how low to go for music?

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As always that depends :)

It depends on what you are happy with, what sort of music you listen to, how much you want to spend, how big the boxes can be, whether you will have a separate subwoofer etc.....

Lowest piano note is 27.5Hz I'm sure that there are lower notes around from some orchestral instruments.... There is also the argument that to reproduce the sound faithfully there are harmonics even lower than the actual notes, so you should be able to reproduce those too.

I personally would want something with at least 35Hz as a -3db point, but the lower the better ;)

Tony.
 
well, if you dont listen to organ's or some funky tampi drum music 40 hz with -3 in the high 30's should do you just fine. My main's are flat to 35hz and the addition of two very large subs did squat for music. H.T. is another matter however. Hope this helps.
 
Hi, go as low as budget allows.
I went from 15inch Tannoys to Acoustic Energy AE1s. Stereo was much improved, bass was adequate but it lost that authority the big speakers gave. The spec for both speakers at the lo end was very similar. But the peak output for the small speaker turned out to be much less and I think it was the peak ability of the Tannoy that gave that extra apparent grunt ( but still not bass dominant).
regards Andrew T.
 
AndrewT said:
Hi, go as low as budget allows.
Well said :)
A quick flick through my CD collection will turn up some stuff with significant output in the low teens and others with nothing below 100Hz. I've also ventured round to a friend's place where his mains measure flat down to 17Hz in room (I trust his measurement) and some CDs sound totally different.
 
and others with nothing below 100Hz
This rings a bell. I have a producer friend who insists; "there is no MUSIC below 100Hz.
In popular music producers often pull it off in favour of increased power elsewhere. Commertial music is about being loudest. So its tonally distorted and compressed to hell. You don't notice the missing 100Hz on the radio. Its art not reality.

That's not to say your system should lack the capability of course.
 
No music under 100 Hz?

Pbassred:
As a bass player (from your nickname i guess you play Fender? I play Warwick) I'd be offended if someone told me there was no music under 100Hz, even if the one who said it was a friend :bawling:

Seriously tho, about going low, if the object is to go low in a small box, maybe an assisted sub such as a Linkwitz transform or a Critical Q sub would do the trick? Both are active systems, so they are a bit more complex and costly than a standard system, but seem to be good ways to extend low bass response in small boxes. I haven't tried these myself but the idea appeals to me. Also, you will be trading efficiency for extension and the driver needs to be selected carefully, as it is going to be stressed a lot more than in an ordinary setup.

/Andreas
 
This really depends on the size of the room, since room gain can do wonderful things for small subwoofers. I have a sealed 10" sub in .6 cubic feet that had a -3db at 25hz in a room that was 11'x10'x8'.

So how big is your room? Divide 573 by the longest dimension (in feet) of your room to get the target -3db point for a sealed enclosure.

If you are more than 1/3 of an octave away from the -3db point... IMO, add a passive radiator. So if the largest dimension of your room is more than 20 feet, I would stronly consider adding a PR... but only if you are very concerned about low bass.

Dan
 
OK I use peerless XLS 10" in a 20 litre sealed box with EQ to -6 ad 20hz. This suits music really well, if you try and play 20hz sine waves they quickly run out of excusion but for normal music plus of 30hz they go quite loud enough.

At 40hz the amp runs out of power before the speakers run out of xmax. The amp is 200 watts into 8 ohms. Well I start to hear distortion increase dramatically at this point, and I know th SAOR in the amp does kick on around here and makes a really horrible noise when it does.

But for music these are fine, AND allow very good WAF, being only 20 litres for a 10" driver and practically extension down to where we can hear, albeit NOT suited for home theatre.

I am going to purchase another pair of drivers and see what a push pull sounds like, with one XLS on the front of the cabinet and one on the back firing in opposite directions, should cancel out movement created my the drivers on the cabinet, and reduce distortion.
 
owdi said:
So how big is your room? Divide 573 by the longest dimension (in feet) of your room to get the target -3db point for a sealed enclosure.


The longest dimension is approximentally 15 feet, so that would give a rating of 38 Hz. However, this is for my parents, and they aren't concerned with having a flat response to 20 Hz. They just want me to replace the TV speakers which they've been using for who knows how long.

However, I do have a question regarding what you said. I'm a physics head, and I'm been wondering if it's possible to actually estimate the affect of room size on bass performence. You gave me the number 573. How did you get that number?

Also, I'm not planning on doing a sealed enclosure. I'm actually looking at a bandpass. Since the slope is deeper, I'm assuming this wouldn't work for me?

Thanks in advance!

Reece
 
However, I do have a question regarding what you said. I'm a physics head, and I'm been wondering if it's possible to actually estimate the affect of room size on bass performence. You gave me the number 573. How did you get that number?

(Speed of Sound)/(Longest Dimension of Room * 2) = Point at which your subwoofer starts behaving like a box within another box.

The speed of sound in dry air at 30*C/86*F is 1147 feet per second. I divided that number by 2 to get 573.

I'm definately not a physics guy, the above is just a rule of thumb I use. I like to keep it simple, no point in overanalyzing room response since it changes so much every time you move your head, your furniture, or your speaker.

If size is a big consideration, why are you going bandpass? Want to give us some details on which drivers you are using?

Dan
 
owdi said:
If size is a big consideration, why are you going bandpass? Want to give us some details on which drivers you are using?


I'm planning on using a tangband 5" subwoofer, model W5-1138SA. While it may not sound like too much, I can actually get the respose I want in a fairly small enclosure. I want to use a bandpass because of it's group delay. I ran simulations for this driver in a ported case, and it's top group delay was at or above 20 ms, which in my opinion is too much.

So my current case requires a 6 liter rear and 3 liter front vb, tuned to I believe 65 hz, making the total around 10 inches cubed, including wall size, etc, and predicted group delay is around 10 ms.

And, above all, the price is right at $25 a driver. ;)
 
Pbassred said:
err....
What is the frequency response of your Television? The guys (at our anon' Broardcast company) recon they actually transmit about 12K bandwidth but we don't know how low.

Have you measured the source? Are we thinking too much here?


I have not measured. However, I also have a Klipsch stereo, and there definitely a significant different between the two. :)

It's a 25-30 inch TV, so were definitely not talking home theater, or even a big screen with moderately sized speakers.
 
rjon17469 said:
I'm planning on using a tangband 5" subwoofer, model W5-1138SA. While it may not sound like too much, I can actually get the respose I want in a fairly small enclosure. I want to use a bandpass because of it's group delay. I ran simulations for this driver in a ported case, and it's top group delay was at or above 20 ms, which in my opinion is too much.

So my current case requires a 6 liter rear and 3 liter front vb, tuned to I believe 65 hz, making the total around 10 inches cubed, including wall size, etc, and predicted group delay is around 10 ms.

And, above all, the price is right at $25 a driver. ;)

Some general comments:

You are going to have problems fitting a port tuned to 65hz in 3L of space. Port size is critical in bandpass enclosures, since all output is through the port. At 55 watts you need at least a 2" port, which means it has to be nearly 18" long. At 25 watts you can get away with a 1.5"x9.5" port.

The bandpass enclosure you proposed is less efficient than a vented enclosure. A 9L vented cabinet tuned to 42hz would only need 10 watts to achieve the same output as your proposed bandpass enclosure at 25 watts.

Since the vented enclosure needs less than half the power of the bandpass enclosure, you can get away with a smaller port. Also, since the chamber for the vent is larger, it is easier to get the tuning you need. For example, the above 9L cabinet with a 1.75" x 9" vent (end of the vent should be 1" away from the back wall) would get you a low 40's tuning frequency and peak air velocity of 6% the speed of sound at 25 watts. To get the same output in the bandpass enclosure you would need 55 watts of power (because it's less efficient), which results in port air velocity approaching 10% the speed of sound with a 1.5" vent. If both ends are not flared, you will have port noise (which sucks, believe me).

Although peak group delay is higher for vented, this peak happens low enough that it's not a big problem. The vented enclosure would have lower group delay in the frequencies that matter (see chart).

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Finally, in-room response for the bandpass enclosure will be a bit peaky compared to the vented enclosure. See the below chart (room gain simulated with a linkwitz transform).

An externally hosted image should be here but it was not working when we last tested it.


sheesh, that turned into a bigger post than I thought. If you are dead-set on building a bandpass enclosure, I suggest you tune a big higher, maybe 72hz. That will soften the peak, and allow you to fit a 1.75" port in the measly 3L of space you have.

Dan
 
One more thing, with a bandpass enclosure, or with a small vented enclosure, you have to be worried about standing waves in the part of the cabinet that is vented. I once built a bandpass subwoofer that looked great in WinISD, but had over 24db of gain around 1000hz.

In your case, a 9" vent will behave like an organ pipe, creating a nasty resonance around 400hz. If you are using a 2nd order crossover, it will have to be set no higher than 100hz just to flatten out the peak.

Dan
 
owdi said:


Some general comments:

You are going to have problems fitting a port tuned to 65hz in 3L of space. Port size is critical in bandpass enclosures, since all output is through the port. At 55 watts you need at least a 2" port, which means it has to be nearly 18" long. At 25 watts you can get away with a 1.5"x9.5" port.




I was actually thinking about doing a passive radiator, which would eliminate the port issues, although it would result in a slightly higher f3.

So, the group delay peak isn't something I should be too worried about? If so, that looks like a better design.

I ran some simulations for ported boxes, and it's telling me for my driver I should use a 3" port, at a length of 33 inches. Would I want to stick with a passive radiator in order to keep things simple and size down?

Also, I've never used a passive radiator before, but I know how to calculate the mass required. However, does the passive radiator come with weights?
 
Re: No music under 100 Hz?

nuppe said:
Pbassred:
As a bass player (from your nickname i guess you play Fender? I play Warwick) I'd be offended if someone told me there was no music under 100Hz, even if the one who said it was a friend

Under 100Hz is where the grooooooove is baby.
I play Alembic.


To answer the original question, about 40Hz. If it's clean to there, then our brains with synthesise the fundamentals from the higher harmonics. But, when you have tight, clean extension to 20Hz you can feel it in the gut on movies and some music, but there really is little below 40Hz on most music discs.
 
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