Triple driver - sealed. Pros/cons, and is it too much for a newbie

[tb46]

Hi MedPed,

Here is a nice sealed box build using a 15" woofer:

Completed build, for inspiration..

Regards,

[bear]

Only for the point of discussion, I agree with Art on the LF localization.

And I said regarding a jet, not over the horizon, but above the horizon...

[MedPed]

Elberts build is truly inspiring - wow!

I think I am fairly restricted to about 6cu ft - about 160 liters. Given that, is there a point in going for larger drivers - 12 vs. 15 vs. 18". 18" will be more difficult from the aesthetic point of view if restricting overall size.

Say we have a few constants -
An amp with output such as the inuke 6000 DSP.
Limited to about 6cuft (about 150-175 liters).
Decided on dual subs - one driver each.
Desire for usable output at 18-20 Hz.

With those constant (constraints), driver recommendations? for 12, 15, or 18" sizes.
Pros cons for the lab12, the dayton 15HO, etc.
I like the fact the lab12 is about 89 db sensitive - unlike some of the others which can dip down to about 86 db - how significant are these published numbers?

Just for my knowledge - increasing from about 160 upto 189 or 220 litres (from 6 upto 7 or 8 cu.ft) - does that make a big difference? I want to get a sense of what I am compromising by trying to stay small. E.g for the Lab12 or similar driver.

[MedPed]

I was doing some measuring...
I can likely manage a pair of 27"x27"x27" sealed cabinets. That is about 11.3 cu.ft. external volume, and likely closer to 10 cu.ft. internally after bracing and driver displacement.

How would a sealed cab that size measure out with the Dayton Audio RSS460HO-4 18" Reference HO Subwoofer 4 ohm. Specs:
Power handling: 900 watts RMS/1,800 watts max • VCdia: 3" • Le: 2.10 • Impedance: 4 ohms • Re: 3.41 ohms • Frequency range: 20-500 Hz • Fs: 19.6 Hz • Sensitivity: 89.2 dB 1W/1m • Vas: 10.52 cu. ft. • Qms: 3.90 • Qes: 0.43 • Qts: 0.39 • Xmax: 12.75 mm • Dimensions: Overall diameter: 18.17", Cutout diameter: 16.69", Depth: 8.94"
http://www.daytonaudio.com/media/res...ec%20Sheet.pdf

Thanks Oliver, for your link to the post by mRgSr: New HT subwoofer. Dayton Ref 18".
He just finished his, and I would love to hear his results/measurements. His internal volume was about 8 cu.ft. Loved the cabinet.

If the consensus is that it might measure well, and he is happy with his, this might well be worth a shot.

Any thoughts?

Two of these drivers =$500. inuke6000DSP 450+tax. Throw in the cabinet costs, I am pushing probably close to $1200-1300. But for two 18" subs, I think it is safe to say, I will likely not be able to pick up anything retail for under $2000 that outperforms this pair, correct? Please agree with me.... please?

What other amp/dsp options should I be considering. I know there is probably a good used market out there, but due to my ignorance in the matter, I probably will not have clue what I am buying, and should likely stick to retail for something that you guys recommend. Also, it is worth getting the DSP amp, or separate amp and dsp units, eg. minidsp.

[bear]

One could say within reason that if you are going to use a DSP to EQ the sub, then the box almost doesn't matter, since the response will be that of the actual frequency response and "shape" (those being things like Bessel, Butterworth, C4 and things like that).

But still, one wants to run a simulator to see the "natural" response of the driver in a given volume box. With all the parameters inputted, you will see what your headroom and max SPL ends up being. Valuable information.

In general terms the higher the ratio of VAS : box volume, the higher the F3. The Q and the shape of the curve is also altered. So, good idea to put it into a simulator.

You might want to pick up a cheapo XP running windoze box to run for your audio hobby work?

_-_-bear

[MedPed]

Of chance do any of you have any experience with the Dayton Titanic III 15"?http://www.daytonaudio.com/media/res...ions-46168.pdf
On paper it seems to have similar output capabilites as the 18" reference:
http://www.daytonaudio.com/media/res...ec%20Sheet.pdf

How do they seem to compare? And how would they respond differently to cabinetry - changes in size?

[Moonfly]

Originally Posted by weltersys

I live in the hot dry desert of New Mexico.
Hot and dry result in the most HF air attenuation.

I can close my eyes and point to where a jet, 30,000 feet above was.

I say "was", as the jet will have traveled several miles in the time it takes to hear it.

Your "perfect example of how low rumble sounds are near impossible to locate" does not work for me, I can point directly to hot air balloons (which don't fly fast, and use burners that sound like a jet) or idling trucks far enough away to be barely visible.

Perhaps some people are less sensitive to localization down to a low frequency, I do find it interesting that many often say they don't "hear" but "feel" low frequencies.
I have no problem hearing undistorted LF below 20 Hz.
In fact, I have changed tables in restaurants because of air handling ducts resonating in the 15-25 Hz range.

My girlfriend, who hears to 20K, and about 50 dB better at 4K than I, won't notice such a sound unless I "point" it out.

Art

Thats fair enough. I have lived most of my life in a mild to cold climate where the countryside is all green valleys and rain more often than not. Perhaps that makes a difference.

Have you ever run a 15hz tone through a sub, and increased output till you can actually hear it measured with a spl meter. I can hear 20hz at fairly high levels, but 15hz and under is pretty nothing audible to me at all.

[Moonfly]

Originally Posted by MedPed

I was doing some measuring...
I can likely manage a pair of 27"x27"x27" sealed cabinets. That is about 11.3 cu.ft. external volume, and likely closer to 10 cu.ft. internally after bracing and driver displacement.

How would a sealed cab that size measure out with the Dayton Audio RSS460HO-4 18" Reference HO Subwoofer 4 ohm. Specs:
Power handling: 900 watts RMS/1,800 watts max • VCdia: 3" • Le: 2.10 • Impedance: 4 ohms • Re: 3.41 ohms • Frequency range: 20-500 Hz • Fs: 19.6 Hz • Sensitivity: 89.2 dB 1W/1m • Vas: 10.52 cu. ft. • Qms: 3.90 • Qes: 0.43 • Qts: 0.39 • Xmax: 12.75 mm • Dimensions: Overall diameter: 18.17", Cutout diameter: 16.69", Depth: 8.94"
http://www.daytonaudio.com/media/res...ec%20Sheet.pdf

Thanks Oliver, for your link to the post by mRgSr: New HT subwoofer. Dayton Ref 18".
He just finished his, and I would love to hear his results/measurements. His internal volume was about 8 cu.ft. Loved the cabinet.

If the consensus is that it might measure well, and he is happy with his, this might well be worth a shot.

Any thoughts?

Two of these drivers =$500. inuke6000DSP 450+tax. Throw in the cabinet costs, I am pushing probably close to $1200-1300. But for two 18" subs, I think it is safe to say, I will likely not be able to pick up anything retail for under $2000 that outperforms this pair, correct? Please agree with me.... please?

What other amp/dsp options should I be considering. I know there is probably a good used market out there, but due to my ignorance in the matter, I probably will not have clue what I am buying, and should likely stick to retail for something that you guys recommend. Also, it is worth getting the DSP amp, or separate amp and dsp units, eg. minidsp.

If you can do 175 litres, then I really would seriously consider the Fi Q18D2's. With 1500 watts power handling, and 28mm of xmax, they really do work well and sound very impressive. Hitting 20hz with these drivers in sealed units is a non issue. You can eq them to 10hz and get a fantastic sound from them, and system Q at 175 litres will be pretty close to the .707 ideal in room.

[MedPed]

175 litres are certainly more desirable than 270 for spouse acceptance factor!!
On review of the specs, it does seem that the Fi is more sensitive and with a lighter Mms than the Dayton. Wouldn't know if they are equally stiff.
The Qts is little lower on the Dayton.
The resonant frequency is pretty high on the Fi with a Fs 32.1 vs 19.6 on the Dayton.

I am trying to make sense of these numbers - so I don't over think it, what might these numbers mean to me and for cabinet construction and sound.

[tb46]

Hi MedPed,

In Post #62 you'll find Hornresp Input/multiple sub SPL screens, in Post #68 you have the displacement graph; these are close enough to describe mRgSr's project (I'm not going to spend the time calculating the exact internal volume, this is diy after all :-)). In his thread you'll also find my quick stab at a BR (vented/bass reflex) for this driver w/ the same external dimensions, Post #30: New HT subwoofer. Dayton Ref 18" .

I'll attach a SPL comparison for these two boxes. Gotta run......

Regards,

P.S.: I would consider two of those "serious" overkill. :-) Nice.