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Official Rythmik Audio Subwoofer thread - Page 348

post #10411 of 15117
Quote:
Originally Posted by 3db View Post

That will work for a rectangular room but not with rooms with openings or odd shapes.
It will work with parallel walls, which is why I suggested lees23 place the subs on the front & back walls of his room rather than place them on the left & right walls (which are full of openings).
post #10412 of 15117
Quote:
Originally Posted by mpalmieri1203 View Post

Ok so I could buy the amp and driver 1510 combo directly from Ryhmik. I'm having difficulty making sense of which enclosure would work with the driver and amp though. Do the interior of the enclosures need to be lined with anything in particular? I've been in audio for awhile but I've honestly never thought of putting together my own speaker.

Would this work?

http://www.diysoundgroup.com/subwoofer-flatpacks-2/4-sub-flat-pack.html

Would I really get the same sound quality by DIY than purchasing a direct build? Seems like I would save a pretty penny going this route making two even easier.

Quote:
Originally Posted by mpalmieri1203 View Post

I honestly think I might buy two flat packs cut for the Dayton RS and two kits from Rythmik and throw them together. Seems like a huge savings while providing the same if not better outcome.

So a few more questions:

1) How do I put some feet(rubber preferably) on the bottom of one of the flat packs?

2) The amp itself does the bracing get in the way or does it not go that far into the box?

3) Any suggestions or links to info on how to finish the box?


An again a tremendous thank you to those of you who have provided a lot of useful feedback.

David already gave you lots of good info, but here's some more. The 3 and 4 cu.ft. boxes that Parts Express sells they get from Erich at DIY Soundgroup, and Erich sells them cheaper. The 4 cu.ft. box is listed with cutouts for 18" drivers only, but Erich is known to have made custom baffles for people. If he can't, you could get one made locally from a small cabinet shop. The polyfill with which to line the cabinet interiors is included in the Rythmik kit. Putting together the Soundgroup flatpacks is pretty easy even if you've never before done any woodworking, but you'll need some 24" clamps to hold the boxes together while the glue dries (or use countersunk screws and fill in the holes with wood putty). The bracing in the flatpack boxes IS in the way of mounting the plate amp, but you simply cut that part of the brace off. You'll get to finish the cabs any way you like, which is great. Paint and veneer are the most common. The AVS website has a lot of sub builds you can look at, and you can use any or all the ideas you see other people displaying. I spent almost a year looking at all the builds before starting mine (I'm a patient guy!). The Rythmik DIY site has some good builds that will help you out. As for feet, Parts Express offers a lot of rubber feet, and also some great spiked feet for carpeted rooms. If it all seems like too much, just get a built sub from Brian. There's only a small difference between a 3 cu.ft. box and a 4 cu.ft. one. But a kit is cheaper, and you might end up having fun designing your own enclosure---I sure have!
Edited by BDP24 - 8/28/13 at 2:48am
post #10413 of 15117
Quote:
Originally Posted by sdurani View Post

It will work with parallel walls, which is why I suggested lees23 place the subs on the front & back walls of his room rather than place them on the left & right walls (which are full of openings).

So you are referring to the walls at the top and bottom(the long walls) of the sketch, perpendicular the the TV wall, correct?
post #10414 of 15117
Quote:
Originally Posted by sdurani View Post

The "penalty" he's talking about seems to be output, though he admits that it will "even out the room response". Which is not quite the "its hard to get them set up right" comment you attributed to him earlier.

The quality vs quantity trade-off comes down to personal preference, so you have to decide whether you want smoother bass or louder bass.

Yes, my main consideration is output. Mid wall placement is good to deal with room mode. But it comes with a price, the output is 3-5db less than a corner loaded sub. Our standard recommendation for sub placement is corner. There are some subs that are borderline boomy. Corner placement will further exacerbate the problem. Mid wall placment can sound better because it takes some energy away from the bottom end to make it sound less boomy. The sound quality from the subs does not change because we change placement. On the other hand, our subs are more articulate and we can take advantage of corner loading. In addition, very often the corner is also close to the front speakers, which makes the time alignment and coherence better than say mid wall placement of side walls.

The room mode is a problem with static/stationary signals. The so-called peak in frequency domain is not really a peak, instead, it is a ring that spreads out in time domain. When you have, say, a contant 20hz, the reverberation accumulates and that is how you get the peak and null. But when the signal is constantly changing, the reverberation is often heard later when the speaker signal already changes to a different frequency. The reverberation of the latter will arrive even later. So at any given moment, what we hear is not same as FFT (which is the mathematics giving us the frequency response). A lot of FFT are looking at 100ms or even longer time window. A better metric should really be a windowed FFT, in which we only look at say 30ms at a time. Why 30ms, that is about the time we cannot differentiate the signal arrival time.

-
Edited by Rythmik - 8/28/13 at 6:58am
post #10415 of 15117
Brian, can you speak any to your IB option? Although it probably belongs in the DIY thread it would be nice to get some more information on this. Thanks.
post #10416 of 15117
^^^

I have to admit IB is not our strong forte as we only offer 12" drivers. But customers can still benefit from the reduced mechanical distortion from spider and surround. In fact, the improvement in IB is even bigger than sealed or ported becasue there is no box spring to linearize the spring system.
post #10417 of 15117
Quote:
Originally Posted by lees23 View Post

Quote:
Originally Posted by sdurani View Post

It will work with parallel walls, which is why I suggested lees23 place the subs on the front & back walls of his room rather than place them on the left & right walls (which are full of openings).
So you are referring to the walls at the top and bottom(the long walls) of the sketch, perpendicular the the TV wall, correct?
No, by "front & back walls" I meant: front wall = TV wall, back wall = opposite the TV wall.
post #10418 of 15117
Quote:
Originally Posted by sdurani View Post

No, by "front & back walls" I meant: front wall = TV wall, back wall = opposite the TV wall.
It seems a little silly to me to have a sub 29' away from the TV in a separate area. This is not a theater room. TV room on one side, bar area and maybe pool on the other end. My goal is not to fill the entire 18'x29' foot with equal bass response.
post #10419 of 15117
Quote:
Originally Posted by lees23 View Post

It seems a little silly to me to have a sub 29' away from the TV in a separate area. This is not a theater room. TV room on one side, bar area and maybe pool on the other end. My goal is not to fill the entire 18'x29' foot with equal bass response.

I have a U shaped room with my HT in one of the "arms" of the U Because of my iregular shaped room, I ended up doing a bass crawl and found the location for teh sub to be right behind my seating position.
post #10420 of 15117
Quote:
Originally Posted by lees23 View Post

It seems a little silly to me to have a sub 29' away from the TV in a separate area.
If you find the notion of smoother bass "silly", then don't do it. Like I said, I was merely explaining what 2 subs can do that a single sub cannot. It doesn't mean you have to take advantage of those benefits.
Quote:
Originally Posted by lees23 View Post

This is not a theater room.
It is where your home theatre is.
Quote:
Originally Posted by lees23 View Post

My goal is not to fill the entire 18'x29' foot with equal bass response.
There is no way to corral the improved bass response to stay in only one area of an open space. A 20Hz bass wave is 57' long. It's going fill the entire 29' length of your room. It doesn't care whether that's your "goal" or not.
post #10421 of 15117
Quote:
Originally Posted by 3db View Post

Quote:
Originally Posted by DonH50 View Post

I disagree that the sub crawl is better than measurements, or even all that effective in many cases. Your ears are easily fooled, and subwoofer frequencies are sub-audible so you are very likely to find a point that emphasizes frequencies you hear as louder rather than the best spot for the smoothest and deepest overall response.
Good luck finding bass in a room based on measurements when one doesn't even know if one standing in null or peak.

??? What does "finding bass in a room" mean? If it means what I think you mean, just move the mic around the room to assess the response at various points. Or, in this case, place the mic at the listening position and move the sub around (or adjust the knobs, whatever) for the smoothest response. The response graph will tell you if you are in a peak or a null, and at what frequency(ies), with much finer resolution and accuracy than your ears. At least my ears and my measurement system, yours' may be quite different. Even when doing the crawl I prefer to place the sub at the LP and measure at various points instead of relying on hearing -- too easily fooled, not enough resolution, especially in the deep bass region. If you can read the graph, you can tell if you are in a peak or null.

All IMO - Don
post #10422 of 15117
Quote:
Originally Posted by DonH50 View Post

??? What does "finding bass in a room" mean? If it means what I think you mean, just move the mic around the room to assess the response at various points. Or, in this case, place the mic at the listening position and move the sub around (or adjust the knobs, whatever) for the smoothest response. The response graph will tell you if you are in a peak or a null, and at what frequency(ies), with much finer resolution and accuracy than your ears. At least my ears and my measurement system, yours' may be quite different. Even when doing the crawl I prefer to place the sub at the LP and measure at various points instead of relying on hearing -- too easily fooled, not enough resolution, especially in the deep bass region. If you can read the graph, you can tell if you are in a peak or null.

All IMO - Don

The bass crawl always puts the sub at the listener position and one crawls along the room listening whether or not your your at a null or peak. Its pretty easy to detect a null or peak in bass just by using one's ear. If you want to get fancy, bring an SPL meter along with you during the crawl. Either way, my ears have always given me enough accuracy to place the sub for optimum performance. smile.gif
post #10423 of 15117
Quote:
The bass crawl always puts the sub at the listener position and one crawls along the room listening whether or not your your at a null or peak. Its pretty easy to detect a null or peak in bass just by using one's ear. If you want to get fancy, bring an SPL meter along with you during the crawl. Either way, my ears have always given me enough accuracy to place the sub for optimum performance. smile.gif

That is still not accurate. If you use pink noise during bass crawl; that is usually 40Hz-80Hz band limited noise. What happens beyond these frquencies; you don't know. If you use music for the same; you must be locking onto specific constant frequencies e.g. kick drum or other synthesized one note bass.
post #10424 of 15117
Quote:
Originally Posted by braveheart123 View Post

That is still not accurate. If you use pink noise during bass crawl; that is usually 40Hz-80Hz band limited noise. What happens beyond these frquencies; you don't know. If you use music for the same; you must be locking onto specific constant frequencies e.g. kick drum or other synthesized one note bass.

I've created a test track on a CD that plays a 30 Hz signal which is at the bottom end of my sub's limit. You're correct that that I don't know about the other frequencies but I don't care either. I optimized my location for extension and that's the compromise I'm willing to live with. Even at that location, my sub is far from boomy and does quite well with music. smile.gif If one is using measurements to place a sub at a position, there is still a compromise with respect to frequency response.
post #10425 of 15117
Quote:
I've created a test track on a CD that plays a 30 Hz signal which is at the bottom end of my sub's limit.

If I read you correctly, you play a 30Hz sine wave during the bass crawl and it sounds at its loudest behind your couch; hence you place your sub there. And you think that's the best method for you? I cannot disagree more if it sounds best to you. Happy listening.
post #10426 of 15117
Therein is the crux of the matter. If you have a very specific idea of how you want your bottom end to sound, doing a sub crawl test may be more time efficient in getting what you want than trying to figure out what the frequency response plot should look like in order to suit your taste.

On the other hand, if smooth response is your goal (as it is for most of us around here) I have to imagine that in virtually every case it is much easier and more reliable to do it by measurements than by ear. And that would be especially true if you have more than one sub. I don't think the sub crawl method would work at all for multiple subs unless you colocate them.
post #10427 of 15117
Quote:
Originally Posted by DonH50 View Post

??? What does "finding bass in a room" mean? If it means what I think you mean, just move the mic around the room to assess the response at various points. Or, in this case, place the mic at the listening position and move the sub around (or adjust the knobs, whatever) for the smoothest response. The response graph will tell you if you are in a peak or a null, and at what frequency(ies), with much finer resolution and accuracy than your ears. At least my ears and my measurement system, yours' may be quite different. Even when doing the crawl I prefer to place the sub at the LP and measure at various points instead of relying on hearing -- too easily fooled, not enough resolution, especially in the deep bass region. If you can read the graph, you can tell if you are in a peak or null.

All IMO - Don
That's what I did .........in a sense. I have no mic or software in my mostly analog room so I instead placed my spl meter at the LP and played sine waves that ran from 10 hz and up topping out at 80 hz which is where I have everything crossed. Yeah, it was tedious as for each position I would play the sine waves, write down the results, change settings on the sub, play sine waves again, move the sub a couple feet and repeat. It pretty much took me all day one Sunday but I did find the optimum location for my FV15HP and have a fairly flat curve considering I'm using one sub with no room correction.
post #10428 of 15117
I'm very excited to be joining in on the fun. I spoke to Brian and Enrico on the phone last night and confirmed that we're still looking at November for an FV15HP in anything other than piano black which carries a premium price. I was debating pulling the trigger on a LV12R and received great input from both Brian and Enrico. I have a 15 x 15 room which has a large opening to another 15 x 15 room and Brian indicated that the LV12R would probably be sufficient at -10 from reference levels which is my normal listening volume but for reference volume I'd probably be better off with the FV15HP. Enrico was pretty much FV15HP all the way. I really appreciate the time and advice both had to offer. I was just about to pull the trigger on the LV12R because I just didn't want to wait and decided to contact Polizzio on this thread again regarding his mildly used FV15HP and give that one last go before placing my order for the LV12R. I'm super excited that we were able to come to an agreement and I should have an FV15HP here next week. Woohoo!!! I know this is the right call because if I did get the LV12R I'd always be wondering if I was missing something. I'd forever be chasing message boards to see if I should upgrade again (it's a sickness I know). So I spent a few more dollars than the LV12R but I believe my upgraditis will be cured for the foreseeable future!

My current sub is a HSU TN1225 which is a vertical cylinder design and has actually served me quite well. I can't wait to see what this sub upgrade does for my sound and will report back to this forum with my impressions. I'm upgrading my entire system and feel like a kid on Christmas morning. Components ordered below:
Rythmik FV15HP
Ascend Towers
Ascend Horizon center with RAAL upgrade
Ascend CBM 170 surrounds
Denon AVR - X4000 Amp with XT32 goodness
Panasonic TC-P60VT60 plasma display

Okay so now I'm poor but who needs money after you've already accomplished your home theater goals:)

I look forward to sharing my experiences as I get this this set up.
post #10429 of 15117
Congrats Chris, you will own one fine subwoofer. I will miss my FV15HP......Brian engineers and builds great subs. You're gonna be very happy when you get your new system all sorted out smile.gif
post #10430 of 15117
Why wait till November, when you can get it now at a discounted price smile.gif At least with the FV15HP, there would be no more "WHAT IF ?" questions going inside your brain..

Congrats
post #10431 of 15117
Quote:
Originally Posted by mchrisbrown View Post

I'm very excited to be joining in on the fun. I spoke to Brian and Enrico on the phone last night and confirmed that we're still looking at November for an FV15HP in anything other than piano black which carries a premium price. I was debating pulling the trigger on a LV12R and received great input from both Brian and Enrico. I have a 15 x 15 room which has a large opening to another 15 x 15 room and Brian indicated that the LV12R would probably be sufficient at -10 from reference levels which is my normal listening volume but for reference volume I'd probably be better off with the FV15HP. Enrico was pretty much FV15HP all the way. I really appreciate the time and advice both had to offer. I was just about to pull the trigger on the LV12R because I just didn't want to wait and decided to contact Polizzio on this thread again regarding his mildly used FV15HP and give that one last go before placing my order for the LV12R. I'm super excited that we were able to come to an agreement and I should have an FV15HP here next week. Woohoo!!! I know this is the right call because if I did get the LV12R I'd always be wondering if I was missing something. I'd forever be chasing message boards to see if I should upgrade again (it's a sickness I know). So I spent a few more dollars than the LV12R but I believe my upgraditis will be cured for the foreseeable future!

My current sub is a HSU TN1225 which is a vertical cylinder design and has actually served me quite well. I can't wait to see what this sub upgrade does for my sound and will report back to this forum with my impressions. I'm upgrading my entire system and feel like a kid on Christmas morning. Components ordered below:
Rythmik FV15HP
Ascend Towers
Ascend Horizon center with RAAL upgrade
Ascend CBM 170 surrounds
Denon AVR - X4000 Amp with XT32 goodness
Panasonic TC-P60VT60 plasma display

Okay so now I'm poor but who needs money after you've already accomplished your home theater goals:)

I look forward to sharing my experiences as I get this this set up.
Congrats, especially for the awesome price from Polizzio. One member here (Newc33?) just added the fv15hp to his lv12r. No more 'what if' question. Enjoy.
post #10432 of 15117
Quote:
Originally Posted by Cowboys View Post

Congrats, especially for the awesome price from Polizzio. One member here (Newc33?) just added the fv15hp to his lv12r. No more 'what if' question. Enjoy.

I haven't added it yet but I'm going to in about 2-3 weeks. I'm very excited!

I think maybe even buy 2 eventually but who knows... the combo between the lv12r and fv15hp might be more than enough:)
post #10433 of 15117
If anyone else is looking to sell their FV15HP for what Polizzio was asking let me know.
post #10434 of 15117
Would I have to worry about cracking my drywall up if I were to run all 3 subs? My room is 2400 cf. All enclosed besides one 7 foot opening to kitchen which is prolly about 3500cf
post #10435 of 15117
Quote:
Originally Posted by BB1111 View Post

If anyone else is looking to sell their FV15HP for what Polizzio was asking let me know.

xstanelyx is...900.00
post #10436 of 15117
Quote:
Originally Posted by basshead81 View Post

xstanelyx is...900.00

He said his isn't available anymore.

I'll try PMing him
post #10437 of 15117
I was intrigued by the infinite baffle option that BDP24 referenced as I wasn't familiar with an IB option for Rythmik. So I looked into it and here is what I found: It looks like the Rythmik's IB offering is based on the GR subwoofers with the largest option being a 12". There is a version of the GR 12" that is 16 ohms and I saw mention of 2 or 3 going on a single Rythmik 370 amp. Low end extension looks to be in the 20 Hz range but I couldn't find a frequency response graph. Since these are the paper cones, and not the normal Ryhtmik aluminum cone, the GR 12" subs go up to about 100 Hz and maybe even higher, which might be valuable for those with smaller book shelf or similar speakers.

Question for Brian - Can 4 of the GR SW12-16FRs be put on one of your amps or is 3 the limit? What about on the 400w or dual 400w amps? And what do you think the low end extension would be on 4 or even 8 GR 12s in an infinite baffle configuration? Thanks.

David
post #10438 of 15117

 

Quote:
Originally Posted by BB1111 View Post


He said his isn't available anymore.

I'll try PMing him

 

Yep, I did a trade for it so it's long gone. Wish I could have kept it. Hell of a sub.

post #10439 of 15117
Quote:
Originally Posted by 3db View Post

The bass crawl always puts the sub at the listener position and one crawls along the room listening whether or not your your at a null or peak. Its pretty easy to detect a null or peak in bass just by using one's ear. If you want to get fancy, bring an SPL meter along with you during the crawl. Either way, my ears have always given me enough accuracy to place the sub for optimum performance. smile.gif

You miss a lot of frequency content that way. What sounds loudest may not give you the best overall response. If you think it is more accurate than using a measuring system, that's fine, but I think it's not nearly as accurate.

BTW, I do not use an SPL meter for this, I use an earthworks measurement mic, preamp, and R+D SW on my notebook.

Whatever - Don
post #10440 of 15117
Quote:
Originally Posted by Torqdog View Post

Quote:
Originally Posted by DonH50 View Post

??? What does "finding bass in a room" mean? If it means what I think you mean, just move the mic around the room to assess the response at various points. Or, in this case, place the mic at the listening position and move the sub around (or adjust the knobs, whatever) for the smoothest response. The response graph will tell you if you are in a peak or a null, and at what frequency(ies), with much finer resolution and accuracy than your ears. At least my ears and my measurement system, yours' may be quite different. Even when doing the crawl I prefer to place the sub at the LP and measure at various points instead of relying on hearing -- too easily fooled, not enough resolution, especially in the deep bass region. If you can read the graph, you can tell if you are in a peak or null.

All IMO - Don
That's what I did .........in a sense. I have no mic or software in my mostly analog room so I instead placed my spl meter at the LP and played sine waves that ran from 10 hz and up topping out at 80 hz which is where I have everything crossed. Yeah, it was tedious as for each position I would play the sine waves, write down the results, change settings on the sub, play sine waves again, move the sub a couple feet and repeat. It pretty much took me all day one Sunday but I did find the optimum location for my FV15HP and have a fairly flat curve considering I'm using one sub with no room correction.

Tedious indeed! It was that sort of thing that led me to getting a mic and software. You are one dedicated 'phile!

Wonder how many here have used one of the old-school analog paper chart recorders to graph their response? Way outdated but still brings back fond memories... Something about seeing the pen squiggle out the line is just so cool. smile.gif
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