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post #6751 of 6776 Old 04-08-2014, 07:31 AM
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I had experimented for some time using just the F112's low pass filter (trying to match the rolloff of my mains) but was never satisfied with the result when compared to what my preamps could do; but at the time my focus was on blending, not localization. My preamps have both been fixed to 12dB slopes (previously a McIntosh C39 and now an Emotiva XSP-1). The problem was (based on the best of my relatively limited understanding) that I was trying to match my ported mains (B&W 805Ss) with a sealed sub, which, due to phase shifts from the ports, is essentially impossible without a high pass on the mains (which I didn't have available with a 24dB slope anyway).

While the XSP-1, with a fully variable crossover from 50-250Hz, does afford me some new tweaking opportunities, I'm not very anxious to go down that road again. I've left it at 80Hz, which I'm convinced is near the lower workable limit for my mains, and am perfectly happy now that I have 2 F112s. Still just running the second slaved, although I must admit I have been tempted to move to a 2.2 setup...
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post #6752 of 6776 Old 04-11-2014, 07:22 AM
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I listened to a F113 at a dealer yesterday using the WOTW clip.

It was in a basement, and the room is large, I'm guessing at least 6000 cu ft. , probably closer to 8000. The volume was set to -20dB.

This is my first time hearing WOTW on a real subwoofer, however I walked away disappointed. While it was clearly rattling the walls, and I can feel the bass rumbling my shirt throughout the clip, it wasn't a visceral experience. The floor did not shake at all. I felt nothing in my chest. I didn't feel like the "I was there" and visceral feeling that many describe.

How is WOTW supposed to "sound" and "feel" like on a F113? Am I just expecting too much?
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post #6753 of 6776 Old 04-11-2014, 08:52 AM
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Quote:
Originally Posted by LowerFE View Post

I listened to a F113 at a dealer yesterday using the WOTW clip.

It was in a basement, and the room is large, I'm guessing at least 6000 cu ft. , probably closer to 8000. The volume was set to -20dB.

This is my first time hearing WOTW on a real subwoofer, however I walked away disappointed. While it was clearly rattling the walls, and I can feel the bass rumbling my shirt throughout the clip, it wasn't a visceral experience. The floor did not shake at all. I felt nothing in my chest. I didn't feel like the "I was there" and visceral feeling that many describe.

How is WOTW supposed to "sound" and "feel" like on a F113? Am I just expecting too much?

That's a pretty big room for one 13" subwoofer. -20db is pretty low for volume too for the whole theatrical experience.

In my smaller room of about 2000 cubic feet, that movie is pretty violent. My floor shakes. I'm not saying the F113 is the be all end all, but it in most rooms for its size its gotta be one of the best.

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post #6754 of 6776 Old 04-11-2014, 11:57 AM
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Originally Posted by mookie b View PostThat's a pretty big room for one 13" subwoofer. -20db is pretty low for volume too for the whole theatrical experience.  In my smaller room of about 2000 cubic feet, that movie is pretty violent. My floor shakes. I'm not saying the F113 is the be all end all, but it in most rooms for its size its gotta be one of the best.

Plus unless you room has suspended hard floor you are robing the sub :)

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post #6755 of 6776 Old 04-13-2014, 01:58 PM
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Great tutorial by one of the JL audio peeps:

http://soundoctor.com/whitepapers/subs.htm

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post #6756 of 6776 Old 04-15-2014, 11:53 AM
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Originally Posted by blazar View Post

Great tutorial by one of the JL audio peeps:

http://soundoctor.com/whitepapers/subs.htm


Essentially the same paper is available on JL's website:

https://jlaudio.zendesk.com/entries/22530915-Adding-a-Subwoofer


There are a variety of issues with fact and concepts in the paper. Below are a few excepts from the paper along with comments. Please refer to the paper incase more context is needed. I own both ported and sealed subs so personal preferences aren't the question here.


"That's an IMPULSE. It's actually the leading edge of a square wave, with a little slope to it. A square wave by definition has a fundamental and only odd harmonics. A sine wave has only it's fundamental frequency, and a triangle wave is the fundamental and only even-order harmonics. So the impulse of a kick drum is nearly a square wave, with some sine wave fundamental and some even order harmonics, but less than the odd order harmonics present in the square wave part."

Issue: Triangle waves are actually made up of only odd-order harmonics. The higher order odd-order harmonics are present in lower quantities than with a square wave. Unfortunately this error may show a lack of basic understanding of the math and physics involved.


"As you go lower and lower in frequency, at some low frequency the air pressure from the LF driver and the air pressure from the port are exactly opposite each other, so they cancel, and there is no more audio at that frequency: it disappears. This defines the -3dB "cutoff" point of the cabinet in question. When the manufacturer of a speaker cabinet defines the frequency response (i.e., 37 Hz - 20kHz +/- 4dB) this is what is defined by the entire arrangement of the port and the air in the cabinet and the driver."

Issue: The point at which the audio disappears, if that actually occurs, would be at 0dB (no) output, not the -3dB cutoff point.


"A ported sub for home use is even more wrong than ported mains. Now you would be attempting to acoustically add together in the room at least SIX low frequency sources with differing phase and frequency slope conditions: the LF drivers in your two mains, their ports, the sub driver, and its port. In addition, since it's a bandpass it cannot go down low enough for serious Home Theater effects."

Issue: Numerous ported subs are available with output low enough for home theater use. Most, if not all actual movie theaters use ported subs, from companies such as JBL and Meyer sound.


"Lets ("Let us" on JL site) examine ported speakers. We'll start with the worst case, the port in the front. At mid bass frequencies, say 50-80 Hz, the LF driver moves IN the cabinet, the air in the cabinet is elastic, and the port air moves out of the cabinet. Because of the frequency at which the cone is moving, by the time the cone moves back out again, the port air is now moving out, so in front of the cabinet the two air pressure sources sum together and you get a fake bass "bump" or "boost"."

Issue: Here we have a new term, "Fake bass." Again, movie theaters use ported subs. Are they providing fake bass? Other than defining it as coming from ported subs, what is the definition of fake bass and how is it measured?


"A similar situation exists with home theater setups where the customer THINKS that the front speakers are "full range". Even so, the BEST approach is to seal the ports, operate the 5 channels as "small", crossover at 80 (or even a bit higher, but NEVER lower) and correct the timing issues inherent in all modern subs by setting (in the receiver or processor's setup menu) ALL the distances THE SAME, and to a small number such as 7 feet; then set the sub to 12 feet MORE (i.e. 19 feet) and THEN use the variable phase control on the sub to fine tune the relationship at the 80 Hz crossover point. Some better speaker companies that make "large" speakers (such as B&W) are aware of this port issue and supply port plugs just for this purpose. Kudos to them."

Issue: The advice to set all speakers to the same distance in a surround setup would seem to contradict every other source on how to set up surround speakers. Evidently Audyssey, all the AVR manufacturers, and a lot of other folks have gotten it all wrong.


"And again, as a point of reference, "flat" response in the frequency domain is FAR AND AWAY the LEAST important phenomena: impulse response in the time domain is the most important, but it cannot be measured with a handheld meter therefore almost everyone simply ignores it."

Issue: Frequency response and impulse response are directly related. If one is known the other can be derived. If one is changed then the other changes, they are not independent.


Enough...
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post #6757 of 6776 Old 04-15-2014, 12:41 PM
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Haha i knew someone would dump all over that article's stance on ported subwoofers...

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post #6758 of 6776 Old 04-15-2014, 01:08 PM
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Originally Posted by blazar View Post

Haha i knew someone would dump all over that article's stance on ported subwoofers...
Yeah, someone who knows what he's talking about. wink.gif
Clearly the author of the article does not. rolleyes.gif

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post #6759 of 6776 Old 04-15-2014, 01:47 PM
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Well, the author is clearly Barry Ober, who I believe used to contribute to this thread. Can't vouch for his credentials, but it appears they are fairly extensive (and readily available online, unlike his newfound critics wink.gif). Why not email him and get his response?
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post #6760 of 6776 Old 04-19-2014, 05:49 AM
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Originally Posted by stephenbr View Post

My F113 ended up needing a new power supply - couple of hundreds of dollars and I am back in business.

My f112 is going in on Tuesday. I think it's the power supply as well.

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post #6761 of 6776 Old 04-19-2014, 03:57 PM
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My f112 is going in on Tuesday. I think it's the power supply as well.

Hopefully it is as quick and easy as it was for me.
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post #6762 of 6776 Old 04-19-2014, 04:15 PM
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Originally Posted by Franin View Post

My f112 is going in on Tuesday. I think it's the power supply as well.

Bummer, mate. Hope it goes smoothly. Like Vegemite on a piece of toast.biggrin.gif

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post #6763 of 6776 Old 04-19-2014, 08:08 PM
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Hopefully it is as quick and easy as it was for me.

Thanks! I was told that the back plate is the hard part to get off so hopefully the technician over here won't have any trouble.

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Bummer, mate. Hope it goes smoothly. Like Vegemite on a piece of toast.biggrin.gif

Me too

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post #6765 of 6776 Old 04-22-2014, 07:08 AM
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Dropped mine off today, who knows how long it will take.

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Dropped mine off today, who knows how long it will take.

It won't take too long. It will be worth it.

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post #6767 of 6776 Old 04-23-2014, 06:41 AM
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It won't take too long. It will be worth it.

Hope so.

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post #6768 of 6776 Old 05-03-2014, 02:40 AM
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Picked up my sub yesterday, I'm glad its back at home smile.gif

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Got a pair of f212 for sale if folks are interested. Some swirls on the black lacquer but otherwise great. PM me, they are 7k+ shipping.

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post #6770 of 6776 Old 05-03-2014, 08:25 AM
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Quote:
Originally Posted by LowerFE View Post

I listened to a F113 at a dealer yesterday using the WOTW clip.

It was in a basement, and the room is large, I'm guessing at least 6000 cu ft. , probably closer to 8000. The volume was set to -20dB.

This is my first time hearing WOTW on a real subwoofer, however I walked away disappointed. While it was clearly rattling the walls, and I can feel the bass rumbling my shirt throughout the clip, it wasn't a visceral experience. The floor did not shake at all. I felt nothing in my chest. I didn't feel like the "I was there" and visceral feeling that many describe.

How is WOTW supposed to "sound" and "feel" like on a F113? Am I just expecting too much?

Need more power, more subwoofer surface area for that size room

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post #6771 of 6776 Old 05-03-2014, 01:16 PM
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Originally Posted by blazar View Post

Need more power, more subwoofer surface area for that size room

The reason I ordered two F113's to begin with. Thinking of adding either two more. Two Gotham subs were a thought at one time.

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post #6772 of 6776 Old 05-07-2014, 12:21 PM
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Originally Posted by Sharp1080 View Post

The reason I ordered two F113's to begin with. Thinking of adding either two more. Two Gotham subs were a thought at one time.

Same here - I had considered Gothams. But when we struggled getting the fathoms down the stairs into the basement I knew I didn't have enough friends to help with moving the Gothams, lol.

Saw and heard the Gothams at a friend's place and they are beautiful and powerful.

Just a followup with my subs - I replaced the dsp unit (thanks to Barry Ober and Dave at Gemsen) for a very reasonable few hundred bucks. The instructions were very good and it wasn't too bad. No extraneous
noises and I'm amazed at how much better things sound. Hadn't realized over time that the sound from the 1 sub was "off" and it did affect the overall sound. Had me stumped why I wasn't getting the same visceral bass
but just kept tweaking the Trinnov eq settings.

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post #6773 of 6776 Old 05-07-2014, 04:39 PM
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I read your feedback from earlier posts regarding using 4 JL Audio subs and that's when I realized I needed 2 more to get it perfect in my room. It's your fault! wink.gif

Glad you got it sorted out!

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post #6774 of 6776 Old 05-07-2014, 04:55 PM
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Originally Posted by Sharp1080 View PostThe reason I ordered two F113's to begin with. Thinking of adding either two more. Two Gotham subs were a thought at one time.

Gotham $$$$$$

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post #6775 of 6776 Old 05-07-2014, 06:48 PM
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Originally Posted by Sharp1080 View Post

I read your feedback from earlier posts regarding using 4 JL Audio subs and that's when I realized I needed 2 more to get it perfect in my room. It's your fault! wink.gif

Glad you got it sorted out!

lol, thanks. cool.gif

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post #6776 of 6776 Old 05-11-2014, 09:25 AM
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Originally Posted by The Bogg View Post

Same here - I had considered Gothams. But when we struggled getting the fathoms down the stairs into the basement I knew I didn't have enough friends to help with moving the Gothams, lol.

Saw and heard the Gothams at a friend's place and they are beautiful and powerful.

Just a followup with my subs - I replaced the dsp unit (thanks to Barry Ober and Dave at Gemsen) for a very reasonable few hundred bucks. The instructions were very good and it wasn't too bad. No extraneous
noises and I'm amazed at how much better things sound. Hadn't realized over time that the sound from the 1 sub was "off" and it did affect the overall sound. Had me stumped why I wasn't getting the same visceral bass
but just kept tweaking the Trinnov eq settings.

The other night I sent an email to Barry and Dave at JL/Gemsen thanking them for their help sorting things out. That must have been the kiss of death b/c when I went downstairs to listen to some music the same sub was making the noises again. Aaargh! mad.gif

Guess it may have to go into the shop after all...

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