The Wrong Way to Buy a Sub

Early B.

Typically, when determining which sub to purchase (primarily for HT), many of us look at two major factors -- how deep it goes and loud it goes. Does it really matter that much? Sure, if a sub is rated at approx. 25Hz or less, it should be fine for HT. However, a sub that goes deeper or louder doesn't necessarily make it better, does it?

Here's my point -- I'm wondering if we get caught up in looking at specs for subs and, to some extent, disregard what it sounds like. A woofer is a speaker, but we don't usually examine speakers in the same way. For speakers, the SQ is the single most important attribute, but for many of us, SQ is secondary in choosing a subwoofer.

For instance, many of us have said that the quality of a subwoofer amp is not terribly important, but we would never say that about an amp that powers our speakers. We would rather brag about how deep our sub digs or how loud it can play, but rarely talk about how good it sounds. There has been plenty of discussion about musical subs for 2-channel listening, but I rarely read threads about how someone's sub accurately portrays the bass elements in a movie. Or how someone upgraded their sub and found it to be more detailed and refined than what they had before.

I have no idea how deep or how loud my DIY sub can go, but it sounds great. Not trying to start anything, but just want to get a better understanding.

Thanks.


P.S. - is there a direct correlation between how deep a sub goes and its tactile ability?

lanion

The only facts on the internet are the specs.

PolkThug

Assuming the specs are accurate, they can tell a lot about the potential of a sub.

HOWEVER, a musical sub would be one in which the sub can return to its 'starting position' very rapidly after a bass note, IMO.

So, a sub that has good specs, could still be "muddy" or "booming" when faced with a rapid succession of bass notes. It appeared to have good specs in the first place because a sweep tone was used.

Schris22

Having a flat response curve is important in all speakers including subwoofers correct?

Other things may direct bias or cause dips in the freq curve but for the most part want a flat response curve for all speakers...I'm pretty sure...but correct me if i'm wrong.

Chris

McLoki

I do think that the amp used makes a large difference in the quality of the sound that comes out of a sub. I am suprized as well how many people consider a sub amp a secondary thought of just watts / dollar.

I have noticed a significant increase in quality of bass in upgrading the wire from my amp to my sub (I have a passive sub) from 16-18ga to 10ga. The bass seems much tighter and more controlled. It seems to be allowing the amp more control over the speaker than the wire I had before. This is in only a 7' run of speaker wire as well. There was more impact in the 7' wire run from my amp to my sub than their was in the 23' run from my amp to my front 3 speakers.

I think we look mainly at volume and depth for a sub because many of us are willing to modify any other paramaters that we need to flatten the response of a sub. i.e. - room and location have a huge impact on how a sub sounds. You can take the exact same sub/amp in 2 different rooms and have it sound very boomy in one and sound great in another just based on how the sub and room work together. due to that many people are willing to equalize a sub (where they wouldn't any other speaker in thier system) to flatten the response to what they want. Since bass energy takes alot of power, you don't want to increase any levels in your eq, just decrease them. Since all you are doing is cutting the volume at the peaks to flatten the response, volume is very important.

Depth is also very important for HT. (not as much for music unless you are into organ music). There are not that many tracks of music that have much content below about 30hz. There are very few movies (especially action movies) that DON'T have content in that region. Due to that, depth is very important. A good sub in an action movie should add a tacticle feeling to the movie. It has to move alot of air so you feel impacts not only in your chest, but in the walls, floor, and seating around you. If there is an earthquake or crash you not only need to see and hear it, but you should be able to feel like you are a part of it. The deeper you go, the more air moved and more feeling that is imparted during those scenes.

If the woofer is capable of playing pretty deep (in the 20hz range) at a decent volume, I think the quality of the woofer will be pretty high. The box and amp relationship to the woofer are what will make it "musical".

Michael

gregure

I agree the quality of the amp should be taken into consideration as well, however Hz extension is important for HT as well. Personally, I think the biggest test of a sub is the musicality of it. If it's rated to 25 Hz or below, you're going to get excellent results for movies in terms of feeling it in the gut. However, if you want to truly discern bass notes and get away from muddiness, take a few good songs with excellent bass lines that can get lost in a muddier sub, or really stand out with a good one. A few examples of songs I test subs with are:
1. Led Zeppelin-The Song Remains the Same
2. The Who-Baba O'Reilly
3. Fleetwood Mac-The Chain
From what I've heard, Martin Logan makes some of the most musical subs out there. The Grotto is such a great sub-small, compact, excellent depth (22Hz at -3db), and very musical. For $1000, it's a great deal, although some would say SVS gives you more extension for less money. I like my SVS but do find it to be a little boomy at times, although my Audioquest Jaguar used as a sub cable helped that a bit. There is just something about Martin Logan's aluminum driver, servo controlled, sealed box subs that is just truly amazing.

I also really like the new Brittannia series subs from REL. They are very musical, go really deep, and are attractive as well. The B2 is a monster. Heard some Metallica w/ some Vienna Beethoven speakers and a B2 for the sub and it sounded amazing. I would probably go REL over SVS any day, however the B2 is $2700, so it's a bit more of a jump. Really clean bass, though.

RuSsMaN

What I get a kick out of, is powered subs altogether (amp fastened TO the sub enclosure). Everything else in the system is isolated as much as possible, yet the sub amp is fastened to biggest source of vibes in the room.

Music is always first. I like charts and data, they are neat to have, neat to look over. At the end of the day, I need to put my ears on it, then I know if it's something for my rig.

Specs are a starting point at best. If you are a 'spec' guy, you'd laugh at some of the tube gear I have - until you heard it.

Cheers,
Russ

Early B.

RuSsMaN wrote:

What I get a kick out of, is powered subs altogether (amp fastened TO the sub enclosure). Everything else in the system is isolated as much as possible, yet the sub amp is fastened to biggest source of vibes in the room.

Gee, never thought of that one. Makes sense.

dkg999

My first ahaa with a sub was when I purchased a Signal Cable 12' power cord off of eBay just so I could get my SVS 20-39 PC+ in the corner of the room and still be able to plug into the Tripp Lite surge protector. In as direct of comparison as possible, the Signal Cable pc made a really nice improvement in the tightness and SQ of the bass. I was in the power cord non-believers club prior to that. In comparing subs, I have really found SQ to be a big variable. I am in an apt, so I don't get to run subs at high SPL's that give you the thump in the chest effect. Sometimes I think this focuses me more on how the sub sounds. Between my SVS 20-39, SVS PB10 and Polk PSW 505 and 303 there are significant differences in SQ. I sometimes don't understand the bashing of the Polk subs, as I would rate these from best SQ to worst SQ as SVS 20-39, Polk 505, Polk 303, and SVS PB10. The PB10 is a HT thumper and rumbler compared to the others.

unc2701

Yeah, my friend had this 15" cerwin vega that could hit 20hz no problem and cause a breeze in the hallway into the room that you put it in but it sounded like total ****. If you look at some of the best musical subs, (rel, for example), they've rarely got anything bigger than 10" and they engineer the hell out of the enclosure. Basically, I'd argue for putting moving mass as a spec- the range and the spl do not tell you how fast the driver can start and stop... Your ears will tell you best, but that's not always an option.

Dennis Gardner

I think it matters what you are going to use your sub for.................

Sub quality isn't as much of an issue as quantity at sub sonic freqs since we can't here as much as 10% distortion when delivered at those low freqs. (sub 20hz)

Sub quality (accuracy, speed, recovery) is an issue at the lower sonic levels of music though, and that is where to look for good performance. (20-35hz)

Basically for HT use, my dual 12 ported box tuned (to 17hz) is a rumble machine, but for music, I let my SDA towers handle my bass needs.