JiggaD369 said:
If you have a lineout using RCA outputs and if you can use that to power your subwoofer, it's way better to use that.
If you can't use that, I recommend running front speaker wires from the receiver to the high-level imputs on the subwoofer and then from the high-level outputs fron the subwoofer to front speakers. It's not the best method, because you now have a 80 Hz crossover directly in the subwoofer which prevent using low end extension of your mains speakers if they can go below 80 Hz and this forces you to crossover the subwoofer around 80 Hz too.
Some interesting things happen when you apply the filters to the low and mid Q designs. The mid Q actually produces more output in a lot of the band that you will be using. The group delay is a little lower. However, once the 3dB (one penalty of the mid Q design) loss is accounted for, and the fact that the low Q design is bullet proof below 20Hz, I think the low Q route is a better one. The difference in group delay is probably not very noticable, and the mid Q version would require a bit of tweaking, which is probably not worth the effort if you want a solid plug and play system. So if you are looking for a definitive consensus, there you have it. Simon5 and I both agree that the low Q (no resistor, short the gold terminals) is the best option.
i have a SUB pre-out which i think is the same.
http://www.marantz.com/image/products/u_sr8400_bck.gif
http://www.marantz.com/image/products/u_sr8400_bck.gif
Oops! I finally get what you mean, I think. Digital outputs (which use coax) tend to sound better, particularly over long runs due to reduced line loss. However, I don't think the Rythmik (or most plate amps) accept digital inputs, and RCA and digital signals are not compatible. So that kinda leaves you with RCA or speaker wire, in which case the RCA is a much better option.
I probably started this confusion when you initially asked how to wire your sub (coax or silver plated copper, I think). I have heard of some people wiring the voice coils of the sub with coax wire (like cable television uses). I think it is a car thing. Anyway, sorry if I confused you.
That looks like a nice receiver. I had a Marantz about 10 years ago and really liked it. It was the first piece of "real" audio gear I ever owned. Yours has a lot of connectors and connector types, which is always very nice.
I probably started this confusion when you initially asked how to wire your sub (coax or silver plated copper, I think). I have heard of some people wiring the voice coils of the sub with coax wire (like cable television uses). I think it is a car thing. Anyway, sorry if I confused you.
That looks like a nice receiver. I had a Marantz about 10 years ago and really liked it. It was the first piece of "real" audio gear I ever owned. Yours has a lot of connectors and connector types, which is always very nice.
hey which amp am i getting? the 250 Special Edition 12 db or 24db? and it says something about rumble filter. whats that about?
"The default rumble filter is set at 12hz with Q=0.7. For vented box and infinite baffle configuration, one needs to modify this rumble filter to prevent over-excursion (or bottoming) of the woofer. This can be easily modified by soldering 2 resistors on the back of the preamplifier without (the hassle of) taking out the preamplifier board. Click here for more details. We can do the soldering for you for a nominal $5 charge."
"The default rumble filter is set at 12hz with Q=0.7. For vented box and infinite baffle configuration, one needs to modify this rumble filter to prevent over-excursion (or bottoming) of the woofer. This can be easily modified by soldering 2 resistors on the back of the preamplifier without (the hassle of) taking out the preamplifier board. Click here for more details. We can do the soldering for you for a nominal $5 charge."
The rumble filter is a highpass filter at the lowest end of the sub's frequency range. The purpose of the filter is to block infrasonic material that can overextend the driver and generally produce undesirable effects (rumbling; thus, rumble filter). Vented and ported designs can have additional nasties below tuning the frequency. Its a good thing, and with the Atlas 12 design you are looking at, I think the default setting of 12Hz is about right.
ok thats what i wanted to make sure that i didnt have to perform that mod they listed in my previous post. as long as it works with my sub. 
HEy, i wanna give thanks to Raoul, Simon and whoever else that helped me out on this project. I really appreciate you guys taking your time to help a noobie out and actually educating him some things. you guys are awesome. hopefully this DIY goes smooth. thanx alot.
HEy, i wanna give thanks to Raoul, Simon and whoever else that helped me out on this project. I really appreciate you guys taking your time to help a noobie out and actually educating him some things. you guys are awesome. hopefully this DIY goes smooth. thanx alot.
If you are going for the Rythmik 250 SE, I think that you will want the 24dB lowpass filter. This applies if your front speakers are vented. I think this will make the best match, as the vents in your mains are equal to a 24dB highpass filter, if memory serves. You will probably want to set your sub highpass low (40-ish) to blend in with your mains, which I think have a F3 of 38Hz. Sometimes manufacturer's spec.s are a bit optimistic, but the filter is easy to play around with, so adjust it until it sounds right. Also, the folks at Rythmik are suppose to be quite friendly and helpful, and can probably offer you more advice.
Have fun and let us know how it turns out...
Have fun and let us know how it turns out...
Also, when using the filter on the Rythmik amp, remember to turn off any sub filters on the Marantz. The Rythmik Special Edition amps look very nice, with a lot of nice mods to the basic models. If you want to stay closer to your $300.00 limit, though, you could also use the 250 basic model. This is especially true if your Marantz has a 24dB lowpass filter somewhere around 40-50Hz. I'm not trying to talk you out of the SE, as the mods look quite nice and seem well worth the money (read: better amp), just trying to provide options that keep you closer to your original budget. If you can expand your budget, go for it.
To simon5: Do you still have this project in WinISD? Just wanted to make sure the 12Hz rumble filter is the best lowpass point.
To simon5: Do you still have this project in WinISD? Just wanted to make sure the 12Hz rumble filter is the best lowpass point.
Rythmik Audio amplifiers can run with a stereo RCA cable or a mono RCA cable. If you use mono, you use one imput, left or right RCA imput, which is the way you're gonna use this amplifier with your receiver, using the subwoofer RCA pre-out.
I would leave the rumble filter at the default value. It would protect the woofer a bit better if it was higher, but it would compromise the response at low frequencies. Not alot material got sounds in the 7.4 Hz to 15.4 Hz frequency band where the woofer could be in overexcursion and that would only happen at full power. Outside of this band, the woofer is fully protected.
I built a Shiva with this enclosure and the Rythmik Audio 250 basic and I had no problems with overexcursion, except with sinusoidal test tones at stupid loudness at around 10-15 Hz. The Atlas 12 is even better built because the woofer can't hit the backplate so it's very hard to damage it. You will hear it anyway if you're asking too much.
If you're going with the SE version, I would go with the 24 dB crossover.
I would leave the rumble filter at the default value. It would protect the woofer a bit better if it was higher, but it would compromise the response at low frequencies. Not alot material got sounds in the 7.4 Hz to 15.4 Hz frequency band where the woofer could be in overexcursion and that would only happen at full power. Outside of this band, the woofer is fully protected.
I built a Shiva with this enclosure and the Rythmik Audio 250 basic and I had no problems with overexcursion, except with sinusoidal test tones at stupid loudness at around 10-15 Hz. The Atlas 12 is even better built because the woofer can't hit the backplate so it's very hard to damage it. You will hear it anyway if you're asking too much.
If you're going with the SE version, I would go with the 24 dB crossover.
JiggaD369 said:
Haven't read through the whole thread, but if nobody else has suggested it, why not try a sonotube sub. You get a small foot print and plenty of cubic foot volume. 5 cubic feet can be had from a tube as small as 16" diameter once you calculate the length of the tube. SVS does very well this as has Hsu. Construction will be much easier for a novice,(like me). You can then go for the biggest volume that will give you the deepest bass. Decorate it, paint it however you want and enjoy.
I'll be doing the EBS suggestion from Adire with my own Shiva in the next few weeks, just want to check with the wifeage to see what size tube will offend her the least.
Hi Arthur-itis,
The sonosub idea had been suggested, but JiggaD369 has opted for a more traditional box. I am not sure if you are planning on venting your Shiva, but you will probably need at least an 18" tube to allow for a vent if you do (unless you vent through the top). Sixteen inches doesn't allow for much of a baffle, if any, between the 12" Shiva and a 4" pipe.
Another idea I had for venting a sonosub would incoporate two different size sonotubes -- one inside the other. The driver would mount on the smaller tube. The bottom of the smaller tube would then be mounted flush with the bottom of the larger, exterior tube, and the space between the two tubes would essentially form a large vent (or two, depending on mounting technique). I haven't pursued the idea, and have yet to try modeling the idea to see if it is plausible. It could provide a very large vent, but the required length may be excessive, depending on the driver. Maybe (probably) this isn't a new concept, but I haven't seen it used before.
The sonosub idea had been suggested, but JiggaD369 has opted for a more traditional box. I am not sure if you are planning on venting your Shiva, but you will probably need at least an 18" tube to allow for a vent if you do (unless you vent through the top). Sixteen inches doesn't allow for much of a baffle, if any, between the 12" Shiva and a 4" pipe.
Another idea I had for venting a sonosub would incoporate two different size sonotubes -- one inside the other. The driver would mount on the smaller tube. The bottom of the smaller tube would then be mounted flush with the bottom of the larger, exterior tube, and the space between the two tubes would essentially form a large vent (or two, depending on mounting technique). I haven't pursued the idea, and have yet to try modeling the idea to see if it is plausible. It could provide a very large vent, but the required length may be excessive, depending on the driver. Maybe (probably) this isn't a new concept, but I haven't seen it used before.
Hi,
I noticed your post about the tube within a tube. You stated:
Another idea I had for venting a sonosub would incoporate two different size sonotubes -- one inside the other. The driver would mount on the smaller tube. The bottom of the smaller tube would then be mounted flush with the bottom of the larger, exterior tube, and the space between the two tubes would essentially form a large vent (or two, depending on mounting technique). I haven't pursued the idea, and have yet to try modeling the idea to see if it is plausible. It could provide a very large vent, but the required length may be excessive, depending on the driver. Maybe (probably) this isn't a new concept, but I haven't seen it used before.
~~~~~~~~~~~~~~~~
I hate to be a bearer of bad news, but several years ago I was over at Adire Audio when it was down on Elliot Ave in Seattle and Dan Wiggins had one of his 18 inch woofers downfiring out of an enclosure exactly like you have described. It reminded me of a circular "Oinkin' " cabinet. If I remember correctly Dan used 1 x 2's around the perimeter to not only space the two tubes apart but also to get the correct vent area. The 1 x 2's extended down and also supported the Sub, functioning as legs.
If you contact Dan, he might be able to tell you the particulars on his contraption:^) I think this once again proves the old axiom that great minds think alike, congrats.
Best Regards,
TerryO
BTW: They sounded pretty good!
I noticed your post about the tube within a tube. You stated:
Another idea I had for venting a sonosub would incoporate two different size sonotubes -- one inside the other. The driver would mount on the smaller tube. The bottom of the smaller tube would then be mounted flush with the bottom of the larger, exterior tube, and the space between the two tubes would essentially form a large vent (or two, depending on mounting technique). I haven't pursued the idea, and have yet to try modeling the idea to see if it is plausible. It could provide a very large vent, but the required length may be excessive, depending on the driver. Maybe (probably) this isn't a new concept, but I haven't seen it used before.
~~~~~~~~~~~~~~~~
I hate to be a bearer of bad news, but several years ago I was over at Adire Audio when it was down on Elliot Ave in Seattle and Dan Wiggins had one of his 18 inch woofers downfiring out of an enclosure exactly like you have described. It reminded me of a circular "Oinkin' " cabinet. If I remember correctly Dan used 1 x 2's around the perimeter to not only space the two tubes apart but also to get the correct vent area. The 1 x 2's extended down and also supported the Sub, functioning as legs.
If you contact Dan, he might be able to tell you the particulars on his contraption:^) I think this once again proves the old axiom that great minds think alike, congrats.
Best Regards,
TerryO
BTW: They sounded pretty good!
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