Subwoofer Bottom-out

[Tdekany]

Was the system calibrated?

If you think that an 8" woofer isn't good for HT, check out the HSU STF1.

 

[shokhead]

For the money,thats a fine sub but what do you think it does for movies in the 20-25Hz? Thats where a good 12" woofer will start to work. Wont find a 8" doing 20Hz @105db,at least i dont think so.

 

[warnerwh]

There is a M&K sub the guy is asking 550.00 for on audiogon.com. This is an excellent sub with 2 12's and will do all you ask and then some. It's a much better deal than a new sub. Save your money and get something better used.

 

[S.R. Johnson]

For the money,thats a fine sub but what do you think it does for movies in the 20-25Hz? Thats where a good 12" woofer will start to work. Wont find a 8" doing 20Hz @105db,at least i dont think so.

That is true but I have an AR dual 8 inch sub that can play down to 25hz.
and I think some 8" can play good for a small room. But it is true what Caroll Shelby said and i quote "Too much power is almost enough!"

 

[shokhead]

Dual is abit different then a single. Playing down to 25Hz is one thing,playing it loud enough to be useful is another.

 

[Buckeyefan 1]

I've got 4 top quality 7" subs in my $1100 towers with all the power needed to drive them and all the technology available to make them sound great, and they can't touch a quality 12" sub which is properly placed.


"There is no replacement for displacement."

 

[shokhead]

I bet the bass they do produce is pretty dam cool sounding,right? I almost got some towers with built-in subs,they had just started doing that but were just out of my price. I think they were BA. Having those with a sub would be killer i would think.

 

[Buckeyefan 1]

Yeah, but being from the old school of music, I like to listen to my towers without the sub (music). You get spoiled with a subwoofer. I get very spoiled with my two 12's in my F150 XLT and a massive class D amp. It hits so hard with the Yes and Rush cd's. I have to admit, not much sounds better than my home system playing BNL. It's just hard trying to fill such a large room with one 12" sub and 4-7" woofers compared to a vehicle and 2 12's. It's just not fair!

 

[slopoke]

12" drivers.

Go listen to a Mirage OM-200 with dual 8" drivers. Flat down to 20hz and plenty of power unless it's a large room.

 

[shokhead]

Yeah, but being from the old school of music, I like to listen to my towers without the sub (music). You get spoiled with a subwoofer. I get very spoiled with my two 12's in my F150 XLT and a massive class D amp. It hits so hard with the Yes and Rush cd's. I have to admit, not much sounds better than my home system playing BNL. It's just hard trying to fill such a large room with one 12" sub and 4-7" woofers compared to a vehicle and 2 12's. It's just not fair!

How do you have all that hooked up with powered subs in the towers and a seperate sub? Do you set your 3805 to LFE+Mains?

 

[annunaki]

Go listen to a Mirage OM-200 with dual 8" drivers. Flat down to 20hz and plenty of power unless it's a large room.

What is the reference spl???? What frequency is it flat from?

 

[slopoke]

Om-200

What is the reference spl???? What frequency is it flat from?

Here are Mirage's specs:

OM-200
System Type Omnipolar Subwoofer
Power Output 800 watt dynamic peak, 200 watts continuous
Woofer 2 - 8” Polypropylene Titanium Deposit Hybrid
Magnet Size 28 oz.
Voice Coil Diameter 1.5”
Frequency Response 20Hz-120Hz +- 3db
Phase Control Continuously variable from -180° to +180°
AV Switch 0/+3db
Variable Low Pass Filter 40Hz -120Hz @ 18 db/octave
Inputs Low level input, crossover bypass, high level
Outputs High Level
Dimensions inches: 16-1/4 x 18-5/8 x 17-1/2 cm.: 41.3 x 47.4 x 42.5
Finish Black High Gloss, Cherry
Weight 70 lbs. 32 kg

I've measured it myself (using a Radio Shack SPL meter and Rives Audio CD corrected for the meter inacuracies) from 12 feet (Not near field) and pink noise set at 75db. The receiver was connected to the sub through the Xover bypass with the AV switch set to off. What I measured was a rapid rise from 18hz to flat (75db) at 20hz with a +2db rise above that starting at around 30hz. At 20 to 25hz you get a lot of port chuffing with a sine wave input but this isn't really noticeable in real life operation. (Test DVDs: Monsters Inc, LOTR Return of the King)

Obviously 200 watts won't do it in a large room but it's fine for an average sized one. And, the 2 8" drivers have very quick response making this a quite musical sub and not at all muddy.

 

[annunaki]

I am not stating that it is a bad subwoofer, I was simply pointing out that specs are not always what they seem. If the sub measured 20hz-120hz +/-3db (anechoic) but was only at 75db it would not be all that impressive in the home. However, if it were 20hz-120hz +/-3db (anechoic) at 115 db, one would have a sub to be proud of. Which would you choose?

 

[shokhead]

Yep. I think thats where some get fooled. This sub is rated doen to 25Hz. Well it might be but at 80db,what good is it. Would i rather have a sub do 25Hz at 85db or a sub doing 30Hz at 105 db? 30 anytime. Low is good but low and loud is better.

 

[slopoke]

I am not stating that it is a bad subwoofer, I was simply pointing out that specs are not always what they seem. If the sub measured 20hz-120hz +/-3db (anechoic) but was only at 75db it would not be all that impressive in the home. However, if it were 20hz-120hz +/-3db (anechoic) at 115 db, one would have a sub to be proud of. Which would you choose?

Note that Mirage's specs don't specify any db level. Nor would I expect them to. They don't know what room the sub will be placed in.

With all the room mode issues that go along with bass reproduction a "near field" measurement that gives a db spec is almost useless. That's why I gave you a real world measurement in "my" room at a "reference" level. Not that it can usefully translate to anyone else's environment. I will say the this sub can shake my whole house, but once again that means nothing to someone with a different room.

Let's go back to my original comment on this thread though. I wasn't stating that this was a great sub, only that a decent low end extension could be had from a sub with 8" drivers. I think that 20hz spec proves this out regardless of any SPL level specs.

 

[shokhead]

Really? So why should they give us any spec's? 20Hz @,oh lets say 80db,is that ok for a HT? IMO,i dont think you can get a decent low out of a single 8" subwoofer. Whats decent. Well i'd say for HT it might be 20Hz@100-105db.

 

[annunaki]

Note that Mirage's specs don't specify any db level. Nor would I expect them to. They don't know what room the sub will be placed in.

With all the room mode issues that go along with bass reproduction a "near field" measurement that gives a db spec is almost useless. That's why I gave you a real world measurement in "my" room at a "reference" level. Not that it can usefully translate to anyone else's environment. I will say the this sub can shake my whole house, but once again that means nothing to someone with a different room.

Let's go back to my original comment on this thread though. I wasn't stating that this was a great sub, only that a decent low end extension could be had from a sub with 8" drivers. I think that 20hz spec proves this out regardless of any SPL level specs.

Your point is understood. For most people a sub with 8" drivers may go low enough. The point previously made was, can it reach those low frequencies with enough mustard to keep up with the rest of the system without sounding stressed? I would say in most instances no. If the system's mid to high range speakers are reaching 100db+ levels but the sub can only do 25hz-30hz up to 80db-85db it will definitely not sound right.

My point was that there needs to be reference db level at which the specs are taken. I am not picking on the Mirage in particular. Subwoofers should be subject to the same scrutineering as speakers. An example of suggested specs on a subwoofer: 20hz-120hz +/-3 db (anechoic), 115db at 2 meters, w/full rated rms power, unclipped. My view is that if a reference level in db is stated it may give a better idea of possible real world performance.

 

[bros400pgm]

Can you please explain? I have the same yammie. Do I have to set the crossover on sub at max, and let the amp handle the LFE? Cannot understand as i am new to HT systems.

Can you expalin the exact process from the LFE channel to the sub concerning the crossover?

 

[johnu]

Let's go back to my original comment on this thread though. I wasn't stating that this was a great sub, only that a decent low end extension could be had from a sub with 8" drivers. I think that 20hz spec proves this out regardless of any SPL level specs.

I guess it depends on what you consider to be decent.

What I measured was a rapid rise from 18hz to flat (75db) at 20hz with a +2db rise above that starting at around 30hz. At 20 to 25hz you get a lot of port chuffing with a sine wave input but this isn't really noticeable in real life operation. (Test DVDs: Monsters Inc, LOTR Return of the King)

Hmmm, 75db is not very loud as loud goes for the average scene, and peaks would go 20-25+ db's higher. And you are getting port chuffing at 75db's? I wonder what the numbers look like at 85 or 95 db's since port chuffing at 25hz doesn't sound promising. I'm guessing you probably aren't getting much useful bass below the 30++ hz range at reference levels.

By way of comparison, my bookshelf speakers with a single 8" woofer are rated down to 42hz @ +-3db (and sound fairly good on bass if I turn the subwoofer off) and good floorstanders might be in the low to mid 30hz range. I think this subwoofer would be useful if you had main speakers with very limited bass capabilities (maybe 60-70+ hz), but not if you wanted room shaking bass.

 

[shokhead]

Yep. Like i say,there's a difference between bass and LFE.