# Rythmik F8 Discussion Thread



## theJman (Mar 3, 2012)

Rythmik F8

By Jim Wilson (theJman)

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The Rythmik F8 fills a niche that seems to be almost universally neglected by virtually every other subwoofer manufacturer, a market segment that really doesn't get much love. Not everyone is a "basshead", the type of person who enjoys being pummeled by low frequencies from everything they listen to. There are those who want detail and refinement first and foremost, people who don't necessarily need to have the fillings dislodged from their teeth on a regular basis. The Rythmik F8 subwoofer is for anyone who savors composure and finesse, the discerning audiophile that also enjoys a good blu-ray movie on occasion. Compact in size yet big in every other way, the Rythmik F8 is the go-to choice for the discriminating individual who relishes subtlety. Pretentious and grandiloquent it's not, but eminently satisfying it certainly is.

*For the full review Click Here​*​


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## martindale (Oct 13, 2010)

Good review. I am a professional recording studio and theater designer, and have been recommending and installing Rythmik subs for several years. The price/ performance of the Rythmik line is unsurpassed, and my clients who now use these subs (in professional settings as well as HT) have all been blown away, especially in comparison to other manufacturer's subwoofer products. Brian Ding is a dream to work with, and the technology in the subs enables optimization in any critical listening environment.


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## vidiot33 (Dec 12, 2013)

Excellent review! I recently bought a pair of FMB 8's to provide some mid bass kick to my Sierra 2's. I think good mid bass response is a very underestimated element of good sound.

Sent from my iPhone using HTShack


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## theJman (Mar 3, 2012)

vidiot33 said:


> Excellent review! I recently bought a pair of FMB 8's to provide some mid bass kick to my Sierra 2's. I think good mid bass response is a very underestimated element of good sound.


My guess is you're going to have quite a smile on your face with that setup. Be sure to leave your impressions when the opportunity presents itself.


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## 3dbinCanada (Sep 13, 2012)

Thanks for the nice review Jim.


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## theJman (Mar 3, 2012)

:T


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## vidiot33 (Dec 12, 2013)

theJman said:


> My guess is you're going to have quite a smile on your face with that setup. Be sure to leave your impressions when the opportunity presents itself.


 You are correct sir! The bass is uncompromising, clear, nuanced and powerful! Brian Ding, the owner of Rythmik (and a phD in electrical engineering) made the point that the most impactful bass is not in the lowest registers, but in the 60-70 HZ range. He offers the FMB 8 to captures these, and man do they deliver! Besides the great bass, all of the low notes appear that they are coming from the front, even though I have 4 subwoofers (2FMB &'s and 2 sealed Rythmik 15's), a characteristic I attribute to the efforts I made to phase align them. This should be standard operating procedure for anyone who likes to hear all the bass powerfully. No matter the size of your fronts, they aren't going to perform like these babies, particularly when most fronts (including mine) are not in the optimal position for bass reproduction. Highly recommended!!!

Sent from my iPhone using HTShack


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## bkeeler10 (Mar 26, 2008)

Great review Jman. Sounds like these things live up to Rythmik's MO and reputation. Since you also have an E15HP, I am wondering if you could detect any evidence that the cliche "big woofers are 'slower' than smaller woofers" is true? I have not really bought into that myself, but I'm curious what you think.


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## theJman (Mar 3, 2012)

bkeeler10 said:


> Great review Jman. Sounds like these things live up to Rythmik's MO and reputation. Since you also have an E15HP, I am wondering if you could detect any evidence that the cliche "big woofers are 'slower' than smaller woofers" is true? I have not really bought into that myself, but I'm curious what you think.


There is some physics behind inertia and mass, so I'm not certain it can all be discounted. After all, no matter how large the engine and brakes are on a tractor trailer it will never accelerate and stop as fast as a Corvette will. That being said...

When properly designed and engineered a subwoofer with a larger driver can be made to respond in a manner quite similar to that of a unit with a smaller driver. You might be able to measure the difference between the two, but done properly it can be made virtually inaudible. Case in point, my next review will be on the JTR Captivator S1. Without giving too much away, the motor strength, wattage of the amp and alignment make for something that looks beastly yet sounds anything but. The FV15HP would be another case study; there's no way that thing should sound as good as it does, but somehow Rythmik pulls it off. To an extent you can have your cake and eat it too, but it takes a lot of time and effort for that to happen.


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## ronno1973 (Feb 26, 2015)

Looks like they could have fit a couple of 12"s in there ... Someone had to say it.


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## bkeeler10 (Mar 26, 2008)

ronno1973 said:


> Looks like they could have fit a couple of 12"s in there ... Someone had to say it.


Perhaps. They did just release a sub with a pair of 12" woofers though. It is called the L22, and the price is surprisingly reasonable. The box is significantly bigger though.


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## theJman (Mar 3, 2012)

ronno1973 said:


> Looks like they could have fit a couple of 12"s in there ... Someone had to say it.


The enclosure is actually quite small, with no room for even 10" drivers. When you look inside it becomes even more apparent because of all the bracing.


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## mirekti (Mar 25, 2016)

My first post here, but I have been browsing around for some time. 

I've been comparing frequency responses between F12G and F8. The plots of F12G seems to be totally smooth compared to F8.
My goal is to use two F8s to augment Harbeth P3ESR and looking for some small sealed solution that would fit the room and not took too much attention. F8 is a perfect candidate due to its narrow profile. 
What do you say how these two compare to each other?

Thanks!!!


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## theJman (Mar 3, 2012)

mirekti said:


> My first post here, but I have been browsing around for some time.
> 
> I've been comparing frequency responses between F12G and F8. The plots of F12G seems to be totally smooth compared to F8.
> My goal is to use two F8s to augment Harbeth P3ESR and looking for some small sealed solution that would fit the room and not took too much attention. F8 is a perfect candidate due to its narrow profile.
> What do you say how these two compare to each other?


Welcome to HTS. :wave:

Is your setup for 2 channel music by chance? I'm guessing so by the speakers you have. Also, when you say "match the room" what does that mean? Is that from a visual perspective, size related, performance characteristics, something else perhaps?

Both of the subs you're looking at are highly regarded, so it's not as though there's a bad choice, but there's probably one better suited to the task at hand. We'll need a couple more pieces of info and we should be able to help dial it in.


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## mirekti (Mar 25, 2016)

theJman said:


> Welcome to HTS. :wave:
> 
> Is your setup for 2 channel music by chance? I'm guessing so by the speakers you have. Also, when you say "match the room" what does that mean? Is that from a visual perspective, size related, performance characteristics, something else perhaps?


Than you very much!!

Yes, its purpose is music, but I do watch movies or TV. Fit the room meant to aesthetically fit the living room. 
One other think to add is, I don't listen to the music (or watch TV) very loud and my goal is to simply extend the octave, perhaps a bit more of P3ESR.

Cheers!!


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## mirekti (Mar 25, 2016)

Just a quick update. I've been using two F8s with Harbeth P3s for five days and they are really, really good. I also purchased minidsp 2x4 to heal a bit the room modes. I am truly impressed with F8s. 

At the moment I have the crossover set to some 70Hz and run P3s full range, but have an option to modify my integrated amp to 4 channels. two with HPF 24db/octave and two full range. 
The only caveat being HPF frequency needs to be defined in advance i.e. it won't be adjustable. 
Having that said, this shouldn't be a problem as F8s have adjustable crossover and it can find its way to meet P3s. I am just not sure which point to choose. 
80Hz is somehow HT recommendation, but F8s will be under P3s so localization of sound wont be a problem.
I've read somewhere monitor speakers should be crossed over one octave higher from where they roll off. In this case that would be 150Hz, but I am not sure how will F8 behave if crossed so high. It is rather high for a subwoofer. 
Than then next option is 100Hz or 120Hz i.e. somewhere in between first two.

What would be your thoughts or suggestions? What is the highest I should go with F8s? 
As mentioned before, HPF will be 24dB/octave so the same will be set on F8s back panel.


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## theJman (Mar 3, 2012)

My apologies for the late response - emails from HTS were not always coming through for some reason, and the notice that this thread was getting new posts was among the missing. :foottap:



mirekti said:


> Just a quick update. I've been using two F8s with Harbeth P3s for five days and they are really, really good. I also purchased minidsp 2x4 to heal a bit the room modes. I am truly impressed with F8s.
> 
> At the moment I have the crossover set to some 70Hz and run P3s full range, but have an option to modify my integrated amp to 4 channels. two with HPF 24db/octave and two full range.
> The only caveat being HPF frequency needs to be defined in advance i.e. it won't be adjustable.
> ...


Whether they're monitor speakers, bookshelf or tower the concept for crossover is pretty much the same; before your speakers run out of gas, that's where the crossover should be set. Ideally this is determined with measurements, but you can also very effectively use the manufacturers specifications. Assuming they're accurate, of course.

According to Harbeth's website your speaker has an F3 of 75Hz, so for moderate volume I would suggest no less than 80Hz. Why qualify that statement with the word "moderate"? Because once you start pushing a speaker things change, so the more volume you like the further from that F3 you'll need to go in order to mitigate distortion (and seeing as how you have Harbeth speakers and a Rythmik subwoofer I'm guessing that's very important to you). Personally I would think you could easily do 100Hz with the F8 if you chose to do so, especially if you're using a 24dB roll-off.


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## mirekti (Mar 25, 2016)

Just a quick update. Rythmik F8s are really remarkable subs. Perfect for music, lovely with movies. 
I added miniDSP between line level and F8s to get rid of some room issues in bass region. P3s are fed by amp which has HPF @100Hz 24dB/octave at the line level.

All in all, I would highly recommend F8s to anyone who appreciates bass quality, especially the music lovers.


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## theJman (Mar 3, 2012)

mirekti said:


> Just a quick update. Rythmik F8s are really remarkable subs. Perfect for music, lovely with movies.
> 
> All in all, I would highly recommend F8s to anyone who appreciates bass quality, especially the music lovers.


Excellent assessment, as it mirrors my own quite well... 

_"The Rythmik F8 subwoofer is for anyone who savors composure and finesse, the discerning audiophile that also enjoys a good blu-ray movie on occasion"_


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## Schrodinger23 (Sep 2, 2017)

vidiot33 said:


> Excellent review! I recently bought a pair of FMB 8's to provide some mid bass kick to my Sierra 2's. I think good mid bass response is a very underestimated element of good sound.
> 
> Sent from my iPhone using HTShack


Are you using subwoofers in addition to the FMB 8's?


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