Official Rythmik Audio DIY Subwoofer Kit thread

this should be good. lets see what he says

i used their DS1200V plans and built my own

and i must say i am very impressed at how well it performed.

i give my 2 thumbs up at the DIY version of their subs, just as feedback for those on the fence about it.

I built my own enclosure for the DS1500. It performs well. I want another one. They will make great sounding book ends!

I have a 12" Direct Servo kit in a custom built enclosure. Best sounding sub I've had in my system!

Hello.

My humble, yet unfinished, DS1200 project pictures can be viewed here: "http://www.dvdplaza.fi/galleria/showgallery.php/cat/1223". Unfortunately I'm not yet allowed to post the actual www-address.
Hopefully I get some bass out of the sub before the end of May. My expectations are high because of all the good reviews these kits have gotten.

Here my Rythmik retrofit project, gave new life to my old HSU sono sub:

http://www.avsforum.com/avs-vb/showt...292&highlight=

Just recently I added a table over it, still working great.

http://www.avsforum.com/avs-vb/showt...7#post18249717

I have two enclosures stacked on top of each other, 2 x 15" kits per enclosure, firing through my equipment room wall into the back of my theater. This combo is paired with a DTS-10 in the front. The Rythmiks remain the best sounding subs I have had in my theater. If I could have the servo goodness in the tapped horn enclosure, it would be the best of all worlds!

Here some pics of my 12" servo sub. Needs a bit of a dusting!

I wanted to post a thank you to Brian and Rythmik for supporting me with a 12" woofer from a kit that I purchased (one of two) that failed when the voicecoil developed a bubble in the aluminium bobbin that the voicecoil wires are wound around. I had not been abusing the driver, it was doing duty in my living room adding a bit more weight to the bass for my stereo speakers and was hardly used, and never turned loud (the one in my home theater gets a solid pounding and has been running fine). It developed a rasping sound which over time got worse.

I initially emailed Brian to see if he could help me diagnose the problem, and Brian asked me to disassemble the woofer and take photos of the voicecoil to look at the cause of failure and to check to see if was abused (overheating - usually shows with scorch marks on the voicecoil, but mine was clean). The aluminium bobbin had a bubble in one spot rubbing against the magnet. I did try to smooth it out and re-attach the cone but this only worked for a month and the rasping came back, possibly because I could not re-glue the spider perfectly and the cone was probably slightly misaligned. At the time Brian did recommend a replacement driver under warranty (it was 2 1/2 years old) but I thought I'd try the fix first to save the hassle of replacement.

When the fix failed, Brian arranged for a new driver and updated servo board (to suit the new driver which is slightly different to the original) to be sent to me from the factory. Brian was very helpful with diagnosing the problem and with organising the replacement, which other vendors may not have bothered with especially as it is easy to abuse subwoofers and void any warranty. The new driver slipped into its DIY cabinet and the daughterboard swap was easy, and the subwoofer was up and running in 20 minutes.

So a big thank you to Brian for his support and to others considering buying a Rythmik, the quality of aftersales is always the ultimate test of a quality vendor so I have no hesitation is recommending Brian and his Rythmik products!

Regards,
Dean
(PS. If you do abuse your subwoofer and it does blow because of an overheated voicecoil, you should not expect the vendor to support you under warranty).

Is the white powder dust on the rubber surround just a cosmetic issue or does it affect the material?

Thanks for the tip, Brian. The powder may actually be dust. I had the driver and amp disassembled from the enclosure while doing an amp swap from the previous, non-PEQ model to the newer one(Remember enabling me to do the upgrade as well as sending me some Dacron material to line the enclosure?).

I had been running the original amp/driver in this same box for almost 1 1/2 years with no problem. When I moved into a house with no place to set up my equipment I decided to upgrade the amp, finish the box with satin black Krylon and construct a metal & wood grill.

I will try your tire dressing trick when I can actually have the sub hooked up again!

Thanks for all your support Brian!

Ed

Hello.

My DS1200 kit is now almost finished. The sub is in use and I'm doing some adjustments and measurements with Room EQ Wizard. I'm going use flamy birch veneer to finalise the box later on.

Here's some pics of the sub:

Attachment 173055
Attachment 173056

And here are the measurements I made with REW:

Attachment 173057

The RED line is the sub, GREEN line is the front speakers and
BLUE line is for both.

The measurement for the sub is quite ok, but the main speakers seem to go up and down like a rollercoaster. Any ideas how to improve the results? Maybe I should try the other possible position for the sub which is a corner.

Cross-over frequency is set to 80 Hz in my Marantz SR4001 amp, and it's the lowest possible. Maybe I should increase the cross over frequency to 100 Hz?

The settings in the amp are as follows:
Rumble filter: ON
Bass Extension: 28 Hz, hi damping
Cross-over: 12 dB/ext, knob at ~80 Hz

Mårde:
Are these mesurments stoothed by 1/3 octave? I would try a different posision for the sub, the other corner perhaps? What about phase, you've tried different settings? With the driver facing down, I would try to stay at 80 Hz crossover, but try it out yourself But with the crossover at 80 Hz on your receiver, you can turn the crossover knob om the sub well above 80 Hz, you might get smoother transition between sub and fronts, if you've got the phase right

Nice build btw.

And about downward vs. frontmount driver. Is there anything to gain by having the driver facing down? Except the finish of the cabinet might be easier. Better roomintegration? I'm asking because I already own a F15 and plan to build a clone, but if a downfired driver gives some advantage, I just might sell the F15 an build 2 downfireing.

tols1:
The smoothing applied is 1/6 octave. I think you're right about the cross-over setting in the sub: now I have the amp's and sub's cross overs in use at the same frequency.

I adjusted the phase of the subwoofer by running cross-over frequency (80 Hz) test signal from REW, and then I turned the phase knob from the amp until I got the highest SPL.

I don't know about the pros/cons of the downfiring sub. I used it because now it's safe from my 1 year old son...

Well, what kind of crossover setting applies best is of course different for different setups.

By the way, are you sure you have the correct calibration file for REW? The sub should absolutly give you more below 20 Hz. My graphs had the same steep drop just below 20 Hz, but when I installed the correct calibration file, things looked better.

The downwardfaceing design is of course more secure with kids i the house

I have the analog RadioShack spl-meter and I downloaded the calibration file from radioshack's forums. So I think this issue should be covered. Ofcourse there might be individual deviations between these cheap spl meters.

I have the bass extension switch in 28Hz/hi damping position, and also the rumble filter is on. Without these settings my room amplifies the 20-40 Hz region too much.

Now I placed the sub into the corner and changed the cross-over setting to 100 Hz. See the results attached. The 20-40 Hz level is 5 dB higher than target level. Smoothing octaves is set to 1/12.

Ok, so it's your rumblefilter and 28 Hz damping that causes the quick cutoff at 20 Hz then.

Well, calibration isn't easy. When I calibrate, I turn the knobs just a little bit between each measurement, until the result is as good as possible, so I suppose you'll just have to keep adjusting. It's also a good idea to keep the measurements of the fronts separate on the screen while measuring, it's easier to see where you have phase issuses. Maybe the absolute correct phase at 80 Hz isn't the optimum target in yout case.

OK, I'll try that. Thanks for your input and for a great product!

So are you saying the Rythmiks are better sounding than the DTS-10?

Yes, they are. They are not as loud, but they more accurately produce bass frequencies when compared to a DTS with no EQ. If you EQ the DTS, it is closer in sound quality to a Rythmik, but not quite as good.

I'm in the process of building a couple enclosures and I would like to flush mount the amp. What is the thickness of the aluminum used for the amp? Visually, it looks like 6-8mm thick.

Thanks, Brian. Hopefully, a router straight bit will ease the process a little bit. Is this a complete drawing or a finished enclosure?

Brian,

I am interested in the ds1500 diy kit but had a couple of questions.

Do you have a near field response graph for this sub in a sealed enclosure?
I am interested to see how low it can go before it starts to fall off.

I have read a couple paces that the plans you have on your website for the 3.0 ft^3 box is actually a little larger. If that is the case would you recommend adding .5ft^3 to that design if someone were to buy the kit with the 300W amp or would it be better to design a box with 3.5ft^3?

Can you comment on the differences between the 300W and 370W kits for the 15" woofer. From what I've read the differences would be unnoticeable except for one has a larger enclosure.

I'm on the edge of buying two Rythmik 370PEQ amps secondhand. They've never been used and the price is good. Only thing is, the seller is unsure if they are with or without servo. Also he bought them for an open baffle project he didn't start.

So my questions are:
1) If they are without servo, are they still good amps? Or will any other plate amp like OAudio Bash or Hypex DS4.0 be just as good? The benefit with the Rythmiks are of course the servo, I already own a F15 so I'm considering building a clone or two.

2) If they are servoamps but buildt for OB, are they unusable for closed og vented designs? Can they be easily modified to work in closed/vented cab?

Thanks a lot Brian. I'll ask him to mail me a photo.