Official Rythmik Audio Subwoofer thread - Page 108

You know you're looking at results with the sub pushed to max distortion allowed by the particular spec, right? You understand that the sub wad driven until one or more distortion products were at the limit that defines "clean" under the CEDIA standard. You know we aren't seeing the sub's native response without servo, right? So we do not know how much "clean" headroom the 2d order reduction provides (most subs I've seen measured have 2d order as the overwhelming majority f the distortion), and we do not know how much higher order distortion the servo is removing.

Assuming you can hear 3d order distortion at -20 dB in the relevant ranges, you'd want to use the sub at lower volumes to keep the distortion down. But it seemed to me your initial point was that the servo did nothing, then when presented with evidence that it does indeed do something, you shifted without mentioning it to an implicit attack on the apparent lower degree of control at higher orders.

BTW, I have only done a littel IP law, but Brian's right on. You protect some things with a patent, and others with trade secrets. Depends on the nature of the intellectual property in question (is it patentable, does revealing the tech in a patent application make it too easy for a competitor to design a workaround to compete with you without infringing the patent?) IIRC, you can't patent computer code, but you can copyright it. Can't patent the Coke formula. That has to be a trade secret . . .

If none of that involved distortion, what is spider distortion?

Yes I can see that the subs are pushed to their limits which is probably not a fair test but even so there is not a lot of reduction in THD compared to other non servo subs and 3rd harmonic is going to be more noticeable than 2nd but like you said there is no reference to base it on so we don't know how the sub performs without this system. It maybe that the raw driver and enclosure has low 2nd harmonic distortion in the first place and the application of this servo system improves it a little bit more.

I encourage people to ignore trolls. Either conceptually or via forum tools. Nothing further productive will come from further conversation.

However if should you wish to join the field of conflict then either a control theory thread could be started or you could join one of the unpleasant arguments currently extant in on the speaker DIY forum sites.

DS1501 is our baseline driver. DS1505 is one piece dish with larger magnets. It has slightly longer stroke than DS1501. It also extends 10hz higher than DS1501. DS1505 has the same excursion as DS1501

Other than that, the difference between DS1501 and DS1505 is mostly aesthetic.

FV15 use DS1501 as F15 and F25.

Thanks. So both FV15 and FV15HP get the DS1501? What subs get the DS1510 and how does that one compare to the other two? And what are the ohms that the different subwoofers are set at?

DS1501 and DS1505 drivers works for A370 amp (370 watts) and that is the max we recommend. Xmax for both drivers is 15mm.
DS1510 driver works for H600 and H550 amps and the Xmax is around 21mm.

In terms of volume (cu ft) DS1501 and DS1505 are 0.25 cu ft. DS1510 is 0.35 cu ft.

In terms of parameters, in Brian's words:

"Their parameters are very similar. And that is intentional. For instance, DS1510 is only 20g heavier in terms. Most importantly, those parameters are really just for reference. Our servo will take care the frequency response. Customers don’t even need to bother with T/S parameters. That is the whole idea of our CI. It is completely fool-proof."

When AP came out with their servo sub I liked the sound but it was too small and pricey for me. Velodyne came out with their accelerometer based design a year or three later. The first sub I built used a second voice coil for feedback and a fairly simple PID control circuit. Flattening the response was easy; achieving low distortion took some time and tweaking of parameters, and I ultimately had to include power sensing, not just voltage sensing, in the control circuit. Probably should have patented it but I was just playing around. I still have the circuit, built into an old box, but now have more funds and much less time for tinkering, so Rythmik filled a need with much better performance for the price than the other subs I heard (Velodyne, B&W, Paradigm; did not try Hsu this time around). My limited discussions with Brian lead me to believe he has taken the earlier work much further in developing his servo control circuit, and the sound proves it. At least for me.

Just thought I'd share... BTW, I have been a design engineer (EE) for decades, and most of the best ideas I've had or seen were either never patented, or patented years after reduction to practice, in the interest of keeping trade secrets. YMMV - Don

Thanks again guys.

Isn't the FV15 listed at 2 prices, $999 for DS1501 driver and $1049 for DS1505 driver?

Yes, you are right. Brian did it last night.

glad I'm not losing my mind because I could have sworn I didnt see those options the last 300 times I've been at that page.

P.S. And I assume the upgraded driver serves to provide an ever so slightly larger "safety net" for high volumes?

Without enough info many things MAY BE possible, so why assume the worst? couldn't the improvement also be huge?

It appears a posting or two of yours was removed, correct? This is a Rythmik dedicated thread and so in that sense it is Brian's place. I was brought up to never disrespect someone in their own house. You can inquire and you can disagree but doing so in a respectful manner will get you the information you seek and being open to what someone else is saying will gain you knowledge. An old math teacher of mine was fond of saying "Its because you don't know what you don't know"... it took me years to understand the wisdom in what he was saying.



Brian... thanks for the explanations, I will probably get back to you by PM for further discussion when you have the time.

Is there any benefit or loss with using the DS1505 in the F15?

Hello, everyone! Thinking about getting a FV-15 HP for a 2600 cu ft. room that opens up into a staircase, and open area. I already have an Outlaw LFM 1-EX, and I'm thinking should I get another, or sell it and get the bigger sub. I feel the Outlaw is nearing it's output limits for my listening preferences (port chuffing, occassional bottom out)I'm 70% movies, 30% music. I'd like to hear your opinions...

So there really isn't much of a gain using the 1505 over the 1501 in the F15. Is there any loss, if even minimal, what would it be? I know I asked for the 1505 for the silver cone, I can handle the truth even if there is a little loss.

EDIT: If you can come anywhere as close in quality with a speaker design as your subwoofers... you should start building and selling. I'd be a customer.

Any Plans to utilize the DS1510 in a dual sealed design like the F25? I would assume this would mean use of a new more powerful amp?

Like the power of two of the 600 watt amps. I bet than would be bada$$.

Hi, I noticed most of the subs seem to be on back order on the rythmik site. Any idea when they will come back in stock ? I am looking for an F12..

Thanks..

Which model do you use?

And speaking of SPL, we watched Tron:Legacy last night and between the effects and Daft Punk my F12 was contributing to peaks in excess of 110 dB (dynamic range ~ 50dB) with profoundly palpable LFE. And I thought Unstoppable was the LFE champ.

Quite the follow-up to Saint-Saëns Symphonie No. 3 "avec orgue" which, by the way, sounds just peachy.

I know what you mean about both of those movies. With Unstoppable, it felt like the train was in the room, everything was vibrating as if the train were literally passing by... and there were a LOT of speeding train scenes with powerful LFE to match. Then last night we watch Tron and those "carriers" especially set off the same strong vibrations along with explosions, etc. Both movies have got a ton of visceral bass effects.

Brian, would it be more than 2 to 3 months away or more like 6 to 9 months away? Any estimate on what the price increase might be at this time on the high power version? I'm planning on getting a f25 for my 2 channel system (90% music 10% movies); I'm a patient man and I keep my equipments for a long time because I choose them very carefully.

What about idiot proof? I think that would be more my speed, for the first go around at least. I definitely am going have to look into the CI kits, because frankly I see other people rave about them. I, personally, would just worry that I could mess one up without knowing it, thinking "that's just how it is suppose to sound".

I really don't see myself being able to not try different subwoofers out. I don't think I can just go with one and that be it. I would be too curious to hear what other subs sound like. Or at least the difference between vented and sealed.

To me that is where the diy CI of Rythmik comes in as very interesting.

I kind of think I should go vented now and then maybe try my hand at some of the CI sealed stuff later. But I do just wonder how "fool proof" it really is..ha ha.

quite frankly, that offer shocks me...major, major points in my book.



For the FV15, whats the estimated shipping time (from order placement to delivery) to Winston-Salem, NC 27103?

I am anxiously awaiting to make an order for a paid upgrade. Just need a couple of 1510 drivers and 600w amps Being without a sub is harder than I thought. My wife is getting upset at me because I don't want to watch any movies untill I get the subs. Yes I am still watching the movies, just whining a bit.