[drake]

I took the plunge and ordered the woofer and passive radiator from GR-Research. Now for the amp, is the apex senior http://www.apexjr.com/Apexsenior.htm a good amp or is there a better option. The wife and I like the idea of the remote control. Any advice would be greatly appreciated. : )

Matt 

[gitarretyp]

If you don't mind losing the remote (sounds important to you), this rythmik audio amp is a modded version of the apex senior with some nice features added for the same price.

[Daygloworange]

Hey, that looks interesting. Anybody compare that to the stock Apex amp?

Cheers

[warnerwh]

I've been using a Rythmik 350SE for almost two years and it's a good amp for the money. Good chance I'll buy another one for a HT sub.  The guy's service is very good.

[gitarretyp]

I should have added that i own one of the rythmik amps and am very happy with it. Brian is a good guy to deal with, also.

[andyr]

Aha ... I fired up my Rythmik servo sub only last week ... and I second all the above comments!     Brian is a great vendor - very helpful (always answers my Qs!!    ), prompt ... and the product is fantastic!!     What more can you ask for?

As you've already bought another driver, though, the Rythmik servo amp may be irrelevant to you?

BTW, I suggest a remote is of limited use.  Certainly when you're setting it up, it would be great to be able to sit in the listening chair and press buttons to change sub level (volume), cutoff frequency and phase but after you've set it up ... you don't change these settings!  Without a remote, you need a helper ... given female hearing is more acute than male, I suggest it's better to have your "SO" sitting in the listening chair while you manipulate the controls!   

Regards,

Andy

[Christof]

Can you guys give more opinions of the Rythmik Servo?  I don't feel the Servo(kit) is what Drake is looking for I'll start  another thread as not to sidetrack this one.

[drake]

Thanks guys for the help!! The remote is important but only to a point. If the Rythmik amp is that
much better then I can forgo the remote. It looks like the only difference between the two amps
are the mods made by Rythmik. Other than that it looks to be the same amp. It this correct?

I was torn between the GR-Research driver and Rythmik servo amp and woofer combo but when I modeled both subs in WINISD pro they modeled almost exactly the same and the TC Sounds driver is twice the cost of the GR-Research driver. 

Matt

[gitarretyp]

Thanks guys for the help!! The remote is important but only to a point. If the Rythmik amp is that
much better then I can forgo the remote. It looks like the only difference between the two amps
are the mods made by Rythmik. Other than that it looks to be the same amp. It this correct?

I was torn between the GR-Research driver and Rythmik servo amp and woofer combo but when I modeled both subs in WINISD pro they modeled almost exactly the same and the TC Sounds driver is twice the cost of the GR-Research driver. 

Matt

Did you take a look at the group delay? Also, did you model the rythmik driver with the same eq as the servo amp applies --the rythmik will reach lower? If you look at max spl in winisd, you'll also see that the rythmik driver is capable of more ouput away from the gr sub's tuning frequency. The distortion specs of the two will also be rather different, which winisd will not tell you.

[drake]

No I did not look at the group delay. I will take a look at that. Not sure how much effect group delay would have on a sub though?
I did however research F3 point of each sub. With the right modifications to the apex amp the GR sub will be at -1db at 20hz. Not taking into account room gain. Now that is really low, how much lower does one really need to go? If pushed by the same amplifier how would the Rythmik produce more output?? Both the sd’s of the drivers are similar and with 250watts neither one is going to reach full XMAX. Am I missing something here??

Matt

[gitarretyp]

No I did not look at the group delay. I will take a look at that. Not sure how much effect group delay would have on a sub though?
I did however research F3 point of each sub. With the right modifications to the apex amp the GR sub will be at -1db at 20hz. Not taking into account room gain. Now that is really low, how much lower does one really need to go? If pushed by the same amplifier how would the Rythmik produce more output?? Both the sd’s of the drivers are similar and with 250watts neither one is going to reach full XMAX. Am I missing something here??

Matt

High group delay can lead to blurring of transients, especially if you're using a high'ish crossover point. If you're using the apex amp, you'll have 350W. That's enough to drive both drivers past xmax. Part of the reason the rythmik will have more deep bass is that it's in a sealed enclosure rather than the pr design of the gr. Sealed has a 12db/octave roll-off; whereas, the pr will roll-off at 24db/octave. If you apply the default setting for the linkwitz transform to the rythmik in winisd, you'll get an idea of the response with the servo amp.

[drake]

Ok, I can buy the fact that group delay would effect the woofer if I crossed it over high but being that it is a sub woofer and will be crossed over at 60hz - 80hz I just don’t understand how group delay would effect the sub.

I follow you on the roll off of a sealed vs. ported but how in the world would this have any effect at all if the darn passive radiator design is 1 db down at 20hz! The apex amp puts out 250watts at 8 ohms, and the GR sub is an 8 ohm sub.

Again I ask why does anyone need a sub that goes lower than 20hz.

So, far what I have gathered the servo sub is MARKETING HYPE and nothing more but I have been wrong before.

Now one could argue that the servo sub has the speed of a sealed box and the extension of a ported enclosure but will it have the output of a passive radiator design??
Being that the passive radiator design uses both the front wave and the back wave of the woofer. Hummmmmmmm

[drake]

Thanks for all this discussion about the Rythmik. It has made me really think!!!  In a good way but now I really don’t know which amp to get. lol
I could get the Rythmik amp with the LT built in
I could get apex amp with the remote
I could get the BEHRINGER EP2500 and the DEQ2496
I could get the Carvin DCM2000 and the DEQ2496
And then there is the Buttkicker and the DEQ2496

Did I miss any?

Matt

[audioferret]

The adjustable dampening and extension on the Rythmik amp is a very compelling reason to choose it, in my opinion.  Even with very precise modeling, your actual response will vary given your final sub build characteristics and room response. These two switches will grant you the ability to select a response that suits your taste.

Have you seen other amps that have this feature?