Music Vs Ht Subwoofer Design

[KeithL]

WHAT MAKES UP A GOOD MUSIC SUBWOOFER VS HT SUBWOOFER DESIGN? (LOOKING AT WinISD)

F3?
GROUP DELAY?
IMPEDANCE?
IMPEDANCE PHASE?

:confused:

[billfitzmaurice]

WHAT MAKES UP A GOOD MUSIC SUBWOOFER VS HT SUBWOOFER DESIGN? (LOOKING AT WinISD)

F3?
GROUP DELAY?
IMPEDANCE?
IMPEDANCE PHASE?

:confused: Music only needs to go to 35-40 Hz, HT a half to full octave lower. That makes HT subs a lot larger to deliver the same output, see Hoffman's Iron Law.
And stop yelling, it's Sunday morning for crissake. :cool:

[KeithL]

And stop yelling, it's Sunday morning for crissake. :cool:[/QUOTE]

WHO'S YELLING?

[brianpowers27]

HT loves to slam the system with 20-30hz sounds momentarily while Music typically posesses more sustained content centered above 40hz.

Do with this as you please. I always recommend that you go for as much displacement as your room and WAF can handle.

[KeithL]

HT loves to slam the system with 20-30hz sounds momentarily while Music typically posesses more sustained content centered above 40hz.

Do with this as you please. I always recommend that you go for as much displacement as your room and WAF can handle.

SHOULD I LOOK FOR FLAT TO 40HZ, F3 40HZ, 1-2 DB BOOST AT 40HZ? ANY RECOMMENDATIONS FOR GROUP DELAY?

I WISH I KNEW HOW TO COPY WinISD GRAPHS TO THIS THREAD.

[johnnyrichards]

Keith, first turn the cap lock key off. All caps is considered "yelling" in netiqutte, and people find it bothersome.

Secondly, there is no difference between HT and "music only" subs, except for people's perception of what constitutes either. Ideally, any subwoofer should be flat to 15 hz with no distortion over it's operating range and capable of more than 110 db output.

However, this is usually unobtainable without $$$.

IMHO, it should work with any content you throw at it. You can call it a HT sub or a music sub or whatever you want to, but it isn't a subwoofer if it only goes to 40 Hz to cover "music".

[KeithL]

Keith, first turn the cap lock key off. All caps is considered "yelling" in netiqutte, and people find it bothersome.

Secondly, there is no difference between HT and "music only" subs, except for people's perception of what constitutes either. Ideally, any subwoofer should be flat to 15 hz with no distortion over it's operating range and capable of more than 110 db output.

However, this is usually unobtainable without $$$.

IMHO, it should work with any content you throw at it. You can call it a HT sub or a music sub or whatever you want to, but it isn't a subwoofer if it only goes to 40 Hz to cover "music".


My Bad!

I am looking at a design with:
4.5cuft
Tuned to 26hz

F3: 25.5
F10: 19.6
Group delay:23.739ms @ 23.78hz

Max Spl
20hz - 100.282
30hz - 114.45
40hz - 113.97
50hz - 115.37

Thoughts, Comments?

What are you using in your system??

[philiparcario]

Keith if you are going to have a 2.1 system. I would say buy this driver

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-444


put it in a sealed box of 2 cu ft stuff it with 1 to 2 pounds of poly fil


with this sub and call it a day

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-804

[gc1]

WHAT MAKES UP A GOOD MUSIC SUBWOOFER VS HT SUBWOOFER DESIGN? (LOOKING AT WinISD)

F3?
GROUP DELAY?
IMPEDANCE?
IMPEDANCE PHASE?

:confused:

Tight musical tone V. "boom 'n' roar"... detail V. output... Transients V. excursion... very different.
I like solid output to 20hz with both... but HT needs more output.

[billfitzmaurice]

Group delay:23.739ms @ 23.78hz
Group delay below 100 Hz or so is inaudible, so ignore it. What you need for a sub is dependent on your program material and how loud you want it.

[brianpowers27]

Keith,

This will be much easier for us if you can tell us what your goals are. We need to know what you are using it for, a little about the room, the way you like to listen (loud) and what you are listening to

[KeithL]

I already own this driver and wanted to see if it was worthwhile to build a home subwoofer, as it is a unit designed for a car.

At this point it will be used in basement with about 1200sq ft. Somtimes playing music while I workout, sometimes just sitting down and listening.

I am just curious what I should be looking for spec wise in a design, F3, F10, delay...

Thanks

[brianpowers27]

When you spec'd things above, did the program take into account the xmax of the driver? If so, that looks like a fine setup to me. GO for it. If you are unsure, build it with cheap OSB. If you like it, build a nicer box.

[KeithL]

Yes.

It is a Digital Designs' 3012 12" DVC. Rated at 400rms, 11mm xmax, 89.4dB.

Would I be better off to lower the tuning to increase 20hz output while decreasing output from 80hz and down?

If you are running WinISD, here are the specs:
qes .42
qms 4.01
qts .38
fs 25hz
vas 147 liters
re 2.7

[Phil_RC_1]

WHAT MAKES UP A GOOD MUSIC SUBWOOFER VS HT SUBWOOFER DESIGN? (LOOKING AT WinISD)

F3?
GROUP DELAY?
IMPEDANCE?
IMPEDANCE PHASE?

:confused:

My opinion is that a "music" sub will simply have a flat response in the lower octaves. A music sub install has to consider room gain and will tend to have more attention paid to low distortion and accuracy. Since room gain is in the equation, they are often sealed enclosures that when coupled with room gain have a flat response. Since little music detail is usually in the lower octaves, a huge x-max isn't required, unless you're a closet DJ (LOL) and play it ear bleeding loud. In a word "accuracy" best describes a music sub.

HT subs tend to have more output capability and even a peaky or rising response output below 30 or 40 hz. Also a hefty X-max to accommodate higher SPL in the lower octaves for room shaking explosions. A peaky response this low will tend not to effect music that much but gives the WOW factor in movie explosions and special effects.

IMHO, If you design a sub in a box modeling program that is flat down to 25hz without considering room gain, you'll pretty-much have a HT sub.

With all that said, I agree that a reasonable compromise can be had to meet both criteria with minimal impact to either.

[KeithL]

What determines a good transient response?

Driver?
Cabinet?
Room?

Thanks for all your responses.

[philiparcario]

In the case of subs. the right driver in the right box. room can alter transient response . sealed subs tend to be more articulate you will hear separate bass notes not muddy notes.

A ported sub can sound very good. I had a pair of 12inch focal subs in large ported cabinets. great bass to 30hz clear sounds and played loudly. the dayton rss390hf in an IB will be close to perfect in the range of 20hz to 60hz. it starts sounding wrong around 90hz.

[KeithL]

Are there any drivers on the market that will give a flat response or even f3 @ 20hz?
And still have good transient response?

[brianpowers27]

Design guidelines... If you have a way to eq the sub (Behringer feedback destroyer). Shoot for something that has a naturally low f3. The benefit fo finding a system with a low f3 is that it is generally more efficient this way. Use the eq to tune it flat.

Side note: Very few designers actually obtain a f3 of 20hz without eq.

[philiparcario]

Are there any drivers on the market that will give a flat response or even f3 @ 20hz?
And still have good transient response?

dayton rss390hf-4 will as an IB

[KeithL]

OK, So Iwas playing with the eq feature on WinISD and cha-ching.

3.5 cuft tuned to 20hz

With the following eq settings and 140 watts(max excursion of driver @ 28.36hz) I get the following results:

20hz 108.056dB
30hz 109.215 dB
40hz 108.893 dB
50hz 110.322 dB
60hz 110.524 dB

Not to shabby on paper

[Dirk]

OK, So Iwas playing with the eq feature on WinISD and cha-ching.

3.5 cuft tuned to 20hz

With the following eq settings and 140 watts(max excursion of driver @ 28.36hz) I get the following results:

20hz 108.056dB
30hz 109.215 dB
40hz 108.893 dB
50hz 110.322 dB
60hz 110.524 dB

Not to shabby on paper

How much gain did you apply? The EQ feature in WinISD is *slightly* confusing. If, for example, you specify a +3dB bump at 30hz and then model the system at 100W input power, in actuality you'll be putting 200W into the driver at 30hz. Not really an issue, just a caveat. Model the box without the EQ and adjust the power until the excursion graphs overlap at the boosted frequency. That will tell you how much real-world power you'll need.

Also, if you're adding EQ, you should also be modeling the lowpass as applied by your receiver. It can change the picture, as well.

[Deward Hastings]

With the following eq settings and 140 watts(max excursion of driver @ 28.36hz) I get the following results:

20hz 108.056dB
30hz 109.215 dB
40hz 108.893 dB
50hz 110.322 dB
60hz 110.524 dBWell . . . that lets you know that the (theoretical) frequency response is reasonably flat (no telling what it will look like in the room, though) . . . BUT . . . if maximum driver excursion is reached at 28 Hz then you probably won't get 108dB at 20 but a broken woofer instead. And (depending on the box allignment) if excursion just keeps increasing below 20 Hz then there are a couple of movie sound tracks that you'd best avoid . . .

What you have to remember is that that the power input that exceeds maximum excursion at *any* frequency is your effective power limit at *all* frequencies, because that LF "effect" *will* come along and bottom your driver otherwise. That's why ported and IB allignments need a high-pass filter, to protect the driver from VLF transients, but of course then you lose bass response, just as you would with a sealed box . . .

[brianpowers27]

Keep in mind that excursion goes through the roof right below the tuning frequency. If 28.36 is above the tuning frequency... it may only take about 1/5th power to reach the limit at 15hz.

In this case... you are good,even with the highpass. You could throw more power at this sub and it would take it. My guess is that a 300 watt amp would be a good match. With a boosted amp as shown below, there is a peak around 30hz. This is probably not desirable. You could make the box smaller or tune the box lower...

With the amp pegged you will reach 106.8db at the peak. (30hz)

Edit... Out of curiosity I modeled this.
Note: one graph is the transfer function. One graph is the woofer with hp and one without.

[KeithL]

At this point I own the driver, I own the PE 250w sub amp plate and would be looking at the Reckhorn or Elemental Designs sub xover/eq units to equalize and further control high and low pass. I guess all that is left is to build and experiment with tuning and equalization.