Official Rythmik Audio DIY Subwoofer Kit thread - Page 7

In the attachment you can see the difference compared to both drivers running as a direct radiator.

Shown as 1w sensitivity for each and then max SPL for each based on amp and xmax limits. Simulated in hornresp in half space then exported into REW.

12 dB higher SPL @ 20 Hz! (compared to a sealed box)
This increases to 14 db @ 26 Hz then reduces to about 9 dB @ 40 Hz, the intended crossover point.

Paul have you had a chance to take some real measurements yet? I'd like to see how it performs in the real world. I also haven't forgotten about that third article looking forward to reading it.

Part 3 is almost done and is coming out very soon.

No measurements to show just yet

I know you've been listening to it, are you happy with it? Does it meet your expectaction. I thought about building a folded horn out of a sub I have connected to the TV just for fun but after modelling it it won't work it's a very cheap speaker. Maybe sometime in the future I'll build one.

Ok I've now measured it:

http://redspade-audio.blogspot.com.a...-horns_02.html

These are nearfield measurements:



Black measured
Red simulated

I also measured each one individually, to ensure they were playing at the same level. This also ensures the dual opposed design works fully. Vibrations are cancelled very well in this design. The box is light for its size, but the walls in the room shake yet the box has barely noticeable vibrations at high output.

With room gain, the bass extends down well below 20 Hz. It's a beast! The other day I watched the Dark Knight and there was one moment where the Joker suddenly shot a big gun. The transient hit so hard it almost made me jump.

To get this kind of output I would need dual sealed Maelstrom 18" subs with 4 kw of power, or around 8 x 12" kits. The bass is clean and there is impressive authority.

In terms of sound quality it's hard to compare because I'm running it differently, with woofers covering midbass. The Rythmik subs don't really need to improve in their sound, it's just nice to have more quantity. That was the goal here and it's been achieved.

Paul,
Looks like you nailed the simulation. Makes me want to build one although for music I love my DS1505. Are you using the Rythmik servo amp to drive your beast? I’m glad to hear it met your expectations, that’s always a good thing, I would love to hear it but we are on opposite sides of the globe so I don’t think that will never happen. I have been watching your audio blog with interest, your 8” active surrounds are speakers I was looking at to build some mains not active though, may change it to surrounds to start with. I’ve made several changes to my system based on your Bass integration guide. I have a Klipsch Sub12 that I’m trying to sell setting here unable to sell it so I added it in and though it’s not close to the quality of the Rythmik it did smooth out the base. I was having a problem with phase between the two subs so I connected the Klipsch with the speaker level inputs and set the fronts to 40hz then ran the Rythmik off the sub out and was finally able to get the phase right. For some reason my AVR is cutting the Rythmik at 50hz instead of the 80hz that it’s set for but it sounds pretty good and EQ’ed well so I have left it alone for now. I appreciate what you are doing with your blog and will be following and learning.
Larry

How are Rhythmik at replying to emails?

They haven't replied to mine and I'm wondering if this is typical.

That would be unusual Steve.

There is only two people that reply to emails Brian and Enreco so be patent. I have never had them not answer me but it may take a few days they normally have a back log because they get so many.

I've had a response now Paul, so that's good.

When you had your OB Rythmik subs, did you buy them as OBs (ie the GR drivers) or get the regular kit and EQ it flat yourself?

I have a question for anybody who might be able to answer it. I have a Rythmik DS1505ci in a 4cu ft net volume sealed box which is the recommended volume for a DIY box. The F15 is around a 2.8 cu ft net volume box. My understanding is that my larger box gives me more output. My question is just how much more output does it give me. I do have a RS meter but I’m not sure how to go about measuring max output and I’m not sure I want to push it that hard to find out. I have thought about changing to a ported box for the added output but I love the way the sealed box sounds. I am about 50/50 music and movies in a 4300 cu ft very open room.

I asked the same question several months ago and the increase in SPL is not that signiicant

For changing to sealed to ported. see link below

http://www.avsforum.com/avs-vb/showt...7#post21655727

The larger enclosure will improve low freq extension, I don't believe it will increase output significantly.

Dave.

Thank guys I do seem to remember reading that. I've read so much in the last few months I forgot what I've read. I'm reading about the waterfall grafts in REW and can see how bad my room is so I'm looking into DIY bass traps. Thanks again.
Larry

I just finished a ds1510/H600peq3 build and have had problems getting answers via phone and email so hopefully you guys can help me out. I'm not complaining and have no regrets purchasing this kit. Who knows maybe I accidentally left the wrong call back number when I called.

1-according to what I've read you should use 2" of polyfill on all walls (excluding bracing) but the included polyfill was nowhere close to that so I bought some quilt poly and folded 4 layers which ended up being almost 2" thick. Should I have installed the poly that was included or did I do the right thing?

2- I know you shouldn't play certain tones for long periods during break in. Is there anything else I should know about the break in period like max volume?

3- the woofer and amp had gaskets pre installed. Do I need to use the included gaskets also? I would think not since none of them are curved to fit the woofer.

Any help you can provide will be appreciated. This thing really made my system sound alot better. I should have done this years ago.

Thanks
Joe
Edited by Joeroe - 6/17/12 at 9:18pm

you can check this thread http://www.avsforum.com/t/1214550/official-rythmik-audio-subwoofer-thread

Thanks for the help. Unfortunately the poly they provided wasn't enough to line the box. Maybe I'll just remove 2 of the 4 layers.

Did your sub and amp come with pre-installed gaskets? Mine did and they also packed extra gaskets that I did not use. I removed the amp and sub after a quick test so I can stain the box. Looks like I'll be removing some poly.

I ordered some spike feet with my kit and can't seem to find a threaded insert for them.Have any of you used these feet and if so where did you get your threaded inserts? I think the feet are 10-1.5 threads.

Mine did not come with extra gaskets.

Somewhere in the 6000 post on the other site Brian says what they are but I can't remember now. Take one to Lowes they have a thing on the wall in the nut and bolts section that you can screw it into to see what size it is. They also sell hurricane nuts and/or threaded inserts you can use to mount them with. I have used them on all of my subs but have removed them all. I couldn’t tell a difference in sound or measure one with REW and it made it very difficult to move the sub on carpet, you can’t slide it you must pick it up which you can’t do alone. If you don't like the ones at Lowes then try PartsExpress.com

I tried that and had no luck and that is why I posted this thread. I even did a google search of the size i found (10-1.5) and came up with nothing. maybe I'll just scrap the feet idea since it is so hard to move around. I plan on building a theater room next year and didn't want a big square impression in the carpet after I move it.

Thanks for all of the suggestions. I just installed REW on my laptop and ordered everything minus a SPL meter to make measurements. Should be fun.

Joeroe,
You could always use the feet until you move the sub to its permanent home, they do stop the impressions in the carpet. REW is fun after you get past the learning curve. Read all the tutorials on HTS, and a house curve does make the sub sound better. I would recommend getting a Behringer 1124 for EQ duties, it not as easy as some other units because it’s manual, but it is the cheapest and it is very versatile.
Larry

I feel like I am totally repeating myself here, but I guess I should have put this here to begin with...Sorry.

I am currently building a FV15HP and an F15HP concurrently. I am constructing the cabinets now because I have time, and I will buy the kits later (because I will have cash). I have two questions that I hope you all might be able to help me with.

1.) I will be countersinking the huge driver into my double baffle. I have already found out that this might have been a bit of a mistake, but I will make the best of it. If I expand the flush mount portion of this affair by 1/16th will it look sloppy, or is it all big enough to still look tight? That is I will go with a 15 3/8 instead of 15 5/16. Sloppy? or alright? (I have never worked with a driver nearly this big.)

2.) How does one go about flush mounting the plate amp and what are the measurements?

Sorry again. Especially to those that frequent multiple forums and are sick of seeing this.


Thanks for you help.



Jkrueger

To answer your questions, I don’t think increasing the cut out by 1/16th will be at all noticeable; you are only talking about 1/32 greater clearance around the driver. As for as flush mounting the amp none of the plans I’ve seen calls for it, it’s in the back so you won’t see it anyway so I didn’t flush mount mine. If you really want to you will have to use a router with a straight edge to guide the router using a spiral shank bit or a straight bit of some type. As far as how deep I would go about 1/16th of an inch. Are you building this from a set of plans or just winging it, you need some good bracing inside for it to sound its best. Here is a picture of the bracing I used on the inside of my FV15 clone, this is not the same as what’s in a real FV15.

I think that I have resigned myself to cutting my cabinets open when the gear arrives. Having said that, I have been bothering Enrico a lot lately. I figured that I would ask my questions here.

Is there any saving to be done if one orders two CI kits at once, or is it flat rate shipping per kit.

Thanks for your help, all.


Jon

Two kits ordered.

Two kits completed. I thought that I would post a few initial impressions here as there is probably no other place where anyone will read them.
First of all, my experience with Bryan and Enrico was excellent. They were available to the point that I was embarrassed to call again, and yet they always were great about answering my questions.
Second...the quality of the driver and amp seems really good. Everything seems to work as it should right out of the box.
Third...I have no pictures at this time, and I am a little self concious about my VERY CUSTOM installation. (The boss said, "it can go there.")

I have no previous experience with subwoofers, so everything I say following should be viewed with much suspiscion, but, I sure am glad I didn't order the 12 inch. I was understanding from what I read here that ordering the FV15HP was like taking a machine gun to a fist fight. I am pleased with the output, but it does not seem to have much more headroom than necessary. (Mind you I have not run ARC yet, and I am screwing around with HTTYD.) The air from the port moves the venetian blinds across the 14 foot room. It seems tight, good with music, sure spices up movies. I already think that I would say that if I had to do it again, that I would be happy to do the same. The FV15HP fits well with the rest of my gear, and so far I really like it.

After I run ARC I will add any further thoughts. If any of you out there are hesitant, I don't think that you will be disappointed.

Thanks Bryan.

Hello. I would like to try my rythmik sub with my 2 channel setup but I am not too sure what's the best way to hook it up. My preamp does have 2 pairs of RCA outputs but I was hoping that I could go from preamp L and R out to rythmik in and the rythmik out to main power amp. Will this let me use the crossover control on the rythmik amp to control the high pass out or is it a fixed crossover. Thank you for your time, Brian.

k7k---I don't know if you received an answer or not, but I just saw your question and figured I'd tell ya. What you want is the plate amp with HPF (High Pass Filtered) outputs. That lets you send a signal to your power amp / main speakers that has been rolled off at your chosen crossover frequency (80hz is probably as high as you want to go). The model amp that has HPF outputs is the original PEQ (NOT the PEQ 3). Hope this helps.