New RT-12d sub on order

[Tom Adams]

No......I don't have one on order (dammit), but was curious if anyone here has plunked down money for one.

BTW - can someone from Klipsch feed us some trivia about what or how on the designation for the new subs? I mean, I'm sure the "12" stands for the driver size, but what in the sam hills does "RT" stand for?

Tom

[Jay481985]

im debating on it with the little savings I still have after the rf-83 I have.... MSRP is 1999 or same as the rsw-15. The RSW-15 street was around 1400-1500.... hmmm or I can finish the subwoofer that I wanted to build but would be around 1800 dollars. (Adire is very sloowww and promises so it might be time to step up to TC sounds QVC 3000)

[DrWho]

Well RS-12 was already taken and T comes after S, so RT would be the next naming scheme?

And then I'm pretty sure the d stands for the digital room correction.

[DrWho]

im debating on it with the little savings I still have after the rf-83 I have.... MSRP is 1999 or same as the rsw-15. The RSW-15 street was around 1400-1500.... hmmm or I can finish the subwoofer that I wanted to build but would be around 1800 dollars. (Adire is very sloowww and promises so it might be time to step up to TC sounds QVC 3000)

A pair of QVC 3000 15's in a sealed 8 cubic box would annihilate the RSW and Tumult. If you wanna go smaller, then use a pair of the QVC 3000 12's in a 4 cubic box and sacrifice 4dB of output. Depending on your room gain, you're looking at 132dB with nearly flat extension below 10Hz...now to find an amp capable of 1500W into an 8 ohm load...

But even after all that, the room correction dsp seems like a very attractive option. You can have all the horsepower in the world, but that's not gonna do much when the sub is working against itself in a crappy room.

[darkside]

Mebe Rt stands for "Reference triangle" possibly? I dunno......

[Jay481985]

im debating on it with the little savings I still have after the rf-83 I have.... MSRP is 1999 or same as the rsw-15. The RSW-15 street was around 1400-1500.... hmmm or I can finish the subwoofer that I wanted to build but would be around 1800 dollars. (Adire is very sloowww and promises so it might be time to step up to TC sounds QVC 3000)

A pair of QVC 3000 15's in a sealed 8 cubic box would annihilate the RSW and Tumult. If you wanna go smaller, then use a pair of the QVC 3000 12's in a 4 cubic box and sacrifice 4dB of output. Depending on your room gain, you're looking at 132dB with nearly flat extension below 10Hz...now to find an amp capable of 1500W into an 8 ohm load...

But even after all that, the room correction dsp seems like a very attractive option. You can have all the horsepower in the world, but that's not gonna do much when the sub is working against itself in a crappy room.

I need to go but I rather have dual 15 in a 4 cubic foot since I already made the box in a sealed and have EQ I forget right now but its f3 would be at 19 hertz and linear from then and up. Also I do not need 132 db I rather have the 114 db at 20 hertz and would be aroudn 120 db with roomgain etc hence it matches my rf-83 output... No need to be twice as loud...

[Jay481985]

Tom Adams I must apologize for hijacking your thread but DrWho here is what I plan to do. The yellow is a 4.2 cubic feet sealed dual TC sounds QVC 3000 15 inch uneq.

The red is a 8 cubic feet sealed same un Eq

The Blue is a 4.2 cubic feet sealed dual TC sounds QVC 3000 15 inch with:

Linkswitz Transform (F0=50 Q0=.57 fp = 20.00. Qp= .68

Highpass Linkwitz-Reiley, N-4, fc=11 Hertz

Note the blue f3 is at 18 hertz

the red f3 is 60 hertz

the yellow f3 55 hertz

The blue Qtc will be probably .7

red will be .460 which is really boring and not punchy,

yellow is .568 which is still under the .707 range which is a nice balance.

[Jay481985]

SPL

the eq 4.2 cubic feet box is 114.5 decibals at 20 hertz which is nice for 270 watts.....

the unEQ 4.2 cubic feet box is 110.5 db @ 20 hertz but at 2000 watts or max rms watts of the speaker

the unEQ 8 cubic feet box is 112.5 db@20 hertz but still at 2000 rms watts

the thing is since the eq box is eq it cannot exceed 270 watts without overexcursion so i trade max volume for depth but the nice thing is it is as deep from one watt to 270 watts as its flat even at low volumes

[Jay481985]

Now I doubt drwho that you will be un eqing the 8 cubic feet box but since you did not say how I did not bother to try and figure out what you did. 8 cubic feet is also a huge box....... And I rather not have huge box and uncessary db. I am not doing decibal drag racing nor do I car for 130 db. I rather have my subwoofer match my RF-83 which are rated 120 decibals. Since the rt-12d is rated at 121 decibals at 30 hertz I wonder if one is enough for down low 20 hertz to match the rf-83. And I know you will bring up percieved bass and you need to run the system hot to hear the 20 hertz but I am not willing to double the enclosure size. And don't remind me of the 16 cubic foot sub I talked about before [] what was all what I wish and not reality.

This picture is the xmax at full volume or limited before max excursion happens. Note the EQ subwoofer the blue line is just touching xmax at 270 watts.....

also the 8 cubic foot box would need a highpass filter as I guess the size of the box is to big to act as a spring to keep the excursion in check. But again I don't know what you were going to do.

[DrWho]

You need to take into account room gain and voice coil temp (1 degree

Farenheit for every watt is fairly accurate). And don't forget to add

6dB to convert from half-space to eigth-space.

Do you actually have a

linkwitz riley filter available to your disposal?

You also need to take into account the apparent amplifier load...with that much EQ you are pushing 3000 watts. sizzle sizzle.

The 8 cubic foot box doesn't require any EQ, will do 130dB with 1200W

and will have an F3 between 20Hz and 10Hz depending on how lossy your

room gain is. It will definetly have output below 10Hz regardless and

has very good nonlinear behavior.

The 4 cubic foot box requies EQ at 47Hz which ideally would vary with

output level (-4dB at full output ruins the response at low levels). It

can handle 2000W of power and is thermally limited. It peaks at 132dB,

but rolls off faster below 35Hz (~2dB disadvantage). It has very

dramatic nonlinear behavior.

Ultimately I would choose the cabinet size based on the room gain of the room the sub will go into.

[DrWho]

If you absolutely must have 4 cubic feet, then I'd recommend two 12" drivers, or if you wanna go cheaper then a single 15" driver.

Dual 12's will do 127dB (1400W) with the same frequency response and linearity of the 15's in the 8 cubic foot cabinet (which makes sense, same motor strength, ~half the surface area, half the cabinet size).

I would choose dual drivers over a single driver to minimize cabinet vibration and the walking sub syndrome. The dual drivers should be mounted on opposite sides of the cabinet and have threaded rod running between them to provide even better mechanical damping. I've even seen people throwing vented PVC inbetween the magnet structures as well.

Ya, sorry for the hijack...this should definetly be in a thread of its own.

[Jay481985]

You need to take into account room gain and voice coil temp (1 degree

Farenheit for every watt is fairly accurate). And don't forget to add

6dB to convert from half-space to eigth-space.

I know hence the 114.5 db at 20 hertz goes to around 120 db at 20 hertz matching the rf-83

Do you actually have a

linkwitz riley filter available to your disposal?

it can be built, can it not?

You also need to take into account the apparent amplifier load...with that much EQ you are pushing 3000 watts. sizzle sizzle.

The subs can take it. the crown I am eyeing seems like it can handle up to 2400 watts

The 8 cubic foot box doesn't require any EQ, will do 130dB with 1200W

and will have an F3 between 20Hz and 10Hz depending on how lossy your

room gain is. It will definetly have output below 10Hz regardless and

has very good nonlinear behavior.

please show me your winisd model with an f3 between 20 and 10 hz for a sealed system. Again I do not need 130 db........

The 4 cubic foot box requies EQ at 47Hz which ideally would vary with

output level (-4dB at full output ruins the response at low levels). It

can handle 2000W of power and is thermally limited. It peaks at 132dB,

but rolls off faster below 35Hz (~2dB disadvantage). It has very

dramatic nonlinear behavior.

Thermally limited at 2000 watts rms for one hour. Kyle from tcsounds said to get the max amount of db you can feed your tc qvc 3000 1500 watts for a short time as many car audio people do but again no need for 130 db.

Ultimately I would choose the cabinet size based on the room gain of the room the sub will go into.

well since the room will change quite often from college every year new dorm to home etc that is not happening.

[Jay481985]

If you absolutely must have 4 cubic feet, then I'd recommend two 12" drivers, or if you wanna go cheaper then a single 15" driver.

Dual 12's will do 127dB (1400W) with the same frequency response and linearity of the 15's in the 8 cubic foot cabinet (which makes sense, same motor strength, ~half the surface area, half the cabinet size).

I would choose dual drivers over a single driver to minimize cabinet vibration and the walking sub syndrome. The dual drivers should be mounted on opposite sides of the cabinet and have threaded rod running between them to provide even better mechanical damping. I've even seen people throwing vented PVC inbetween the magnet structures as well.

Ya, sorry for the hijack...this should definetly be in a thread of its own.

Yeah ummm hmmm should we start a new thread??? And the dual driver for me is a must as you said with the canceling and mechnical damping.

and with the pvc are you talking about the sub, "The Beast" which used it on the passive radiators because the wood was bending to use as a brace"

[DrWho]

Blue = dual 15, 8 cubic feet

Green = dual 15, 4 cubic feet

Purple = dual 12, 4 cubic feet

The lines up top are an indication of peak SPL and have some nonlinearities thrown in. And room gain was assumed to start at 35Hz. The only plot implementing any EQ is the green plot with -4dB at 47Hz, 12dB/octave (Q = .707). The lines near the bottom show the more linear behavior at normal listening levels and each setup is running with 10W of input.

[DrWho]

Btw, the previous plots were 1/2 space...add 6dB for 1/8 space.

Here is the transfer function plots to make the relative frequency

responses easier to see. Note how the resonse increases at the

impedance peak of the system...this is actually the result of power

compression (10dB swing, yikes!). By making the cabinet larger, you

lower the frequency of the impedance and thereby make the extra boost

beneficial, just gotta be careful of exceeding excursion.

Speaking of excursion, without any filtering it is controlled down to about

5Hz...well out of the region to be concerned about.

[Jay481985]

note I always believed that linkswitz was a EQing and hence could not understand how f3 at those low ranges were achieved

[Tom Adams]

Jay & DrWho.......thanks ever so much for completely and thoroughly hi-jacking this thread. Even after you guys acknowledged that you should start a new thread - you kept on.

Sheesh........you kids nowadays. [] [] []

Tom

[DrWho]

It's an indirect suggestion for your HT []

[Jay481985]

uhhhhh soooo Tom, did you ever get to do the DIY sub? how about a 4 cubic feet :-P

[Tom Adams]

At the risk of this reply sounding like a boo hoo story........

My purchases or DIY sub or just about anything else of the sort is pretty much on hold (along with my life) as long as this "marital issue" exists between my wife & I. [] [] [:'(]

Tom