Subs: Ported or Non Ported?

[jocko_nc]

Guys:

Lots of subwoofer talk lately. Looking for your opinions on this.

I recently built a project 6.5 2-way using a Seas 1.00 textile dome and the Peerless HDS 6.50 mid-bass woofer. (There is a thread on this in Speakers...) After working on the crossover, I have been so thoroughly pleased with the result that I am probably going to use these as my main music and HT speakers. The sound detail is amazing. I had previously been a Vandersteen fan. These are a new sound at the least, therefore a novelty and new toy. Honestly, the detail is so much more pronounced than the Vandys, yet the clarity and soundstage do not really suffer. Vandersteens still have more depth, but that is at the expense of detail. Side-by-side, I could come to prefer the new guys. BOY IS THE WIFE HAPPY!

So here I am. My mains are lacking in low-end punch. Bless their little 6.5 inch hearts, but I need a subwoofer. (BTW, the Peerless HDS is a great driver.) My main use is 2-channel music. What are your subwoofer recommendations?

I have read about the Hsu and SVS products. PartsExpress Titanic 10 certainly looks attractive. Someone mentioned a DIY servo product in another post.

My room will be 13' 6" x 25" or so. I prefer music and the accurate presentation thereof. Preamp is a Yamaha RXV650, so I assume I have decent crossover control and a sub pre-out. I am thinking a non-ported design for more accurate sound. ???. What about a non-ported Titanic 10? Versus the others? If I want more volume in the future, I could just get another one. What about two smaller subs versus one larger? Which models would be preferrable for music? Is a servo-controlled design really better? Is one worth it?

Thanks,

jocko

[kexodusc]

Sealed subs have advantages in the sound quality department for sure, making them much more suited to music. This comes at the expense of SPL, and perhaps bass extension, for a given box volume.
I much prefer sealed subs. Get a 15" woofer and have your cake and eat it too.

I think there's something to be said about using 2 subs, in stereo positions in the room. If nothing else, it should balance any audible frequencies the subs give off (have yet to hear any sub become completely invisible). If you can place a sub close to the center, in between your two stereo speakers, I think 1 sub is probably evey bit sufficient. Cost/benefit is probably going to determine which way you go.

Can't say I'd recommend the 10" Titanic unless space is a huge concern. If you can build a cabinet, your options really open up.

[Woochifer]

Your room is pretty big, and as such, a ported sub might work well there. Smaller sealed subs benefit from the boundary reinforcement that you get with small to medium sized rooms. They also have a nice "musicality" about them, but they can sound anemic in a big room.

As kex said, you might want to look into a 15" sealed sub. That will give you the deep extension and the high output level. If you don't want to deal with a DIY kit, you could contact Acoustic Visions and see what they can build for you (they are a dealer for the Dayton/Parts Express drivers as well as Adire).

Whatever you do, I would highly recommend that you also go with a parametric equalizer to correct for any room-induced peaking. The actual in-room frequency response for subwoofers will typically produce at least one major problem frequency where the room interaction create a boomy peak and/or a cancellation. With careful positioning, you can find a location that minimizes these problems, and with bass traps, you can reduce these issues even further. But, a parametric equalizer allows you to fine tune the low frequency response, and by flattening out the overall response, you can more accurately set the subwoofer level. End result is fuller, deeper, and more accurate sounding bass. In general, equalized subs will sound better than almost any nonequalized setup, including much more expensive models. That reflects on how much the room interactions influence what you hear in the low frequencies.

[Peter Duminy]

Or here is a spin on an old idea from Energy announced day before yesterday:

http://www.marketnews.ca/news_detail.asp?nid=1133 (http://www.marketnews.ca/news_detail.asp?nid=1133)

PFP drivers are back by the look of things. ;)

[jocko_nc]

I can't say that space is a big concern, except that space in the middle of the wall (13' 6", which is small, IMO) will be occupied by my stuff, the furniture cabinet and the components, and the 52" DLP. A center channel was tough enough to place (currently not using one), a huge central sub just wouldn't fit there. Free space in the middle of the wall will be tough.

If you think there is something to two smaller subs, I could go that way. If it is a wash performance-wise, it may be a better way for me to go. The room will most definitely be set up with space to each side. Aren't two 10 x 250 watt subs cost equivalent to a 15 x 500 watt sub?

What about a "satellite" (anyone still use that word?) system with dual subs? Is there any way to pass different L and R signals to an internal crossover on each sub such that the bass is presented is in two channels? That could be nice for music. Would a subwoofer filter out the high frequency signals with onboard electronics? If so, could a full-spectrum "second zone" pre-out on the Yamaha, L and R, be used as input to the subs? (I have to look at it again to see what it has) Where is this going?

I actually relish a good DIY. My experience with the last project was beyond expectations. My tool collection is o.k. I can usually make do the hard way- with my hands- for a fine outcome. It just takes care, patience, and a little forethought. Assuming DIY is an option, what would you recommend?

Thanks as always.

jocko

[mixadude]

I use 2 of the the (DIY) Rythmik Audio (http://www.rythmikaudio.com/servo_product.htm) servo subs and my stage wall is 13.5 ft wide, but my room is not so deep at 17.5 feet. I have the subs together in the middle and notice no localization problems, but my main L/R respond very well to 40Hz, and I keep the mains set to large in the system setup, then tuned the subs in with a parametric and delay on them to suit. The sub amps do have Low Pass filters, and I have them engaged probably around 100Hz, but the setting on my system's sub out is set for 80Hz, and I do use the sub out on the system to drive them and not that LPF via mains speaker level stuff. Also I set the gain levels on the sub amps to match via a pretty good acoustic analyzer. I found the response of my 2 separate cabinets to be very similar and their sum to be very predictable, due to exacting cabinet/driver/amp tolerances, and the fact that they are operating in basically the same 1/4 space, and there is insignificant comb filtering due to placement/listening position problems.

The analyzer I tuned it all with is Smaart Live (http://www.siasoft.com/index.html) and am very happy with the subs. The analyzer shows flat to 20Hz and only a couple of dB down at 16 Hz, but I think it's my mic! 700 watts of these two 12" sealed servo-subs at maximum extension settings in my room is definitely a high sound quality heart massage. :)

BTW, they're in 16x19x19 OD (HxWxD in inches) very sealed cabinets and made out of 1" MDF and don't take up that much room, especially once ya hear, but don't notice em. :D

I subscribe to a twist in an old adage, sound should be heard and not seen :D

[kexodusc]

Your room is pretty big, and as such, a ported sub might work well there. Smaller sealed subs benefit from the boundary reinforcement that you get with small to medium sized rooms. They also have a nice "musicality" about them, but they can sound anemic in a big room.


I think this is a good point, what I was kind of hinting at about a 10" sealed sub...the larger the room, the less you can count on room gain for sealed subs. Transfer function is hard to predict in most rooms, but a good rule of thumb is speed of sound divided by 2 X longest length of the room. In this case room gain isn't being added until around 22 Hz or so (well, there's always some reinforcement above this point but hard to calculate).

Long story short, a 10" sealed sub with an F3 in the 30 Hz region is going to miss some bottom end. For music, this might not be all that improtant, for home theater you'll wish you had it.

Wooch brings up an excellent point about parametric eq'ing. In most rooms, some measure of equalization and/or bass boosting will be required. Well worth the $100-$150 it'll cost you to add a parametric eq.