PSA S1500 vs. Rythmik F15HP

[Roen]

Would love to see a comparison done on these two subs!

 

[rojo]

Hey @Roen, if you're interested in output, then a vented sub would be better. Do you have space limitations that would make you exclude the FV15HP and the V1500 from consideration?

 

[Roen]

I'm a music fan and wanted to buy a musically accurate sub vs. one that has more output.

Sent from my Pixel XL using Tapatalk

 

[BoredSysAdmin]

Intuition says that the servo on rythmic sub will result in less distortion on higher output levels.

 

[j_garcia]

I have heard the F12 not the F15, but it sounded really great with music. If/when my Epic goes south again since I can't get another amp for it, I will likely go with the F15HP or similar from them. That is not to take away from PSA at all either.

My Epic gives me the best of both worlds IMO, output and sealed performance. It would be akin to the S3000i from PSA. Epic is no more though.

 

[rojo]

I'm a music fan and wanted to buy a musically accurate sub vs. one that has more output.

Sent from my Pixel XL using Tapatalk

Sealed != more musical. Whether a sub is musical depends on several factors -- Qts of the driver, appropriate enclosure size and tuning, placement, room modes, source media quality, level matched integration into the rest of the system, and the list goes on. The most obvious inference you can reliably draw from comparing sealed to ported is that sealed is inefficient for sub bass. If anything, a properly tuned ported sub is more musical because output at a given spl requires a shallower excursion where the driver is more controlled, where its BL(x) has better symmetry, where there's lower harmonic distortion. Where's Dr. Carter when I need him?

But yeah, for musicality I'm inclined to agree with the other posters that servo > not servo.

 

[Roen]

Sealed != more musical. Whether a sub is musical depends on several factors -- Qts of the driver, appropriate enclosure size and tuning, placement, room modes, source media quality, level matched integration into the rest of the system, and the list goes on. The most obvious inference you can reliably draw from comparing sealed to ported is that sealed is inefficient for sub bass. If anything, a properly tuned ported sub is more musical because output at a given spl requires a shallower excursion where the driver is more controlled, where its BL(x) has better symmetry, where there's lower harmonic distortion. Where's Dr. Carter when I need him?

But yeah, for musicality I'm inclined to agree with the other posters that servo > not servo.

Are you positing that the S1500 is less musical than the V1500, or that the F15HP is less musical than the FV15HP?

I'm not comparing subs across different lines, I'm looking at 15" driver subs within the same brand and choosing, within the same brand and driver size, sealed over vented for musicality.

Or does this not apply?

If the posit is true, why would anyone ever buy a sealed model when a vented one exists, if the vented one is more musical AND produces greater output than an equivalently driver sized sealed sub?

If you're curious, my room is 1500 ft^3, so I imagine I'll get a ton of room gain.

 

[rojo]

Are you positing that the S1500 is less musical than the V1500, or that the F15HP is less musical than the FV15HP?

When cranked, yes, I think so.

I'm not comparing subs across different lines, I'm looking at 15" driver subs within the same brand and choosing, within the same brand and driver size, sealed over vented for musicality.

Or does this not apply?

Chat with Tom V. on his website and ask what he thinks. He's smarter than me.

If the posit is true, why would anyone ever buy a sealed model when a vented one exists, if the vented one is more musical AND produces greater output than an equivalently driver sized sealed sub?

Size restrictions? WAF?

If you're curious, my room is 1500 ft^3, so I imagine I'll get a ton of room gain.

You're probably right. Ultimately, I think you'll be pleased with any of the choices in this thread.

 

[Roen]

When cranked, yes, I think so.



Chat with Tom V. on his website and ask what he thinks. He's smarter than me.



Size restrictions? WAF?



You're probably right. Ultimately, I think you'll be pleased with any of the choices in this thread.

I had also thought that sealed when combined with room gain, had a more gradual roll off of sub bass vs. ported in the same room? Am I mistaken?

 

[speakerman39]

Roen, another sub that you might want to take a very good look at is the HSU ULS 15 MK2 inmho. I have owned both the S1500 and/or the ULS 15 MK2. It is true that I preferred the S1500 to the ULS 15 MK2, but they were very close in terms of performance. In fact, I ended up with dual S1500's as my preference is also on music. However, in the price range of the ULS 15 MK2 there is not much out there that can touch it inmho. Here is a link:

http://www.hsuresearch.com/products/uls-15mk2.html

All (3) of my subs were all B-stocks and worked perfectly. Might can save you some money. Good luck with your search! I also agree that the Rythmik is a serious contender.


Phil

 

[KEW]

I have both Rythmik E15HP's and PSA XS15se's. I listen primarily to music.
Quite honestly, I cannot tell a difference between them other than I think the Rythmik may go deeper for HT. But for music, I cannot tell the difference.

On the topic of sealed vs vented, I believe everything stated here is true, but I also believe that a sealed gives you a more natural frequency response after room gain is added.

Josh Ricci had this to say about the XS15se:

The basic frequency response shape with the low pass filter bypassed shows a response that is cleanly extended up to 200Hz and beyond, with a gently sloping low end that corners at 30Hz and appears to enter a sealed systems natural 12dB/octave roll off below that point. It should be a good match with the boost often seen in the low bass once placed in room.

So my contention is that most sealed subs (unless they have DSP to make them flat to 20Hz in an anechoic chamber) will be closer to flat down to 20Hz in room due to their natural roll-off.

I think it is a poor objective to design for flat in an anechoic chamber when you know you will use it in a normal residential room! Every vented sub I have noticed uses the port to tune for anechoically flat down to ~low 20's. That means they will be bass-heavy once you put them in room. The perception of this over-emphasized low bass in music is a lack of tightness. Of course, systems like Audyssey and miniDSP can allow you to correct/tune for this, but I believe it is best to shoot for having your in room response as flat as possible before applying room correction.

Lately, the good ID sub manufacturers have been adding ways to tune their products. Rythmik has always been one of the best products in this regard and I ended up with mine set to the least processing (which is essentially what the XS15se is). I also believe that the Rythmik has lower distortion levels when driven hard, but I never push mine that hard - well maybe on HT with an explosion, but distortion when reproducing an explosion is a bit of an oxymoron. I have no idea what a "clean" explosion sounds like!

The simple "Room Size" knob of the S1500 is a great way of allowing effective tuning without becoming an overly complicated array of options. I have a pair of S1500's, but I just unpacked them last week. I don't hear a difference between them or the XS15se or the E15HP. Bass is not too revealing and these 15" sealed subs have more in common than different. I'm sure they all measure different and I am certain that if you push them to their limits some significant differences will surface. But for my purposes, they are mostly interchangeable in that they provide good tight low frequency support for my speakers without calling attention to themselves!

That doesn't really answer your question, but hopefully it will help with your decision.
I should add that I mostly listen to jazz and progressive rock with a bit of classical and pop mixed in.
If you are into Dubstep, you might want that heavy bass!?

 

[shadyJ]

You will never see a head to head competition of these subs. Neither company is even interested in having their subs measured. Between these subs, I would go for the Rythmik, notwithstanding the servo technology (which I think might only make an audible difference at the extremes of excursion), I am sure they are using a higher-quality driver.

 

[William Lemmerhirt]

Imo, the sealed/ported debate is old news. Today we have much better drivers, and amp tech that provide much better control and that in turn makes better subs in general. To me the only reason to buy sealed is for size. I also feel the room gain, shallow roll off extension thing gets overstated. As noted, not to knock PSA, but I like rythmiks Kool-AId.

 

[KEW]

You will never see a head to head competition of these subs. Neither company is even interested in having their subs measured. Between these subs, I would go for the Rythmik, notwithstanding the servo technology (which I think might only make an audible difference at the extremes of excursion), I am sure they are using a higher-quality driver.

One feature of the servo design is it does not need as good of a driver nor as powerful of an amp to get equivalent performance.
What makes you sure that the Rythmik driver is higher-quality?
Given your acrimonious history with PSA, you should back that statement up with specifics.

 

[shadyJ]

One feature of the servo design is it does not need as good of a driver nor as powerful of an amp to get equivalent performance.
What makes you sure that the Rythmik driver is higher-quality?
Given your acrimonious history with PSA, you should back that statement up with specifics.

No offense, but I think you are quite wrong about the servo design somehow exceeding the limitations of the driver or power amplification. My guess is it can help maintain linearity where induction effects can take a toll, and it can slightly help maintain linearity as the driver begins to run into the effects of xmax excursions, but that is about it. It can't make the driver perform better than its mechanical limitations. Also keep in mind that there are trade-offs in all speaker design.

The Rythmik is plainly using a higher-performing driver. Compare Data-bass's measurements of the FV15HP to the XV30se. From my understanding, the 15" in the present PSA products is not dramatically different than the ones in the XV30se. For most of the subwoofer frequency band, the FV15HP is outperforming the XV30se and it is only using one DS1510 driver versus two of PSA's Lab15 variants. Granted, the Rythmik driver is being fed a bit more wattage, and it has a larger enclosure space for its one driver, but still, if the PSA drivers were on the level of the DS1510, that comparison would not be as close. A key to this is the distortion quantities, that lets know you know at what point the driver is being stressed. That Rythmik driver is pretty beastly.

 

[Roen]

I have both Rythmik E15HP's and PSA XS15se's. I listen primarily to music.
Quite honestly, I cannot tell a difference between them other than I think the Rythmik may go deeper for HT. But for music, I cannot tell the difference.

On the topic of sealed vs vented, I believe everything stated here is true, but I also believe that a sealed gives you a more natural frequency response after room gain is added.

Josh Ricci had this to say about the XS15se:


So my contention is that most sealed subs (unless they have DSP to make them flat to 20Hz in an anechoic chamber) will be closer to flat down to 20Hz in room due to their natural roll-off.

I think it is a poor objective to design for flat in an anechoic chamber when you know you will use it in a normal residential room! Every vented sub I have noticed uses the port to tune for anechoically flat down to ~low 20's. That means they will be bass-heavy once you put them in room. The perception of this over-emphasized low bass in music is a lack of tightness. Of course, systems like Audyssey and miniDSP can allow you to correct/tune for this, but I believe it is best to shoot for having your in room response as flat as possible before applying room correction.

Lately, the good ID sub manufacturers have been adding ways to tune their products. Rythmik has always been one of the best products in this regard and I ended up with mine set to the least processing (which is essentially what the XS15se is). I also believe that the Rythmik has lower distortion levels when driven hard, but I never push mine that hard - well maybe on HT with an explosion, but distortion when reproducing an explosion is a bit of an oxymoron. I have no idea what a "clean" explosion sounds like!

The simple "Room Size" knob of the S1500 is a great way of allowing effective tuning without becoming an overly complicated array of options. I have a pair of S1500's, but I just unpacked them last week. I don't hear a difference between them or the XS15se or the E15HP. Bass is not too revealing and these 15" sealed subs have more in common than different. I'm sure they all measure different and I am certain that if you push them to their limits some significant differences will surface. But for my purposes, they are mostly interchangeable in that they provide good tight low frequency support for my speakers without calling attention to themselves!

That doesn't really answer your question, but hopefully it will help with your decision.
I should add that I mostly listen to jazz and progressive rock with a bit of classical and pop mixed in.
If you are into Dubstep, you might want that heavy bass!?

Thanks Kurt!

Please let me how you feel about the S1500 as you start to utilize them more, and what the differences are to the XS15e (amp differences) and the E15HP.

 

[slipperybidness]

@Roen
I'm a happy owner of the F15HP, for the last several years! It is a BEAST of a sub! I bought the sealed Rythmik for 2 reasons: It was B-stock and Rythmik doesn't get B-stock very often, and the only place available in my home for a sub would not fit anything larger! I'm in an open floorplan home, FWIW.

My bro-in-law uses the FV15, and that is yet another beast! In raw output performance, the FV definitely beats my F15! Unfortunately, I have never had a chance to compare these side by side.

When I picked up my sub directly from Bryan at Rythmik, I did have a chance to talk to him a bit, see some raw drivers, etc. Those Rythmik 15" drivers look to be extremely well built and engineered. Bryan has dual degrees from USC: Electrical Engineering and Acoustical Engineering! He also personally designed those servo amps. For me, it's a no-brainer b/c Rythmik is a local business!

And, I have absolutely no experience with PSA.

 

[KEW]

No offense, but I think you are quite wrong about the servo design somehow exceeding the limitations of the driver or power amplification. My guess is it can help maintain linearity where induction effects can take a toll, and it can slightly help maintain linearity as the driver begins to run into the effects of xmax excursions, but that is about it. It can't make the driver perform better than its mechanical limitations. Also keep in mind that there are trade-offs in all speaker design.

But if the servo maintains linearity as the driver approaches xmax, isn't that an alternate approach to getting the performance of a higher quality driver? Obviously the mechanical limits are hard limits, but the ability to get a driver to behave optimally up to its mechanical limits via the design of the driver is an expensive proposition.
No driver behaves perfectly as it nears it's mechanical limits, servo is an alternative to spending more on driver quality or needing to go to a larger size.

Granted, the Rythmik driver is being fed a bit more wattage, and it has a larger enclosure space for its one driver, but still, if the PSA drivers were on the level of the DS1510, that comparison would not be as close. A key to this is the distortion quantities, that lets know you know at what point the driver is being stressed. That Rythmik driver is pretty beastly.

So you are concluding that the Rythmik driver is better (regardless of servo system) because of lower distortion when under stress.

However, Rythmik cites low distortion under stress as the primary (1st and 2nd) benefits of the servo mechanism.

A servo is essential in a subwoofer that aims to be true to the original. The benefits are clear:

No voice coil thermal-induced compression or distortions.

Spider and surround distortion reduced by 6 - 9 dB

Flat frequency response that is less dependent on T/S parameters.

Audiophile bass sound at an affordable price: articulate, tight, transparent, and well-defined bass

Applicable to all subwoofer configurations (including horns, dipole, infinite baffle and others)

Higher output (with better excursion utilization) for sealed, IB, and Dipole subs.

These benefits are all unique to a servo controlled subwoofer, and can't be achieved in a practical and affordable way in a conventional subwoofer.

Understand that I think Rythmik is an excellent product and do not believe they use crappy drivers. I just don't see how you can say that the end product indicates a better driver when the metrics you use for this evaluation are much of what Rythmik professes the servo to provide.

 

[shadyJ]

But if the servo maintains linearity as the driver approaches xmax, isn't that an alternate approach to getting the performance of a higher quality driver? Obviously the mechanical limits are hard limits, but the ability to get a driver to behave optimally up to its mechanical limits via the design of the driver is an expensive proposition.
No driver behaves perfectly as it nears it's mechanical limits, servo is an alternative to spending more on driver quality or needing to go to a larger size.


So you are concluding that the Rythmik driver is better (regardless of servo system) because of lower distortion when under stress.

However, Rythmik cites low distortion under stress as the primary (1st and 2nd) benefits of the servo mechanism.


Understand that I think Rythmik is an excellent product and do not believe they use crappy drivers. I just don't see how you can say that the end product indicates a better driver when the metrics you use for this evaluation are much of what Rythmik professes the servo to provide.

I would guess that any help that the servo system gives around xmax length excursions is slight. For example, if the suspension is starting to exert some tension on the inward stroke, a servo system might theoretically help to compensate for that. But once excursion has reached that far, it doesn't have much further to go. You can compensate for that a little bit, but in doing so you push the cone further in the direction that is already seeing significant tension. I think this would be true for motor-based excursion extremes where the coil is leaving the gap as well. The thing is, suspension tension and coil displacement are the two major causes of subwoofer driver distortion, and I don't see servo mechanisms making a huge difference there. I think the servo system does change the character of the sound when it is driven hard, and I believe I have heard these effects personally, but it wouldn't allow it much more linear stroke than the driver already has. Inductance can also be a problem, but a well-balanced driver design doesn't have to worry about that anyway.

Another thing to keep in mind is that it is Rythmik's responsibility to prove the effectiveness of their ideas. How would they do that? By taking two subs where they drivers are are as close to equal as possible, except one has a servo system in it and the other doesn't, and then showing the benefits of servo when you have a control subject. As far as I know, they have not done that, neither have Velodyne, Paradigm, Genesis, or any other servo system manufacturer. Until the benefits have been demonstrated in such a manner, any claims these manufacturers make should be approached with skepticism, as with so much else in audio.

As for compensating for thermal compression, I don't see that as a major advantage. In fact, it can be regarded as a disadvantage. So the coil is losing its magnetic strength because it is warming up (the permanent magnet and top plate also loses a bit of its magnetic strength as they warm up too), so how do you compensate for that? By inputting a lot more current than a normal system would see, thereby causing a more heat than normal. I trust I don't need to elaborate on the dangers here. The fact is, if you are running your system so hard that thermal compression affects the sound quality, the solution is either more subs or better subs, not shoving more wattage into a driver that is already suffering from thermal effects.

 

[KEW]

You are a smart guy, and your speculations have reasonable thought behind them; however, at the end of the day they are still speculations.
Somewhere I read a review where the reviewer discussed the servo system with Brian Ding and made the comment that the servo allowed a lesser driver to compete with better drivers. Unfortunately, I cannot find it to be able to better appraise the source.
The fact that they are very competitive in the ID sub market means they are somehow getting performance to offset the cost of adding the servo.

I would also point out that you chose the FV15HP to make the case against PSA, which is an amazing value and pretty well beats anything Hsu, SVS, or PSA have to offer.