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Official Rythmik Audio Subwoofer thread - Page 267

post #7981 of 9690
1/17/13 at 6:34pm
It sounds to me like the isolation pad "works" in the sense that it would reduce the vibration to your theoretical container of water. The question is, does that translate into an audible difference to our ears when used in the context of audio and not buckets of water?
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post #7982 of 9690
1/17/13 at 6:39pm
Quote:
Originally Posted by pyronious View Post

It sounds to me like the isolation pad "works" in the sense that it would reduce the vibration to your theoretical container of water. The question is, does that translate into an audible difference to our ears when used in the context of audio and not buckets of water?

No argument there. I agree isolation pads won't change the frequency response of your sub. However, if the vibrations are causing noises in your room and the isolation pad stops that, your system will sound much better.

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post #7983 of 9690
1/17/13 at 7:29pm
Quote:
Originally Posted by dominguez1 View Post

Cabinet panels do vibrate...
Yes, they do. But if the sub is properly designed and constructed those vibrations do not take place within the subwoofer passband, or anywhere close to it. Panel vibrations in a well made sub will occur in the midrange, in the vicinity of 500 to 1kHz. The amount of panel deflection will be on the order of a half millimeter or less, usually a lot less. That is not going to cause a floor to vibrate. But there might be some buzzing, so some type of isolation from a solid floor is a good idea, as in rubber feet, a carpet pad, whatever. With a carpeted floor the carpet provides all the isolation required.
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post #7984 of 9690
1/18/13 at 5:53am
I got the great gramma not to improve the sound quality of the FV15HP itself. My problem is my wood floors. I wanted to elimante any sub to floor contact vibrations or sub walk and save possible damage to my floor and the sub's finish. I have the floor spikes for the sub but I do not want to damage the floor. I do not have the time or desire to make my own and I wanted something that looked nice as well. The great gramma met my needs.

I did not buy the great gramma to fix rattling windows or doors or achieve better sounding sub (I already got that when I bought the FV15HP). An example, I watched Dredd and Tron Legacy back to back the other night at half sub volume and -19db on my receiver in a 15x17 room. In my one bathroom, the contents of my one shelf fell on the floor that was 17ft away from the sub in another room. Obviously the great gramma is not going to stop the actual cone vibration from displacing bass as it will still transfer from the cone to the air and thus make contact with other objects.

I will clarify my earlier recommendation to the person who asked in regards to his wood floors and the unique problems it has verses carpets. If you don't want to use floor spikes, rubber feet, don't want to build something yourself and want something that looks nice, the great gramma will fit all those needs.
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post #7985 of 9690
1/18/13 at 6:06am
Quote:
Originally Posted by Eldiablos View Post

I got the great gramma not to improve the sound quality of the FV15HP itself. My problem is my wood floors. I wanted to elimante any sub to floor contact vibrations or sub walk and save possible damage to my floor and the sub's finish.
That's fine, subs should not be placed directly on a hard floor. But a fifty plus dollar isolation gizmo isn't necessary. Rubber feet are all that's required to stop any vibration transfer. In the case of a down firing sub it will sound better if it's not firing at a hard floor, but here also a high priced accessory works no better than a few dollars worth of carpet or other resilient material.
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post #7986 of 9690
1/18/13 at 1:42pm
Quote:
Originally Posted by mikepos View Post

I'm undecided between subs and number of subs. I play moslty home theater but also music and am fussy on music reproduction. My room is 14 x 18 x 8 ft and my mains are PSB stratus gold fed by oppo95 direct to Bryston 3BST (very SPL capable combo), with Lexicon (bryston) 5ch for surround channels, no pre/pro. I play very loud music and movies and need good output. My current sub is corner loaded Hsu vtf-3mk2 and it's output hasn't failed but I have turned down the volume in load bass heavy scenes to be safe, I feel I'm pushing the spl limit. My bass response is quite uneven and I'm considering 2 subs to help fill nulls (I sit near one - length wise in room mains are 3' off front wall and I sit about 1/3 off rear wall, gives best music this way). I find the Hsu a bit boomy currently but much trial hasn;t found an even spot for it including moving seat a bit.
For single sub I'm drawn to the FV15HP but am concerned I'll still need 2 to even out the bass and adding a second is more than I want to pay. So I'm considering trying the F15 first then adding a second if needed but I'm concerned about volume for those (would probably go middle of front and back walls if I got two). My room is dedicated and sub size is not important. I hope the F15 or FV15HP will help me even out bass with the PEQ and would like to start with one unit.
I live in Canada near border and would ship to Maine but I don't want to be hit with shipping for the 30 day trial... can I expect to be happy and have headroom for the F15 (370PEQ)?
Also, is there any sound or performance difference if saving $100 with the 550PEQ3 on the FV15HP? And if I got this now and added a 2nd FV15HP with the 600PEQ3 (say no 550 left) would there be any issue matching them? I've seen a few amp issues posted lately, are these the 550 or 600W amps - please post if you're one of those with amp issues.

Lastly, can anyone compare the Hsu vtf3mk2 (same as current vtf2 but with 50W more amp) compared with the F15 370PEQ3 for SPL?
thanks.

Although corner loading typically provides the most room gain (higher max SPL) it may not be boosting all the frequencies evenly and can cause a "boomy" kind of sound. It may be worth trying a few different locations.

I love my dual FV15HP's, very clean and accurate. If you go with the Rythmik you will get a high performance quality product with great customer service.
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post #7987 of 9690
1/19/13 at 2:28pm
I've found in other forums that some people report the F15HP as being more full and punchy (i.e. chest pounding) than the F15, can anyone verify this? There may have been amp changes but one guy in particular seemd to have been careful about the same placement and settings, yet liked the sound of the HP better... he didn;t play extreme volumes either.

Also, I've come across several comments abouth the sealed F15 having more mid bass slam (due to tighter sound reportedly) than the FV15HP, given the same volume, has anyone found that?

I'm basically down to trying an F15 in my 18'x14'x8' room, and getting another if Ican't fins a more even FR than I'm getting with my corner loaded HSU vtf3mk2, which has a bad 37Hz peak (due to corner placement, but can;t find a better location so far). I'm hoping the PEQ cutting down 37Hz will help enough to be happy. But my system is very capable, good power into PSB STratus Gold mains with 9" woofers that go down strongly into low 20s in my room.

My fear is that I need high SPL and I play very loud, and watch 80/20 movies/music. I'm afraid even if I go with 2 F15s won't get the SPL I want.

I'd like to try the FV15HP to see if one sub would do for sound quality and FR evenness, but if I find I need a second sub I can't afford a second one of that price - if going to 2 subs I'm pretty much stuck with the F15 for that.

I have 3 questions:

1. can anyone give a reliable comparison in SPL output between my Hsu vtf3 mk2 and the Rythmik F15? If tha F15 is any more capable it should be fine.

2. How much midbass slam (chest thump) can I expect from the F15 vs the Hsu, which I find a bit lacking.

3. How does the F15 (or F15HP) compare to the FV15 for chest thumping, couch shaking bass?

thanks, including responses to my previous post here
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post #7988 of 9690
1/19/13 at 2:45pm
Your room is a good size, but it's not huge. The HSU VTF-15H ($879 + shipping) will give you output, extention and PEQ. If you're thinking you might need two subs, get a couple of SVS PB-1000s ($499/ea., shipped) or SB-12NSDs ($649/ea., shipped) and add a miniDSP for EQ-ing / room correction.

I have nothing against Rythmik, but there's no need to get hung up on one brand when there are other options.
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post #7989 of 9690
1/20/13 at 3:06am
What happens if i set the crossover on the F15 at 45 hz and set the PEQ at +3db at 70 hz ?
Edited by qguy - 1/20/13 at 3:15am
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post #7990 of 9690
1/20/13 at 7:45am
Quote:
Originally Posted by qguy View Post

What happens if i set the crossover on the F15 at 45 hz and set the PEQ at +3db at 70 hz ?

The end of all mankind as we know it.
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post #7991 of 9690
1/20/13 at 8:20am
Does anybody have any type of "PEQ for Dummies" walk through or anything that will help me understand how to use the PEQ on my FV15HP? I am trying to decide if I should switch from using the LFE input or the line in input so I can utilize this but I have read the the tutorial on the Rythmik page and really don't understand it. Do you need measuring equipment to use the PEQ function?
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post #7992 of 9690
1/20/13 at 9:50am
Quote:
Originally Posted by Smigro View Post

Does anybody have any type of "PEQ for Dummies" walk through or anything that will help me understand how to use the PEQ on my FV15HP? I am trying to decide if I should switch from using the LFE input or the line in input so I can utilize this but I have read the the tutorial on the Rythmik page and really don't understand it. Do you need measuring equipment to use the PEQ function?

U need to measure to know what to set the PEQ to. Basically we aim for a flat frequency response (or a house curve) but rooms don't make that easy. Subs and Speakers that measure flat in an anechoic chamber or in outside tests will not measure flat in a room. So the idea is you take measurements, find a valley and boost that valley (while setting the bandwidth to how wide the valley is) to get it back to flat. Remeasure and tweak as needed.

I don't see how you could know what to boost without measurement gear. I suppose you could do it very painfully with just an SPL meter but check out the new USB mics, you can be measuring quickly.
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post #7993 of 9690
1/20/13 at 10:06am
Quote:
Originally Posted by dstew100 View Post

U need to measure to know what to set the PEQ to. Basically we aim for a flat frequency response (or a house curve) but rooms don't make that easy. Subs and Speakers that measure flat in an anechoic chamber or in outside tests will not measure flat in a room. So the idea is you take measurements, find a valley and boost that valley (while setting the bandwidth to how wide the valley is) to get it back to flat. Remeasure and tweak as needed.

This graph of our old subwoofer drivers, in my opinion, makes for a good example of raising a specific frequency as it clearly shows a null on the right. The left side of the graph is ported radiator caused.

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post #7994 of 9690
1/20/13 at 10:39am
Quote:
Originally Posted by BeeMan458 View Post

This graph of our old subwoofer drivers, in my opinion, makes for a good example of raising a specific frequency as it clearly shows a null on the right. The left side of the graph is ported radiator caused.


I am new to this so bear with me. Looking at that I would assume you would boost it at 80, but i would also assume that is your XO point so i am not sure if that is normal. I also see that here are also nulls at 60 and 70.
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post #7995 of 9690
1/20/13 at 10:51am
Quote:
Originally Posted by Smigro View Post

I am new to this so bear with me. Looking at that I would assume you would boost it at 80, but i would also assume that is your XO point so i am not sure if that is normal. I also see that here are also nulls at 60 and 70.

Looks closer to 88Hz to me. If it is a true null it cannot be corrected via EQ though. You wind up putting a huge tax on your amp and driver for a sound you will never hear.

So I would try a shallow boost at 88 to see if it can be boosted, and I would try moving the sub around. But if it couldn't be boosted I just may do a wider boost across the entire top or attenuate the lower end. Attenuating is better than boosting. short short though it's still trial and error and listening to see which setting combination you like the most. Measuring is huge at doing this sort of thing.

The lower null around 27 would bother me too, maybe need some bass traps.

EDIT: That's in the crossover region, maybe try dropping crossover to 70 if your mains can handle it and working on the other issues.
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post #7996 of 9690
1/20/13 at 11:50am
I had the opposite problem in my system. My mains had a null around 75/80 so I am using a 90 crossover since my FV15hp didn't have any issues. It technically sounded better with a higher crossover but then I could locate the sub in the room and it was distracting so I settled for 90.

Regarding the previous discussion about isolation pads... I have tile floors on concrete in my room so I used 4 small furniture moving pads on each corner. You can purchase them at harbor freight for 3.99 right now. It works great and they are very inexpensive and you can use the larger ones for moving furniture. When I need to clean around the sub I can just slide it out of the way. If they only came in black it would be perfect.
Edited by bmonighetti - 1/20/13 at 11:57am
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post #7997 of 9690
1/20/13 at 11:56pm
Here's my take on the questions:

mikepos---You are never going to know how any particular sub is going to sound in your room, with your main speakers and your ears, until you actually have the sub in question in your room. Not the answer you want, I know. Sorry, that's just the way it is. After all the reading, and thinking, and more reading.....eventually you are just going to have to take a chance and try one. Pay for just one; if you like it, order another; if you don't, return it. True, you'll be out the cost of return shipping, but it will be worth it to educate yourself.

Smigro---Get yourself a cheap measuring mic and a Test-Tone CD ( the Stereophile one will do). Take a reading, then move the sub and do it again. Then do both again. The frequencies that are not flat in all of your readings are the room and the sub. Looking at the peaks ONLY, use the PEQ controls on your sub to bring down the worst center frequency seen on the readings. Measure again. If the offending frequency band has been corrected, congratulations, you're done. Do NOT use PEQ to boost the worst frequencies, only to cut them. NO amount of boost will correct a null. That's why it's called a null! And that is why we use PEQ for cutting only.
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post #7998 of 9690
1/21/13 at 6:27am
Quote:
Originally Posted by BDP24 View Post


Smigro---Get yourself a cheap measuring mic and a Test-Tone CD ( the Stereophile one will do). Take a reading, then move the sub and do it again. Then do both again. The frequencies that are not flat in all of your readings are the room and the sub. Looking at the peaks ONLY, use the PEQ controls on your sub to bring down the worst center frequency seen on the readings. Measure again. If the offending frequency band has been corrected, congratulations, you're done. Do NOT use PEQ to boost the worst frequencies, only to cut them. NO amount of boost will correct a null. That's why it's called a null! And that is why we use PEQ for cutting only.

Thanks for the info. I did not know that the the PEQ controls were used to cut instead in boost...good to know.

Two more questions though. What mic would you suggest and where can I get his Stereophile test-tone CD? Is this a CD that you burn or one that you buy at a store? Also, if I get a measuring mic would I also need a program like REW to do this? I only ask because I do not have a laptop ATM (hoping to get one with tax return money) so if one is needed this may be something I put off until I get a laptop. Would I be able to do just a basic spl meter to do this or are they not accurate enough for this kind of work.
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post #7999 of 9690
1/21/13 at 6:36am
Quote:
Originally Posted by Smigro View Post

Thanks for the info. I did not know that the the PEQ controls were used to cut instead in boost...good to know.

My understanding, one can do about a 3dB boost and that's about it as you're trying to sweep water uphill. Unfortunately, your choices become, move the sub, move the listening position, room placement panels or live with it. eek.gif

Quote:
Two more questions though. What mic would you suggest and where can I get his Stereophile test-tone CD? Is this a CD that you burn or one that you buy at a store? Also, if I get a measuring mic would I also need a program like REW to do this? I only ask because I do not have a laptop ATM (hoping to get one with tax return money) so if one is needed this may be something I put off until I get a laptop. Would I be able to do just a basic spl meter to do this or are they not accurate enough for this kind of work.

This is the mic I use.

Lots of choice from a wireless USB mic to calibrated mics. This mic comes with a downloadable calibration file.

A program like REW has a signal generation capability that allows you to customize your frequency sweeps. You can't do this with the Stereophile test-tone CD.

-
Edited by BeeMan458 - 1/21/13 at 7:09am
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post #8000 of 9690
1/21/13 at 7:47am
Quote:
Originally Posted by Smigro View Post

Thanks for the info. I did not know that the the PEQ controls were used to cut instead in boost...good to know.

Two more questions though. What mic would you suggest and where can I get his Stereophile test-tone CD? Is this a CD that you burn or one that you buy at a store? Also, if I get a measuring mic would I also need a program like REW to do this? I only ask because I do not have a laptop ATM (hoping to get one with tax return money) so if one is needed this may be something I put off until I get a laptop. Would I be able to do just a basic spl meter to do this or are they not accurate enough for this kind of work.

You can boost a sub SLIGHTLY with PEQ (I was exaggerating for effect!), but not if the dip in the curve is caused by a null. Boosting a room null costs you enormous amounts of amp power and driver excursion, and buys you nothing (the null eats all the power you throw at it, as the driver valiantly tries to reproduce that which the room will not allow---at least not in it's position in that room, and perhaps not at all, depending on the room). To understand acoustics better than we have space for here, get a book on the subject (Harry F. Olson wrote a good one).
The Stereophile CD is available on their website, and SPL meters are available at any good electronics store (even Guitar Center sells 'em!). For a measuring mic, look at the DSP website. They have a great Sub-EQ that measures and corrects for frequency and time-domain problems; the mic that comes with their EQ is available separately.
By the way, if you really want to EQ your sub (or your whole system), Behringer has a few different Parametric Equalizers that allow one to have a lot of PEQ frequencies, not just the one or two that are available on some of the better subs. Like yours!
Edited by BDP24 - 1/21/13 at 8:09am
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post #8001 of 9690
1/21/13 at 7:56am
Quote:
Originally Posted by BDP24 View Post

You can boost a sub SLIGHTLY with PEQ, but not if the dip in the curve is caused by a null. Boosting a room null costs you enormous amounts of amp power and driver excursion, and buys you nothing (the null eats all the power you throw at it, as the driver valiantly tries to reproduce that which the room will not allow-.
Not necessarily. So long as the amp has the power and the driver has the excursion you can fill a null using EQ. The problem is that the frequency and depth of the null will vary depending on the LP, so using EQ alone will only work within a fairly small sweet spot. If you only need smooth response in a small sweet spot that's OK, but otherwise adding one or more additional subs will work much better.
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post #8002 of 9690
1/21/13 at 8:28am
In theory, sure Bill. In this case, however, Smigro has stated that his one Rythmik sub will be his only sub for now, and we know what power the amp has and excursion the driver has.
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post #8003 of 9690
1/21/13 at 8:32am
A true null cannot be corrected with EQ, but some dips you get are not true nulls.

In addition to the Behringer parametric EQ devices the minidsp is a pretty sweet PEQ as well but also has delay controls and many other features.

I'd recommend REW, it has a signal generator so you would not need the test tone CD when using REW.

There's a USB version of the Dayton mic just linked which makes it a much simpler set-up discussed here http://www.avsforum.com/t/1449924/simplified-rew-setup-and-use-usb-mic-hdmi-connection-including-measurement-techniques-and-how-to-interpret-graphs/450 and also talks about the plug and play nature of the minidsp usb mic. Because of the individual calibration and the cal files at differing angles I'd go with the dayton even if it is a bit more hassel to get working with REW.

The REW forum at home theatre shack is good, the software's author hangs out there and is very helpful.
Edited by dstew100 - 1/21/13 at 8:39am
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post #8004 of 9690
1/21/13 at 8:53am
Quote:
Originally Posted by BDP24 View Post

Boosting a room null costs you enormous amounts of amp power and driver excursion, and buys you nothing (the null eats all the power you throw at it, as the driver valiantly tries to reproduce that which the room will not allow---at least not in it's position in that room, and perhaps not at all, depending on the room)

Sounds like the description of a starship trying to escape the clutches of a black hole.
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post #8005 of 9690
1/21/13 at 12:14pm
Received my sub this morning. Haven't watched a blu-ray yet but for music it's just killer. All my hours of research have finally paid off. Excuse the crappy pic cause I have a crappy camera. Of course I still have some spaghetti to clean up too.

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post #8006 of 9690
1/21/13 at 12:32pm
Quote:
Originally Posted by XStanleyX View Post

Received my sub this morning. Haven't watched a blu-ray yet but for music it's just killer. All my hours of research have finally paid off. Excuse the crappy pic cause I have a crappy camera. Of course I still have some spaghetti to clean up too.


Congrats Stanley.
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post #8007 of 9690
1/21/13 at 12:34pm
Quote:
Originally Posted by Prime316 View Post

Congrats Stanley.
Thanks buddy. smile.gif
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post #8008 of 9690
1/21/13 at 12:35pm
Quote:
Originally Posted by XStanleyX 
Received my sub this morning.
Congrats on the new sub. cool.gif Nice set-up...and funky walls, too! smile.gif (They kinda look like stained-glass - a very interesting effect.)
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post #8009 of 9690
1/21/13 at 12:37pm
Quote:
Originally Posted by eljaycanuck View Post

Congrats on the new sub. cool.gif Nice set-up...and funky walls, too! smile.gif (They kinda look like stained-glass - a very interesting effect.)

Thanks, it carpeting. I have it on the front and two side walls. I can do that cause I have no WAF issues. tongue.gif It's just a man cave.
Edited by XStanleyX - 1/21/13 at 12:55pm
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post #8010 of 9690
1/21/13 at 2:34pm
@XStanleyX

Schweeeet, enjoy
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