front or down firing sub whats the best for music?

[Bush thug]

so i am talking to  a friend  who thinks down is better for a sub as they only produce low frequencies and  shouldn't matter but in my head if a sub has the ability to produce higher frequencies so facing down would eliminate those frequencies  and would be like turning your speakers to the wall but i am not a professional and this is only an assumption so help would on my decision would be appreciated.

its for a focal surround setup 700v chorus i just want a little more bottom end when down low for music but i don't want to compromise the quality. 

[Paul Spencer]

Short answer - you don't need a sub to be down firing for that reason. Subs have a low pass filter which rolls off above a certain point which is user selectable on any plate amp.

 

There are pros and cons with down firing subs. The advantages are mostly practical, that the driver is out of sight and less likely to attract the attention of kids and cats. No grille is necessary to protect the driver and this is good because modern drivers have high excursion and can hit the grille unless it's very deep. The biggest downside is that the cone will sag over time and this will affect performance.

 

My advice is don't choose a downfiring sub over front firing unless you have issues with kids/cats or the sub you want for other reasons just happens to be down firing.

[WhakPak]

if you're specifically talking about subs for music, probably more relevant to the discussion is whether servo control or not...

[andyr]

if you're specifically talking about subs for music, probably more relevant to the discussion is whether servo control or not...

 

OK ... I'll bite!   Should a sub which is used for music be servo-controlled or not?

 

Regards,

 

Andy

[Paul Spencer]

A servo is not essential for accurate bass. They do certainly have advantages, but you can get a very good result without. Any high quality sub with appropriate room treatment, EQ and integration will disappear completely when setup correctly. You can remove every last trace of the kind of boomy doof doof bass that people improperly associate with subs, if done right.

[WhakPak]

...yes to all that, but I'd add that servo designs are often advocated for music applications in particular. But of course there are good sub designs that use non-servo technology to get good results. Rythmik use servo, SVS do not. Both are capable designs.

[mpearce38]

I'll take a well designed down firing sub over a poorly designed front firing sub, my point is it is all up to the execution and some manufactures do a better job then others with either format. I have a down firing MJ Acoustics sub, which is the most musical sub I have owned and also the smallest. It is incredibly quick which is what makes it so nice, and the on board adjustments make it easy to integrate.

 

Your friend is correct, the human ear is not so great at localising bass notes, room modes and phase cancellations make this even harder so it would depend on how high you wanted your sub to crossover, Physcio acoustically when you are able  to localise the position of a bass instruments image say a kick drum it is the high frequency component of the sound (the click of the mallet on the drum skin) which provides the tigger for your brain to pick up on the direction of the sound, not the bass componet.

[Itsmoi]

Would have thought that the difference between a sealed or ported sub be more relevant for musical use.

[betty boop]

I wouldn't worry about front or down firing. It doesn't matter.

[Paul Spencer]

Would have thought that the difference between a sealed or ported sub be more relevant for musical use.

 

Yes, it would be more relevant but it's not as simple as many would like it to be. I'll put it this way - were I to set up both a sealed and ported sub, both fully integrated, I doubt anyone could identify if they were hearing a ported or sealed sub. Once a sub is correctly integrated, no clues should be left that it's either sealed or ported or that a sub even exists at all. The bass should simply be there, showing up when and where the music demands.

[henry218]

from engineering perspective, PORTED will have higher group delay.

 

but like paul said, it doesnt really matter, i actually just compared between the 2, one is with dynaudio 12" sealed and the other one is Eminence Kappalite 3012lf in ported, they both have similar Fb 38hz, and surprisingly the bass sounded similar, only the dyn have a sense of thickness to it and the 3012LF have better slam and attack.

 

 

[Bush thug]

can somebody explain servo design to me please?

 

I'll take a well designed down firing sub over a poorly designed front firing sub,

 

this is a fair call but that goes with almost everything you get but say the design was of same quality design  for the type of sub what would be the choice?

 

 

 Any high quality sub with appropriate room treatment, EQ and integration will disappear completely when setup correctly. You can remove every last trace of the kind of boomy doof doof bass that people improperly associate with subs, if done right.

so as long as i get a quality sub in either direction a lot  of it depends on set up?

[Paul Spencer]

The most important factors are, in no particular order:

 

1. Quality of the sub and it's suitability in terms of output, extension and absence of problems like ringing, high distortion and compression

2. Damping of modal ringing

3. Frequency response in the listening position

4. Group delay (related to frequency response except where DSP is used to correct)

 

Note, I'm not saying those are the only things that matter!

 

Downfiring vs front - that's mostly pragmatic

Sealed vs vented, servo vs non  - just different tools to get a result

 

Bass traps, EQ, DSP, placement, multi subs, crossovers & integration - those are also tools and they are often more significant in terms of subjective sound quality.

[davewantsmoore]

so i am talking to  a friend  who thinks down is better for a sub as they only produce low frequencies and  shouldn't matter but in my head if a sub has the ability to produce higher frequencies so facing down would eliminate those frequencies

 

It depends on the crossover frequency and slope between the subwoofer and the main speakers.

 

Generally this point would be around -6dB @ 100hz (24dB/octave)....   If you're trying to play frequencies higher than this, then the orientation and location of the woofer will begin to matter.

 

 

this is a fair call but that goes with almost everything you get but say the design was of same quality design  for the type of sub what would be the choice?

 

As Paul has already said it's basically irrelevant  (the answer to your last question is absolutely yes) ....   Provided that a subwoofer is not being used beyond its design brief (ie.  SPL vs Distortion) ....  Then subwoofer sound is 90% to do with the setup (EQ) and the room.

 

 

can somebody explain servo design to me please?

 

A feedback loop is used to prevent unwanted movement of the cone.    Similar in principle to negative feedback in amplifiers.

 

http://en.wikipedia.org/wiki/Subwoofer#Servo_subwoofers

 

 

 

from engineering perspective, PORTED will have higher group delay

 

This is a dangerous generalisation for the subwoofer purchaser.

 

It is true...  Yes....  until you use DSP to modify the high pass response of the subwoofer, when you can achieve any GD you design for.    This means that many sealed subs on the market (using DSP, or other active electronics) may have a GD which approaches a ported design.

 

That is, unless the subwoofer (or the system) uses phase linearisation, when GD may = 0 .... but that is a more advance topic than this thread is tackling.

[Perth.hifi]

The rythmik F15HP and F12HP are Servo subwoofers, add you all know. So are they great? Was about to very a pair of svs sb13 ultras for 5.65m x 4.5m theatre room, but now I'm on the fence. ... room will be 40% music, 60% movies, but want best of both. ...

[bvuka2013]

I've been experimenting with a couple of Miller & Kreisel subs that I've recently purchased on Ebay

 

VX7 Mk2 - front firing

VX100 Mk2 - downward firing

 

Both are sealed enclosures and use 100W 8" drivers, but the VX100 is much easier to integrate into my 2 channel system

With the VX7 I just can't get it to gel properly in terms of both volume level & crossover point

 

I've relegated the VX7 as a secondary sub to the rear of my rumpus room for surround sound