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Official Rythmik Audio Subwoofer thread - Page 338

post #10111 of 15139
Quote:
Originally Posted by Rythmik View Post

You may not realize that "decently loud" 10-15hz output is not what you expect.
+1. I routinely measure subs at 20Hz at 100dB and, were it not for the meter giving the reading, you wouldn't know there was any sound at all. This is outdoors, where you don't feel any compression, nor is there anything nearby to vibrate.
Quote:
One other common reason for lesser subs sounding "louder" is their higher distortion. Second and third harmonics at high levels will make the sub seem louder even though it is distortion because they reach into the "audible" range.
That even applies to good subs. Direct radiators create a lot of harmonic content, and the louder they're played the greater the THD. It's unavoidable, the motion of the cone is the responsible element. You can feed a sub a 20Hz tone and there will be lots of output at 40 and 60Hz, and that's what you hear, not 20Hz. I don't have that with the subs I measure, as they're folded horns, which filter out those harmonics in the bends of the horn. The only way to know what's actually present in the output is via an RTA, and the only way to know if you can really hear 20Hz and lower is to listen to a speaker capable of delivering down that low with inaduible THD at very high levels.
As for lesser subs sounding louder, the reason why is seen on an equal loudness curve. Lesser subs tend to be smaller subs, tuned to deliver maximum sensitivity between 50 and 70Hz, which is far easier to hear than 40Hz and lower. Pro-touring sound FOH engineers are well aware of this fact, and set up their systems accordingly. Even though those systems may be capable of high output from 40Hz on down, the first-in-your-chest- take-your-breath-away bass that you can get at high energy concerts doesn't come from below 40Hz, it comes from 50-70Hz. Tactile feel is a different story, that comes from 35Hz and below, but you don't hear it, you feel it, and your room has to be small enough and/or the sub count high enough to pressurize the room.
post #10112 of 15139
And an easy way to make your sub sound louder and/or get "chest thumping" bass is to use your Rythmik plate amp's PEQ to boost the frequencies mentioned by Bill, 50-70Hz. Some cynical designers build into their subs a permanent boost at those frequencies to impress novice sub buyers.
post #10113 of 15139
Quote:
Originally Posted by Bill Fitzmaurice View Post

Tactile feel is a different story, that comes from 35Hz and below, but you don't hear it, you feel it, and your room has to be small enough and/or the sub count high enough to pressurize the room.

Bill - thanks for the response. I currently have a Focal 13" sub that is nice and clean and I would say plays well to about 35Hz, which makes it great for music but underwhelming for HT. I don't want to worry or pay for another sub upgrade for a long time. I want clean and flat but I want powerful, tactile as you call it and I don't want to feel like I am missing anything like I feel with my current sub. When I first started researching, I came across the Submersive and I'm sure that one would pressurize my small (1800cuft) room with opening in back but I'd like at least two subs to even out room response.

At this point I'm considering two of the following: Submersive, JTR S1, or LMS 5400. Not because I need two but because I want even room response. If I were to go Rythmik, I would go with 3 of the DIY equivalent to the F15HP and build them as end tables. I can read tons about the other subs and how they compare to each other but I haven't really been able to make the leap that 3 Rythmik F15HPs would be equivalent to a single Submersive in depth and output. If I was able to get an affirmative statement to that question, then my search is over and I will purchase the Rythmik subs soon.

So for me I want solid, tactile output down low while still having good, but not silly output levels. And I want flat, none of this artificial boost crap. I'll use my MiniDSP mic and REW to get flat output and my guests and I will get used to accurate bass, even if the uninitiated are a little underwhelmed at first. But I also want that tactile, bring a smile to your face bass too, which the subs I mentioned above have the capability to do.

David
post #10114 of 15139
Actually, after reading this thread, it seems 3 of the FV15HPs would give similar or more output than a single Submersive but that is somewhat conjecture since I haven't even read about two FV15HPs being side by side with a Submersive.

http://www.avsforum.com/t/1447350/2500-budget-what-would-you-go-with/30#post_22761529

I'll probably still give it some thought but it looks like 3 of the DS1510 ported kits would work and be a tremendous value, all while allowing me to build the perfect size end tables, er...sub enclosures.
post #10115 of 15139
And Brian (Rythmik), thanks for a very informative post #10108. I'm looking forward to listening to some of what I've been missing but have the calibrated mic and REW software to figure it out.
post #10116 of 15139
Quote:
Originally Posted by dgage View Post

Actually, after reading this thread, it seems 3 of the FV15HPs would give similar or more output than a single Submersive but that is somewhat conjecture since I haven't even read about two FV15HPs being side by side with a Submersive.

Before we get into the discussion of SPL comparison, we need to understand one thing about ported subs. At 1.4 times the box tuning frequency, the output from the woofer and the vent is about the same. That means it acts as if there are two woofers in the system at the frequency. For FV15HP 2 port mode, 1.4 times the box tuning frequency is about 25hz. Below 1.4 times the box tuning frequency, the vent output, relative to woofer output begin to increase, but still it has substantial.

So the short answer to your question is it is more like 1.5 FV15HP would give similar output than a single submsersive at the low end and 2 FV15HP to one submersive at higher frequency. In terms of power rating, that is just as elusive as SPL comparison based on published data from the manufacturers. For power amplifiers based on switch mode power supllier, 240V mode will have higher output than 120V mode. So you can ask if the rated power is based on 120V or 240V.

-
Edited by Rythmik - 8/6/13 at 5:19am
post #10117 of 15139
Okay so I think I need some help setting up my dual LV12R's. What is the best way to EQ them so that the phase and output match? They are currently located inside each of my towers and are equidistant from the main listening position. I have the gain on each sub set to 12 o'clock and they are hooked up to the receiver using a splitter. My Denon can only EQ one sub. I ran Audyssey and listened to the receivers test tones at the main listening position and my rat shack SPL meter showed the same reading for both subs. About 90db! I guess after doing this and listening to a scene from the Dark Knight I was expecting more since my single LV12R used to rock. I tried the below method I got from another post! Is this accurate because after I followed it and ran Audyssey it boosted the sub channel to like +8 dbs. According to the instructions below it shouldn't have done this, but I followed the instructions to the "T".

1. Pick a spot in the center of your room away from the walls.
2. Move the first sub to that spot, and connect the audio and power cables.
3. Place the SPL meter immediately in front of the sub's cone, at a distance of 1-2 inches, centered on the cone.
4. Mark the position of the sub (using masking tape is a good way).
5. Run the sub channel level-setting tone from the AVR and adjust the sub's gain to the desired level (I use 90 dB).
6. Being very careful not to disturb the SPL meter's position, remove the first sub and replace it with the second sub. Make sure it is lined up exactly as the first sub with respect to the SPL.
7. Running the AVR test tone, adjust the second sub's gain to match the first sub's (90 dB).
8. Place the two subs back in the position you want them to be.
9. Run Audyssey room correction (a critical step, IMO, otherwise you aren't correcting for room issues).
10. Observe what trim level Audyssey sets in the AVR. Ideally, it should be in the -3 to +3 dB range. If it is too far towards either limit, go back to step 5 and use either a lower or higher target gain level, depending on your final results.
11. If the trim levels set by Audyssey are different for the two subs, then they are no longer gain-matched. To re-establish the gain-matched status, take 1/2 of the difference in trim levels, add it to the sub with lowest trim, and subtract it from the highest sub trim. Now the subs are gain-matched once again.

By using this procedure, you will ensure that both subs are outputting at the same level. Want to give it a try? (Obviously I like typing more than HTG...)

Edit: This procedure is designed for identical subs.
Edit 2: Steps 1-8 can be used even if you don't have an AVR with Audyssey (e.g. MCACC).
post #10118 of 15139
Those positions for the subs may not be the best for low bass reproduction in the room. And does it sound worse with the second sub, or just not as big an improvement as you were expecting? To get a lot more bass, you need to co-locate them in the same spot/corner. Otherwise placing them in different locations in the room is good for smoothing out response (if done correctly, measured, etc.).

Can you try corners / along a wall 1-2 feet away from a corner? Or nearfield, like next to or behind your listening position? Maybe one behind the couch and one up front? Putting one or both subs nearfield will provide a lot of tactile feel to the bass as well, not to mention getting more volume out of it. But setting up dual subs can be very tricky.
post #10119 of 15139
^^^turn off one sub, run test tone again to see what spl meter reading. Write down the number then turn on both sub, run test tone again. SPLmeter should read 4db to 6db higher than the number you write down.
post #10120 of 15139
It sounds worse with the second sub. I can definitely try stacking them, but it might look a little funny. Right now one sub is in a corner and the other is at the end of the same wall that opens up to the kitchen. I guess I was more or less curious if the method I got from the other post was an accurate way to eq dual subs.
post #10121 of 15139
*^^^ I have dual FV15hp and the way I set them up was almost similar to you. The only different was I set one sub and run Audyssey first to the point where my AVR at 0 and my SPL reading for my sub at 68db. Then I took that sub out put in center of the room, mark it, run test tone, write down SPL number and do the second one at exactly same spot and match it level to the SPL reading of first sub. After that I put both sub in their prime position (very similar to your lay out, both sub in front corners next to my main, one side open up to my dinning room) run test tone and Audyssey. and my SPL reading is at around 74db and my AVR is at 0.

FYI, I set both sub's phase is at 0
post #10122 of 15139
Wow just stacked them and it yielded a pretty substantial increase in output. They are not even stacked in the corner either. I'm a little scared to put them in the corner considering after moving into my apartment I got a noise complaint with just one hooked up and turned pretty far down.
post #10123 of 15139
Quote:
Originally Posted by JT78681 View Post

It sounds worse with the second sub. I can definitely try stacking them, but it might look a little funny. Right now one sub is in a corner and the other is at the end of the same wall that opens up to the kitchen. I guess I was more or less curious if the method I got from the other post was an accurate way to eq dual subs.

This a method that I have used with multiple sub and is a very solid setup: http://forum.blu-ray.com/showthread.php?t=95817
You don't have to read the whole thing but, you will get a better grip on what is happening if you do. The pertinent part is near the bottom of the page. Good luck.
post #10124 of 15139
smile.gif I have stumbled across this and read it. I guess maybe I was just looking for an easy way of doing this and taking my approach is not going to leave me with the best results. Gonna have to read it again!
post #10125 of 15139
Quote:
Originally Posted by dgage View Post

Actually, after reading this thread, it seems 3 of the FV15HPs would give similar or more output than a single Submersive but that is somewhat conjecture since I haven't even read about two FV15HPs being side by side with a Submersive.

http://www.avsforum.com/t/1447350/2500-budget-what-would-you-go-with/30#post_22761529

I'll probably still give it some thought but it looks like 3 of the DS1510 ported kits would work and be a tremendous value, all while allowing me to build the perfect size end tables, er...sub enclosures.

 

Quote:
Originally Posted by Rythmik View Post


Before we get into the discussion of SPL comparison, we need to understand one thing about ported subs. At 1.4 times the box tuning frequency, the output from the woofer and the vent is about the same. That means it acts as if there are two woofers in the system at the frequency. For FV15HP 2 port mode, 1.4 times the box tuning frequency is about 25hz. Below 1.4 times the box tuning frequency, the vent output, relative to woofer output begin to increase, but still it has substantial.

So the short answer to your question is it is more like 1.5 FV15HP would give similar output than a single submsersive at the low end and 2 FV15HP to one submersive at higher frequency. In terms of power rating, that is just as elusive as SPL comparison based on published data from the manufacturers. For power amplifiers based on switch mode power supllier, 240V mode will have higher output than 120V mode. So you can ask if the rated power is based on 120V or 240V.

-

Thanks Brian, but I think you are being modest. :)

 

I guess it depends what you mean by 'low' end. My bet would be the FV15HP would have more output from 12.5hz to 20hz than the submersive.

 

The below is from data-bass and compares the Dayton RS-18HO sealed sub compared to the FV15HP in 1 port mode:

 

 

My guess would be that 2 Dayton 18's dual opposed would be more output than the 1 submersive. If you look at the above, and add 6dbs on the Dayton from 12.5hz-20hz (to simulate dual opposed), the FV15HP still has more output that the two Dayton 18's. At probably 30hz and up, yes, you would likely need 2 FV15HP's to match the submersive.

 

Of course, max SPL is just a by-product of your great design. SQ is also where it shines. :)

post #10126 of 15139
Does rythmik have an email address? I can't find one on their website.. Thanks
post #10127 of 15139
Quote:
SQ is also where it shines. smile.gif


One unfortunate thing that happens a lot here on the forums (especially the sub forums) is that people get caught up in numbers and charts --1 of sub X equaling 2 of sub Y and what will provide the most bass -- and overlook the sound quality part of the equation (in both the sub and the setup/room treatment). It's inevitable for a variety of reasons, but still unfortunate. Hearing live the difference between good, clean bass and sloppy bass can be pretty shocking. As can adding a few hundred dollars worth of bass traps, or moving your sub to a different part of the room and getting a completely different result. I enjoy seeing/reading discussions about not just the numbers and SPL, but the quality and clarity of the bass. Anyway, just glad to see SQ brought up. smile.gif
post #10128 of 15139
Quote:
Originally Posted by gigging View Post

Does rythmik have an email address? I can't find one on their website.. Thanks

 

http://www.rythmikaudio.com/contact.html

post #10129 of 15139
Quote:
Originally Posted by dominguez1 View Post

Thanks Brian, but I think you are being modest. smile.gif

I guess it depends what you mean by 'low' end. My bet would be the FV15HP would have more output from 12.5hz to 20hz than the submersive.

The below is from data-bass and compares the Dayton RS-18HO sealed sub compared to the FV15HP in 1 port mode:




My guess would be that 2 Dayton 18's dual opposed would be more output than the 1 submersive. If you look at the above, and add 6dbs on the Dayton from 12.5hz-20hz (to simulate dual opposed), the FV15HP still has more output that the two Dayton 18's. At probably 30hz and up, yes, you would likely need 2 FV15HP's to match the submersive.

Of course, max SPL is just a by-product of your great design. SQ is also where it shines. smile.gif
[/quote/]

That totally makes me want the fv15hp even more now!
post #10130 of 15139
Quote:
Originally Posted by gigging View Post

Does rythmik have an email address? I can't find one on their website.. Thanks

Also you can contact me at tech@rythmikaudio.com
post #10131 of 15139
Quote:
Originally Posted by cyberbri View Post

One unfortunate thing that happens a lot here on the forums (especially the sub forums) is that people get caught up in numbers and charts --1 of sub X equaling 2 of sub Y and what will provide the most bass -- and overlook the sound quality part of the equation.

Actually, sound quality is the main reason I am looking at Rythmik and based on the reviews I've read, sound qualtiy is universally lauded. So it's not that I and I would assume others are skipping it because we don't care about SQ, we are bypassing it since it is a given. The only question then is does the Rythmik have enough output, whatever enough is. For me, based on the responses I think it will but I may never be able to compare my soon to be purchased Rythmik DIY subs to a Submersive (one of the bench mark subs at the GTGs). Once I set them up well in my own room, I'm sure I won't even care. But in the research phase, especially for an ID purchase, the comparison is valid. That's my $.02.

And thanks for the numbers Dominguez1. Not sure I'd jump to the conclusion that one FV15HP would have more output between 12-20 Hz than a Submersive although it might (wish we had true comparative numbers). However, there is a price difference and the fact that the two are so close gives me confidence that my 3 DIY FV15HP will be the last subs I need for a long, long time...I hope.
post #10132 of 15139
I may be mistaken, but the HP sealed subs should have more output below the FVHP's tuning frequency than it does. Higher SQ too.
post #10133 of 15139
Quote:
Originally Posted by BDP24 View Post

I may be mistaken, but the HP sealed subs should have more output below the FVHP's tuning frequency than it does. Higher SQ too.

well being the FV15HP digs to 12.5hz with authority, how often would you actually utilize any output below that tuning point? Sealed does not automatically mean better sound quality...thats a myth. Both designs have thier pros and cons depending on how they are used. Ported dubs shine in large rooms that have a open floor plan, sealed subs shine in small to medium size rooms that are sealed off.
post #10134 of 15139
Quote:
Originally Posted by BDP24 View Post

I may be mistaken, but the HP sealed subs should have more output below the FVHP's tuning frequency than it does. Higher SQ too.

If you're talking the FV15HP in 2-port mode then maybe but in 1-port mode I doubt it would as sealed subs have a natural roll-off usually starting around 25-30 Hz as a (very) generality. This is why Rythmik recommends the F15HP for music on the website and the FV15HP for home theater. Music rarely has content below 25-30Hz while movies regularly have content in the teens. And I agree with basshead81 that being able to identify a (quality) subwoofer as sealed or ported has been shown at numerous GTG (AVS subwoofer get togethers) to be a myth.
post #10135 of 15139
And Brian or Enrico, if you see this can you go over to the DIY thread (http://www.avsforum.com/forum/newestpost/1238757) and answer my question about the DS1510 in a down firing configuration? Thanks.

David
post #10136 of 15139
Quote:
Originally Posted by dgage View Post

If you're talking the FV15HP in 2-port mode then maybe but in 1-port mode I doubt it would as sealed subs have a natural roll-off usually starting around 25-30 Hz as a (very) generality.

The point being made was that the roll-off of a ported sub below the tuning frequency is steeper than the roll-off of a similar sealed sub in the same frequency range. Just look at the max output curves that Brian had posted here.
post #10137 of 15139
Quote:
Originally Posted by dgage View Post

And Brian or Enrico, if you see this can you go over to the DIY thread (http://www.avsforum.com/forum/newestpost/1238757) and answer my question about the DS1510 in a down firing configuration? Thanks.

David

This has been posted / discussed prior by Rythmik.

Two issues that both can be remedied - you mentioned both by the way. :-)

The weight of the driver requires more the just the supplied screws. Large drivers configured in down firing applications have known to "fall out." I know even though front firing most use some form of nut/bolt arrangement - my two are nice and secure via hurricane nuts and good fasteners. Ensuring you are mounted to at minimum the full thickness of a 3/4 inch or more board is a must as well. Second was the possibility given the output etc of the 1510 kit, the sub could jump off the ground. I can't speak from experience but I know my finished 4 cubic ft subs weigh in over 100 lbs each. I can't imagine them launching themselves if down fired yet nothing a little sand/weight couldn't control.
post #10138 of 15139
Kisakuku - Thanks for the graph as you are correct but it happens at ~8 Hz and so far down the curve (low DB) that there is hardly any output from one sub.

KJSmitty - I saw it discussed before (maybe one of your posts) but I didn't see it come from Rythmik and was just verifying the reasons before I go get excited and design my down firing subwoofer end tables. Thanks.
post #10139 of 15139
Quote:
Originally Posted by dgage View Post

KJSmitty - I saw it discussed before (maybe one of your posts) but I didn't see it come from Rythmik and was just verifying the reasons before I go get excited and design my down firing subwoofer end tables. Thanks.

Fully understand. I initially was going to build two down firing as well for mid side wall placements but ended up identifying (via sub-crawl) two other placement locations thus went front firing.

For Ref, one of the Rythmik responses to this question is a handful above yours in the build thread.

I was going to incorporate 2-3 inch legs/feet on my end table design and couldn't imagine they would jump but depending on the weight, I'm sure they could.. biggrin.gif

Keep us posted in the build thread!

Cheers
post #10140 of 15139
Thanks for pointing that out KJSmitty as I guess I overlooked that one.

Regarding mine, I may actually use concrete in between a box within a box construction. And will likely add a concrete or granite top...so weight shouldn't be a problem. smile.gif Yes, I over engineer stuff.
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