@37hz, 140db@35hz and More w/ MB Commentary and Understanding !!

The main thing that caught my attention is him saying the subs don't play low very well. On paper they should given their relatively low Fs and very high xmax. Saw in the comments he plans on testing one rather than two in the hopes it'll perform better on the low end. I'm curious if it's a case of the manufacturer specs being over-inflated as his box volume seemed to be on point. I was getting pretty excited about these until he dropped this video. For punch I think they probably have the most output currently, but for frequency response they're not looking to be a unicorn just yet.

 

Why would you not be excited? You wont be competing, hardly any music has substantial 20hz bass because its just not "picked up" like he said. If its doing 140db @31hz with 1k watts, Id be thrilled.

Dont focus too much on loudness (db's), you want clean sounding...you wont be competing with these shallow mounts

 

Yeah I'm not focused on loudness at all, my focus is the best SQ sub money can buy. His testing hit 140 dB at 35 Hz and it sounds like they're super good in the higher end frequencies but not so good on the low end, which is typical of shallow subs. I've been messing around with modeling in WinISD but maybe there's someone more experienced that could take a crack at it as I'm curious how the thinPRO12 frequency response curves look on paper compared to the other "top" shallow SQ subs like the Illusion Audio C12/Audiomobile Evo 2410/JL 13TW5v2-2 etc.

 

I agree. Though, typically they list low end response as an f3, meaning I like response down to mid-20’s in a car.

Also, chasing SPL has a lot to do with the vehicle as an enclosure and less to do with the subwoofer and it’s enclosure. SPL competitions are about a single note, not the average SPL of the spectrum of notes from 20hz-20khz. You can tune a sun in a box in a car (another box) to interfere constructively at a specific resonance and boost SPL by 10db+ compared to the average response.

So I’m just reiterating what Eddie said about clean sound throughout the spectrum.

It’s still cool that a slim sun can hit 143, though.

 

If ya wanna go all in get the gaetley audio sub box with the 4 alpha 8's you WONT be disappointed.

 

Yeah I mean on paper and in testing it looks like the thinPRO 12 is the new king of the hill as far as SPL goes for a shallow sub, but I couldn't care less about how loud my subs get anymore. I know that higher output at a given frequency probably means higher output across the board, I don't see an F3 listed for the Wavtech, but using the JL 13Tw5 and 12TW3 as examples, they have an F3 of 41.18 Hz and 37.99 Hz respectively for their spec sealed boxes, and the highly lauded Illusion Audio C12 has an F3 of 42 Hz in .75 ft^3. There are so many numbers/parameters it makes my head spin lol.

 

yep...and very rarely does one sub check all the boxes for what you need

 

In my last setup I had my 8w7 in a spec sealed box and it was really good except for super deep notes. I built an in-console box that housed a 6w3 and the combo of those two sounded really good for most songs, but I’ve been craving that real low end lately. If I could get a shallow sub with good low end output I’d totally consider adding a front sub and band passing it to play the higher sub notes.

 

Haha. Ya, definitely a lot to chew on. F3/F10 etc (-3db, -10 db) are shown by modeling in-box response using the TS parameters, and verified with an impedance sweep with the driver in the enclosure. You should be able to find a predicted f3 with a good modeling program and accurate parameters.

Just as a general reference, a vented enclosure is typically going to have a lower f3 than a sealed enclosure; the rolloff is more gradual in a sealed enclosure so the f10 is often lower in a sealed enclosire.

And then there’s in-cab response which can alter the response drastically, but typically adds 10-20db starting around 60hz and peaking around 20 hz.

All that gobbligook is what makes it fun, frustrating, confusing, and fulfilling all at the same time. If you take a quality sub and put it in a poorly designed box, it can sound like garbage. Compare that to a mediocre driver in a well designed box and it will far outshine that high dollar driver.

I enjoy ‘what’s best’ threads as long as we don’t take them too seriously, mostly because best is about finding the best compromises that meet your needs. I enjoy exploring those compromises and finding strengths.

But I’ll get off my soap box now

 

It's more of a rule of thumb for the subs and sub amp
....
Every sub has an efficiency rated output (db/1-watt@1meter) and of all types of speakers, subs have the lowest "db/w" roughly 82-85 They have the hardest job of moving air so we give them a break. Where as with woofers, mids, and tweets generally have higher efficiency output, roughly 88-93bd. Their jobe is much easier and take far less power to produce the same perceived output level in the clean, loud, and clear arena. Basically it of course takes more power to push a sub so you need a good matching sub amp.
But amplifiers aren't always honest about their rated output too, (a certain % of distortion @ a given frequency, @ a % of power out= clean, undistorted + musical. But full output power is usually riddled with distortion. So, to get the sub and amp to "match up right" - plan on using "80%" of an amps undistorted power by adding 20% to the top of the subs rated RMS. = 80/20.
400w sub gets a 500w amp. (Technically 480watts)

We used this rule of thumb "80/20" to calculate sub amp and sub choice in our system designs @ RCT in Boston. It was simply explained to me by Rich Inferrera as "Subs just need more power to play right."
So I listened to the Godfather himself, and the advice has never let me down.

 

I started modeling the Wavtech in WinISD and it was seemingly going good but then for some reason the SPL graph wasn’t working. Putting in the T\S and other available parameters into WinISD was pretty easy/straightforward I’ve just gotta sit down and mess around with it for a bit to get the hang of it. I think you can specify the box volume in it otherwise it calculates off an anechoic chamber. Definitely looking forward to learning the more advanced parts of audio it as I feel like I’ve got a decent grasp of the beginner stuff.

I’ve always just gone off rms ratings and matched those up as close as possible but I’ve heard the 80/20 thing from a few people now and I’m sure so long as you’ve got a good amp and well set gains having the headroom is probably the “right” way to set up a system.

 

Ah, I think I see where you are going. No need for a rule of thumb as you can easily calculate power requirements and SPL output.

The SPL rating of a driver is often called "efficiency" but it's kind of a misnomer as it's a relative efficiency, not a calculated efficiency. It's better termed "sensitivity" as it's how sensitive a driver is to make noise when powered. There is a parameter for calculated efficiency in watts that is rarely offered by a manufacturer; it is power out/power in. For traditional cone/coil transducers, that number is usually less than 1% and the rest is turned in to heat (which is why voice coils have to be built to handle so much heat and are rated in watts). The power of the cone and magnet puts out is extremely inefficient compared to the power you put in to it. Think about a wall charger that takes 120v ac power and converts it to 5v dc power to charge your phone. If you measured the power input vs the power output, you would see that Power In > Power Out as it takes energy to convert the voltage. This excess energy is converted in to heat and is why your phone charger wall wart gets warm when it's charging your phone. Your energy conversion will ALWAYS be less than 100% else you will be creating energy from less energy which is tantamount to perpetual motion...

So how, then can you have a speaker driver with over 100 db efficiency? Look up pro woofers in the 18" range (woofers, not subwoofers) and you will find them to be 106+ db efficient! It's because there term we define as "efficiency" in a speakers specs isn't actually efficiency.

The SPL "efficiency" of a driver is simply how loud - in decibels (db) - a speaker will play as measured by a microphone placed a specific distance away, while being fed a specific amount of power. It is usually standardized to 1 watt measured at 1 meter, or 2.83V/1M as a way to compare drivers with different impedances (remember those random equations from high school physics or electrons classes Power = Voltage^2 / Resistance? The resistance of the speaker will change the power (watts) and voltage so we keep voltage steady to maintain a consistent measurement). Feed that speaker 2.83V and measure how loud it is with a (calibrated) microphone placed 1 meter away. If you run a sweep from 20hz to 20khz, you can get a frequency response curve by measuring the SPL level at different frequencies. But the SPL rating of a driver is typically an average response in the passband of the driver (subwoofers are going to omit frequencies above 150hz, 300 hz, 1000 hz depending on the drivers usage; tweeters typically omit response below 1000 hz or so, and so on). That's how the SPL parameter is derived.

So if you are using the SPL rating a driver as a rule of thumb of how much you can overpower a speaker, you are actually conflating two different things: the power handling capacity of a driver (both it's thermal limits and mechanical limits) has virtually nothing to do with SPL rating of the driver.

However... the maximum SPL of a driver CAN be derived from the SPL rating and the power handling rating of a driver. That's actually quite simple and can be done mathematically. Then you can compare it to other speakers in the system to determine how much power you need to create the overall volume (maximum SPL) of the system.

Bare with me and I'll give you an example, but as a preface, the Sound Pressure Level scale is a logarithmic scale with base 3: ever 3 db is a doubling in output or loudness. It requires double the power or double surface area of a cone (assuming the cone is in it's pistonic range where it's not losing efficiency to suspension losses or loss in magnetic flux density) to achieve 3db more SPL. The way our hearing works, our loudness perception is around 10 db to sound like it's doubled in volume, and 1 db is the smallest perceivable change (for most). Our ears are also less sensitive to highs and lows and most sensitive in the vocal range (being that we communicate vocally to one another, that is a good thing).

That said, lets say you are upgrading your system with two speakers in the front and a subwoofer in the back (for simplicity sake we'll ignore the rear speakers). You chose a set of front components rated at 92 db "efficiency" and a subwoofer rated at 86 db "efficiency". You have a 64 watt amplifier for the front speakers (ya, I know it's a somewhat random number, but for illustrative purposes, it's perfect) and you want to know how much power you need for your sub - both the power handling capacity of the driver and how much power you need to supply with an amplifier. Let's assume the front speakers can handle ALL of the 64 watts from the amplifier, and that they are either receiving a total of 64 watts split between the pair and that their SPL rating is for a pair of speakers and not a single driver.

Starting with 92 db @1 watt, lets iteratively double the power and increase the SPL by 3 db until we reach 64 watts.

1 watt = 92 db
2 watts = 95 db
4 watts = 98 db
8 watts = 101 db
16 watts = 104 db
32 watts = 107 db
64 watts = 110 db

So just to match the front speakers output at full tilt, we need a subwoofer capable of reaching 110 db. Let's do the same iterative process but starting at 86 db. We could also do some maths using powers and subtract our reference SPL from our max SPL - 110 - 86 db = 24 db - but the iterative process is simpler and more illustrative.

1 watt = 86 db
2 watts = 89 db
4 watts = 92 db
8 watts = 95 db
16 watts = 98 db
32 watts = 101 db
64 watts = 104 db
128 watts = 107 db
256 watts = 110 db

So in this example, we need four times the power for out subwoofer to match the output of our speakers.

However, there are two other things going on that we ought to account for: the listener is typically sitting closer to the front speakers than they are to the subwoofer. The same rules of power and SPL apply to distance (since our SPL rating was derived from power @ distance): 2 meters requires double power, 4 meters requires doubling again, 8 meters doubling again, and so on. So lets just assume the listener is sitting twice as far from the sub as he is from the main speakers. So either the SPL is halved (minus 3db) or the power is doubled to match the drivers, due to distance.

The second thing is that perceive bass notes to be a lower volume than midrange. 6db between a woofer and tweeter (the woofer playing 6db louder) is often considered full baffle step to have the outputs perceived as matching. Theaters that use THX spec, for example, require a subwoofer to play 10 db louder than the main speakers. So let's add 9 more db (6 db more than the main speakers) in order to have a completely fulfilling experience with bass. Staring where we left off above but with the output halved since we are sitting twice as far away from the subwoofer:

256 watts = 107 db
512 watts = 110 db
1024 watts = 113 db
2048 watts = 116 db

Yikes. Thats a lot of juice. You could solve the problem one of a couple of ways: decrease the power seen by the main speakers, or add multiple subwoofers (double the cone are = double the output), select a large subwoofer (again, more cone area, but incremental), or select a driver with a higher db rating.

The last option is good for many things with the except of low bass. High SPL "efficiency" drivers typically have light cones and require large boxes, but also have a higher Fs or natural resonant frequency. Subwoofers that play low bass in a small box have heavy cones for a low Fs, and don't get much boost from the box, so they are typically lower in SPL "efficiency".

So we are left to find a good compromise between low bass, small space, required power, and Maximum SPL. Also, I neglected to factor in cabin gain (which can also be calculated or just account for in WinISD) as I mentioned in an earlier post. This actually makes the bass more efficient in the relatively small space of an automobile, so the first iterative process we used to match the subwoofer output is typically close enough. Your subwoofer usually requires 4x the power of your main speakers to match output and max SPL.

Sorry for the novel, but I wanted you to know there a simple maths to explain rules of the thumb, and hopefully illustrate the confusion that often happens looking at specs.

 

You've go me curious about the Wavtech driver; I'll try to look up the specs and model in WinISD to see what it looks like.

 

I know the talk has been subs but just curious if anyone has played with the newer stinger amps and if they are worth it or being a budget amp are they mediocre? Looking at their 2000 watt sub amp

 

Alright, @Snert I modeled up the WavTech ThinPro12 in WinISD and found some interesting results.. Warning: this is pic heavy...

First, I modeled both a sealed and vented enclosure and went with what WinISD recommended to meet a maximally flat amplitude response for sealed (.707 Qtc) and a Q4 Chebyechev (kinda the same thing) vented. WinISD kicked out 1.125 cuFt sealed and 2.47 cuft vented. Normally I fiddle with the optimal box sizes and reduce them 10-20% which doesn't affect the response much but gives you smaller enclosure. I'm just going to leave them be for now.

F3 sealed = 42 hz
F3 vented = 21 hz




Lets run 750 watts to each one and see what happens to the rear port air velocity and cone excursion.

Even with a 4" x 24" port, this thin runs way past the 17 m/s recommended port velocity (you can stretch this out a bit, but this isn't great; you will hear it FOR SURE). So it looks a Sealed box is the best bet (or moving the vent tuning up a bit, but that would make a somewhat lumpy response on the bottom end).




Cone excursion was surprising fine above 20 hz for the vented box, but I decided to throw a 20 hz HIGH pass LR4 on both drivers just for some bottom end protection. Cone excursion is VERY low for 750 watts RMS. Enough that we can try pushing more power to the driver until we reach cone excursion.





Both setups will take around 1700 RMS before breaching Xmax. Not shabby!





But lets knock power back down to 750 RMS and check SPL and Amplifier Apparent Power. Remember how we mentioned that a subwoofer doesn't always see the same power at every frequency, and that just because you have an amp of X amount of power, your subwoofer wont' see all of that power? That's what the Amplifier Apparent Power shows. And what do you know - below 50 hz, the subwoofer and box aren't seeing full power but are keeping up with output.





Lets apply an 80hz low pass filter, also LR4 and see what happens. That should keep us frying the VC playing the upper bass, and I would low pass a subwoofer anyways. Lets check Amplifier Apparent Load again. We are still seeing less than 500 watts. Hmm. Note: at this point, I've started to ignore the vented enclosure, so ignore the green line).






I've got one more filter to apply: Parametric EQ of 3 db at 30 hz to boost the bottom end of the sealed box. Note that parametric EQ requires more power; 3db is going to double the power at 30 hz so if we are pushing 750 watts, it actually needs 1500 watts to take advantage of that boost.

Checking cone excursion and running up wattage until it peaks, we can push 900 watts before hitting the 20mm xmax. With boost, thats 1800 watts at 30 hz. Nice.






End Result: a 12" subwoofer in a box a little over 1 cu ft, sealed, 1800 RMS with 3db boost at 30 hz, and you get an F3 around 32 hz, F6 in the 20's, and over 110db (in vehicle will add 10-20db). Dang. I'd be more than happy with that setup. I'm impressed with that driver!