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HTIP - Home Theater In Progress

The top two curves are the left and right. The lower one is th average of the two (shifted -10dB for clarity).

I'm not saying that the Q control didn't move the fr curve, just that if it did it wasn't by much and I can't tell exactly. When using pink noise the bass region is never 100% steady so it's pretty difficult to say that any movement of the Q knob had any effect. Even using the quicksweep function of TrueRTA will never get exactly the same result in the bass region.

Without understanding what the Q control is supposed to do to the signal I can't say whether the acoustics of the room are impacting it.

The good thing is that since the best location for the Hsu box is not in the only corner that I can put the SVS... I can use a y-splitter to do head-to-head comparisons very easily. I'll do some of that this afternoon.
 
The Q, in this case, refers to the loading of the enclosure on the woofer. It is not a simple concept. Ver basically, the Q of a speaker enclosure relates to the transient response, low end extension, peak output at the lowest frequency, and group delay. Technically, the most ideal enclosure/woofer Q for a vented enclosure is accepted to be 0.7. Lower Q tends to be less accurate transient response and "looser" sound.

In your measurements - only response - the difference in Q will only be realized at and around the cabinet's tuning frequency. So, if the cabinet resonance is at 19Hz, the difference between Q settings will be from about 15Hz to 25Hz.
 
yromj said:
I think it looks great! The bigger question for me though, is how does it sound?
Click to expand...

I want to do some more listening before I give a detailed opinion. It suffices to say that the 15H is no slouch. It goes very deep and is capable of playing very loud. What I want in my HT sub is to be able to feel really deep bass without it sounding all floppy. I want an imperceptible transition between the mains and the sub. I don't wan't to be able to tell when a sweeping bass note is being handed off between the speaker and sub.
 
Flint said:
Technically, the most ideal enclosure/woofer Q for a vented enclosure is accepted to be 0.7. Lower Q tends to be less accurate transient response and "looser" sound.
Click to expand...

What situations would benefit from a lower Q? The reason I ask is that HSU (pete) suggests that I use 0.3 or 0.5, saying that 0.7 may be too deep bass heavy for my room and listening level.
 
Low Q is good for boosting the audible output of the low bass because the output is slower, floppier, and boomier than ideal. nearly all subwoofer owners vastly prefer more "OOMPH" than a truly accurate subwoofer sound would provide. Also, lower Q typically means higher SPL capability. So, to get peak SPLs without building a better (costlier) sub can be attained.
 
Hmm, that's a different definition than what's given for "Q" on a parametric equalizer; there the "Q" refers to the width, or frequency spread, of a given boost or cut, i.e. is it a skinny bell curve or a fat one.
 
The term "Q" means, literally, quality. It means different things depending on context.

The Loudspeaker Design Cookbook has a whole chapter on the concept of Q in the context of speaker cabinet design.
 
Botch said:
Hmm, that's a different definition than what's given for "Q" on a parametric equalizer; there the "Q" refers to the width, or frequency spread, of a given boost or cut, i.e. is it a skinny bell curve or a fat one.
Click to expand...

The Q in a parametric equalizer is the ratio of the 3dB bandwidth to the center frequency, which is essentially what you said.
 
I'm gathering from all of this discussion that the Q value (as it pertains to this discussion) essentially changes the sub's efficiency. Low Q=higher low frequency output at a given wattage at the expense of accuracy, high Q=more accurate sound but with a higher power demand to achieve the same SPL as the lower Q.

That it's safe to assume (as long as the sub doesn't run out of headroom) that using the highest Q setting should be preferable if accuracy is the objective.

Right?
 
I happened to end-up at a Best Buy toady so I picked-up another Xbox 360 for the HT (I have one in the living room) to be able to stream music from my PC. Works great! I can't believe that more people don't take advantage of the Windows Media Center integration. INMHO it has a pretty darn slick interface and, more importantly, it just works.

I'm thinking that I may just need to add another display for the times that I want to play music over th network without firing-up the projector. The trick will be to make it as inconspicuous as possible, but still be usable. The options are to put an HDMI monitor in the equipment rack, on the table (behind the main seats) or on the floor in the front-right corner.

Thoughts?

DSC_1196.jpg
 
Where is the equipment rack? If it's at the back of the room, I vote for that spot. No need to see the screen.

BTW, that sub is fucking huge....the way it should be.
 
Towen7 said:
I'm gathering from all of this discussion that the Q value (as it pertains to this discussion) essentially changes the sub's efficiency. Low Q=higher low frequency output at a given wattage at the expense of accuracy, high Q=more accurate sound but with a higher power demand to achieve the same SPL as the lower Q.

That it's safe to assume (as long as the sub doesn't run out of headroom) that using the highest Q setting should be preferable if accuracy is the objective.

Right?
Click to expand...

Yes, a higher Q would be the best choice if you desire the highest accuracy. Well, for that sub specifically.

Q impacts the "tightness" of the sound as much as the output. How fast can it respond to stimulation and how fast can it stop moving when the stimulation stops is greatly affected by the loading, or Q, of the enclosure. A Q of 0.7 (for a system) is the closest to ideal for a vented system.
 
jamhead said:
BTW, that sub is fucking huge....the way it should be.
Click to expand...
I would recommend a velvet or something like it to cover the top of sub to reduce the reflection.
 
I put a 19" LCD PC monitor with DVI and HDCP support in the rear of my room. Works like a champ.
 
I know im way late here......room looks AMAZING!

I have just one suggestion, paint the ceiling a darker color, you would be surprised at just how much more "pop" you will get ouit of the quality of the picture. ;)
 
THANKS!!

With the holidays and all I haven't done anything else to the room. I'm coming around the idea of painting the woodwork once the doors and shelves are put on and would definitely go with a darker color.
 
Don't listen to him! :happy-smileygiantred: Paint it! If you decide to re-stain it down the road you'd have to sand it down any way. Do what you gotta do to realize your vision.
 
Id rather not paint but here's the situation: It's going to be very expensive to build the doors/shelves in ash to match the existing woodwork because of some beetle problem that has made ash very hard to come by. Oak is less than half the cost but it cant be stained to match. Even if I got the ash the existing stain is more than 25 years old and will be tough to match exactly. There are some pait splotches (sloppy job by previous owners) and a bunch of knicks and gouges that need repair so the whole room really needs new stain. That's crazy expensive and if I were to go through that trouble I'd just assume remodel the whole space.
 
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