accurate, distorion free sub for music

[Warpdrv]

The DTS-20 is -3 @ 150hz. While the curve isn't as smooth as a direct radiator, it will blend fine with an 80hz crossover, especially if your processor lets you go 4th order. EQ will be necessary to smooth out its response but once you do it should have no trouble blending with any speakers unless you listen reach the mains' limitations at higher volumes while it keeps going. Even ported subs will have resonances around this region - no sub should be playing this high at meaningful levels.

accurate, distorion free sub for music

His request - My limitations are 20" x 20" x 20" (or very close to it - certainly, smaller is better) for size/WAF, budget of $1,000 - $1,500 + shipping, and a slight preference for sealed (size).


Careful about suggesting this or other DTS's - I've seen some THD 3rd party measurements and they didn't look like something that I would be all that thrilled with... I'm waiting for them to be released publicly... They seem to be a great product with excellent output but have a semi rough response curve....


What is the room size here....?

 

[sholling]

I think Rythmik now has a version of the amp available that does not have this characteristic.

That may very well be but the above graph is linked to Rythmik's site and reflects what they currently have posted for the high output F15. Perhaps the new amp hasn't been released yet or hasn't been measured.

 

[cschang]

That may very well be but the above graph is linked to Rythmik's site and reflects what they currently have posted for the high output F15. Perhaps the new amp hasn't been released yet or hasn't been measured.

Yeah...the site doesn't have a lot of their current stuff.

 

[sholling]

Yeah...the site doesn't have a lot of their current stuff.

Maybe they need a good volunteer admin?

 

[ntrain42]

The PB13 Ultra is much more expensive and per Rythmik the 15" can't keep up output wise with the Hsu and actually suggested two for my application. It also (per discussions with Rythmik) the F15 falls off above 80hz which is what the charts show.

This is a very old plot, and the new Rythmik plate amps and xovers allow for upper extension beyond 120hz before rolling off.

The PB13 is "more expensive" but there are quite a few factors as to why, and it really has nothing to do with the quality of components used. For the price of ONE PB13 Ultra you can get 2 F15's. And 2 F15's will have quite a few advantages over a single PB13 Ultra that naturally running dual subs will bring. One being more even bass response in room. A second will be the ability to lower the gains on both subs reducing distortion and improving dynamic headroom. 2 Rythmiks will trump one PB13 everytime. The PB13's I previously owned had great output no question, but they were nowhere near as articulate with bass detail as my current Rythmik subs.

 

[ntrain42]

I think Rythmik now has a version of the amp or mod available that does not have this characteristic.

COrrect, the servo circuit I believe was modified in combination with the xover to allow higher frequency extension. Using full bandwidth pinknoise I am able to get ruler flat in room response with my RYthmiks from just under 20hz to just over 120hz before rolling off gently.

 

[ntrain42]

That may very well be but the above graph is linked to Rythmik's site and reflects what they currently have posted for the high output F15. Perhaps the new amp hasn't been released yet or hasn't been measured.

If there is one thing Rythmik(Brian) needs to do its update the website, it is severly outdated on the products, options and specs. Most of those graphs etc were based on 1st/2nd Gen products from 4-5 plus years ago. The new drivers and amp revisions I believe would technically be considered 4th gen.

 

[sholling]

If there is one thing Rythmik(Brian) needs to do its update the website, it is severly outdated on the products, options and specs. Most of those graphs etc were based on 1st/2nd Gen products from 4-5 plus years ago. The new drivers and amp revisions I believe would technically be considered 4th gen.

I'll take your word for it but when I spoke to Brian roughly 6 months ago he told me that 80hz was the recommended upper crossover point for the E15 and F15. The amp changes are since then?

 

[ntrain42]

I'll take your word for it but when I spoke to Brian roughly 6 months ago he told me that 80hz was the recommended upper crossover point for the E15 and F15. The amp changes are since then?

Brian is very quirky with his recommendations I find. But in the last 6-8 months he has made a number of changes to his plate amps, as they have had some modifications to the xover, limiter etc.

Using an RTA and pinknoise though and with the xover set to 120hz the sub is flat right up to that point rolling off at roughly 12db per octave past that point. In one of my HT setups I run all Kef XQ10's(smallest bookshelf of the XQ line using a 5.25" driver)with a pair of Rythmik D15SE's. I am able to run the sub over a full octave more than what I generally like to run. Due to the downfiring nature of the subs design and the ability to get phase and amplitude perfect I get no localization whatsoever and allow my small monitors to run at a much higher volume with very clean output. All of the bass sounds like it comes directly from them. Its something I have not been able to do with any of the past subs Ive owned or installed(and thats quite a few). In another setup I run a pair of F15HP subs with a pair of modified Kef XQ20's(They use a custom external passive xover and a reinforced and damped enclosure), those I run with a xover lowpass at 50hz as my XQ20's are able to extend down to 50hz solidly at the lower volume levels I use them for in a much smaller room.

The Rythmik subs are a true audiophile grade sub and the price cannot be beat. If you want serious output, just add another or a few as you can pick up a few of them for the price of one built by some of the mainstream mfg's.

Many people don't seem to understand that they are so reasonably priced is because its literally a one man operation, with no overhead cost(no warehouse,staff etc), no distributor markup, no retailer markup, no salesman commision, and very little if any advertising. Word of mouth alone on the performance on many forums is why these subs are really popular.

My new HT system which I am currently installing is using 8 DS1510 DIY Rythmik kits featuring the XLR 600 watt class H amps which will all be daisy chained together. Im hoping to have it finished within the next month finally.

 

[Warpdrv]

I'll take your word for it but when I spoke to Brian roughly 6 months ago he told me that 80hz was the recommended upper crossover point for the E15 and F15. The amp changes are since then?

That sure seems to be a drawback... Subs should at least play up to 200hz to mitigate any problems crossing over... and furthermore give far more options IMO...

 

[sholling]

That sure seems to be a drawback... Subs should at least play up to 200hz to mitigate any problems crossing over... and furthermore give far more options IMO...

When we were talking he was fairly convinced that 80hz for the 115" and ~100hz for the 12".

 

[cschang]

That sure seems to be a drawback... Subs should at least play up to 200hz to mitigate any problems crossing over... and furthermore give far more options IMO...

Brian really believes that crossing higher than 80-100hz is not a good idea.

 

[jp_over]

His request - My limitations are 20" x 20" x 20" (or very close to it - certainly, smaller is better) for size/WAF, budget of $1,000 - $1,500 + shipping, and a slight preference for sealed (size).


Careful about suggesting this or other DTS's - I've seen some THD 3rd party measurements and they didn't look like something that I would be all that thrilled with... I'm waiting for them to be released publicly... They seem to be a great product with excellent output but have a semi rough response curve....


What is the room size here....?

Warpdrv,

To answer your question:

"I have about 2500 cubic feet in the living room but it opens to the kitchen (upping the cubic feet quite a bit)."

By the way, I'm coming very close to a decision. Currently, it's down to the Rythmik F12 and the F15... not so much a price consideration, but trying to figure out which will provide higher audio quality. Since I don't regularly listen to ultra low hz stuff (pipe organ music or electronica), it might not even be an issue. Also, space is a close secondary consideration since I think it would be much easier to implement a 2nd F12...

F12 - 15-3/4"(W) x 15-3/4" (H ) x 17"(D)
F15 - 19"(W) x 19 " (H ) x 20 "(D)

Thanks again for all your input! Some might call me crazy for putting together a system "unheard" but such is the wealth of advice and experience here!

 

[ntrain42]

Warpdrv,

To answer your question:

"I have about 2500 cubic feet in the living room but it opens to the kitchen (upping the cubic feet quite a bit)."

By the way, I'm coming very close to a decision. Currently, it's down to the Rythmik F12 and the F15... not so much a price consideration, but trying to figure out which will provide higher audio quality. Since I don't regularly listen to ultra low hz stuff (pipe organ music or electronica), it might not even be an issue. Also, space is a close secondary consideration since I think it would be much easier to implement a 2nd F12...

F12 - 15-3/4"(W) x 15-3/4" (H ) x 17"(D)
F15 - 19"(W) x 19 " (H ) x 20 "(D)

Thanks again for all your input! Some might call me crazy for putting together a system "unheard" but such is the wealth of advice and experience here!

Bypass the F12 for the F15. I've demo'd the F12 and scrutinized it vs. the F15. The F12 offers absolutely nothing over the F15, even in the higher frequencies blending in with smaller mains. The F15 though gives you naturally an extra 2-4db of output over the F12 due to the cone size. The benefit of this is that the F15 will only need roughly half the power that the F12 does to get the same volume output. WHat does this mean? Low gain control, which means less distortion and higher natural headroom.

The question you should really ask yourself is do I do an F15, an F15HP or a D15SE? Personally based on what you have for a room/equipment Id be doing the F15HP.

 

[jcl]

Just a thought regarding the recommended crossover freq. - Rythmik's crossover recommendation might change based on the mated speakers ability to cover the bass freq. For the audibility of localization of the bass 80hz would be better, if the speakers can handle it. If the speakers cannot handle 80hz then a higher crossover would be necessary.

From Rythmik's site, on the F15 pages they show a second graph, specifically with the new PEQ amp and a much gentler drop off at the upper end of the range. It states "The new A370PEQ2 amplifier, now shipped standard with F15, has an additional low pass filter setting --LFE. It extends the upper end -3db extension to 200hz."

Fig 1.1 - F15 Frequency response chart in LFE low pass filter setting (only available in A370PEQ2 amp).

 

[Warpdrv]

Brian really believes that crossing higher than 80-100hz is not a good idea.

Thats kinda like a speaker builder producing a speaker with a more then adequate capability of playing down to 60hz putting in a HP filter so it will roll off at 100hz.... Is there something going on with the servo that effects the performance of the driver above 80hz...?

That may be his pref, but multiple subs in a single room will mitigate the concern for localization allowing for a higher crossover.... I let my room measurements determine what my crossover should be, as well as my taste in how much impact I get in the upper bass regions I want...

Not every room is the same, and cancellation with the long wavelengths can be an issue for some crossing over ONLY at those freq's... What if someone wants to mate some smaller bookshelves that don't play down to 80hz, with one of his subs, does that mean that they are told to go look elsewhere.... ?

 

[Warpdrv]

Warpdrv,

To answer your question:

"I have about 2500 cubic feet in the living room but it opens to the kitchen (upping the cubic feet quite a bit)."

By the way, I'm coming very close to a decision. Currently, it's down to the Rythmik F12 and the F15... not so much a price consideration, but trying to figure out which will provide higher audio quality. Since I don't regularly listen to ultra low hz stuff (pipe organ music or electronica), it might not even be an issue. Also, space is a close secondary consideration since I think it would be much easier to implement a 2nd F12...

F12 - 15-3/4"(W) x 15-3/4" (H ) x 17"(D)
F15 - 19"(W) x 19 " (H ) x 20 "(D)

Thanks again for all your input! Some might call me crazy for putting together a system "unheard" but such is the wealth of advice and experience here!

I will say that I have heard the D15SE on a few occasions at my house as well as at my friends, and it is a very nice product - smooth and accurate... Brian does make some nice sounding subs and I don't think you can go wrong with any of them....

In a room size such as yours (PUNY)... a pair of 12's would be awesome and likely give you all the output that you would need, but since you are shooting for HT and not just a 2 ch rig, I would shoot for the 15's as well, even a single 15" sub in that room should provide you with as much output as you need or want, with the ability to add a second down the line...

Personally, with my experience through many many subs, I prefer sealed and would never buy or build a ported sub.

Good luck with your decision...

 

[ntrain42]

Thats kinda like a speaker builder producing a speaker with a more then adequate capability of playing down to 60hz putting in a HP filter so it will roll off at 100hz.... Is there something going on with the servo that effects the performance of the driver above 80hz...?

That may be his pref, but multiple subs in a single room will mitigate the concern for localization allowing for a higher crossover.... I let my room measurements determine what my crossover should be, as well as my taste in how much impact I get in the upper bass regions I want...

Not every room is the same, and cancellation with the long wavelengths can be an issue for some crossing over ONLY at those freq's... What if someone wants to mate some smaller bookshelves that don't play down to 80hz, with one of his subs, does that mean that they are told to go look elsewhere.... ?

Read post #35 above. Again the new gen. subs extend well above 120hz, they changed the xover and servo circuit on em in the latest gen.

 

[Warpdrv]

I read the post, that doesn't change the problem with the old amp or the justification of the 60-80hz only xover.

Plus those amps aren't avail to late feb.

 

[jp_over]

Warpdrv,

"In a room size such as yours ([modest] paraphrase, )... a pair of 12's would be awesome and likely give you all the output that you would need, but since you are shooting for HT and not just a 2 ch rig, I would shoot for the 15's as well, even a single 15" sub in that room should provide you with as much output as you need or want, with the ability to add a second down the line..."

Minor correction: My main goal is accurate, musical bass, I only have a center for TV dialogue. Whatever bass gets produced during movies is fine; definitely not a great concern for my application.

I think that F15HP idea is OK (of note, just found out matte black won't be available until March for this model) but I'd much rather add 1 or even 2 more F15s if I needed it (props to Dr. Geddes for introducing me to multiple subs).

Also, I looked at the D15SE but it's only recommended for concrete subfloors per the company (asked about it via e-mail). I just can't be sure my next house will have this feature so I think a non-down firing sub would provide more flexibility.

To all who have posted, thanks for all the education and insight thus far!