Question: High Level vs unbalanced RCA input on Subwoofers?

Joey_V

Can someone elaborate either theory or experience with either input on subwoofers? I am looking at pure 2 channel subwoofing.

Thx

EndersShadow

Read this thread

Conradicles

I experienced better sound quality with high level several times on my journey.

Joey_V

EndersShadow wrote: »

Read this thread

This is the one I want to touch on.

audiomagnate wrote: »

1.The small amount of phase shift introduced by the main amp can be easily replicated using DSP.

2. Paul implies this technique should be used even when the main amp is a tube amp. Output transformers are anathema to deep bass. Taking this damaged signal and passing it on to your sub(s) is definitely NOT a good idea.

3. Paul believes that a passive interconnect is more degrading to sound than an amplifier. I don't.

Paul has another unusual sub hookup procedure that I happen to agree with under certain circumstances. He likes to run the mains full range, i.e. without a low pass filter. If your main speakers go deep and power handling isn't an issue this is a great idea. It's the same as using multiple subs to smooth out room nodes.

Is High level a better purer signal?

Is high level input a "faster" input? Meaning the sub will have less delay?

WLDock

What preamp are you using Joey? Does it have any bass management?

IMO, it doesn't matter if one has a $100K 2 ch rig or a $5K HT rig. The best sub integration is the one that places the sub in the best sounding location and there's some DSP room correction in the mix. Subs are SO room dependent ESPECIALLY for a high end 2 channel music system. Getting the bass blend and weight right, might require some tools if one used high level or low level inputs.

The high level vs. low level argument dust has not settled. Then there is the argument about letting the mains roll off naturally or adding in a high pass filter. The "purist" don't want anything extra in the signal chain, and so on, and so on......

These should be a good start at reopening that can of worms:

http://soundoctor.com/whitepapers/subs.htm

https://www.psaudio.com/askpaul/the-best-way-to-connect-a-subwoofer/

Joey_V

I am using Cary SLP05 which does not have bass mgmt, essentially I would be using one of the unused outputs from the pre into the subwoofer.

Or go hi level and hook it from the speaker terminal end or the amp section.

Looking at JL Gotham or Rel 25.

WLDock

Dude, if you go Gotham thats easy. Just use the preout and use the room correction.
You still need to select the best location however, and treatments.

Done!

F1nut

Joey_V wrote: »

I am using Cary SLP05 which does not have bass mgmt, essentially I would be using one of the unused outputs from the pre into the subwoofer.

Or go hi level and hook it from the speaker terminal end or the amp section.

Looking at JL Gotham or Rel 25.

I played with high (speaker) level and low (rca) level connections on my 2 channel sub. High level always sounded a bit better, so that's what I use. Velodyne, REL and Rythmik still come with high level, but unfortunately most don't.

This is one bad a$$ sub that should be on your list. http://velodyneacoustics.com/subwoofers/digital-drive-plus-18.html

WLDock

Also, that Gotham is a truck load of cash. Two Fathoms over one Gotham would allow you to smooth the bass around the room.

http://www.acousticfrontiers.com/jl-audio-fathom-v2-digital-automatic-room-optimization-daro-review

Further, if you dare to go outside of the box a bit...given you are looking at a $13K subwoofer, I would hope you are considering ALL options.

The legendary TC Sounds LMS-Ultra 5800 was the sub that measured lower distortion than the Fathom subwoofer. There's a fellow that found the Stereo Integrity HS-24 MKIII 24″ SUBWOOFER to be right on par in terms of accuracy.
https://www.diyaudio.com/forums/subwoofers/276968-favorite-subwoofer-drivers-6.html#post4781384

The sub in an 8 cu ft sealed enclosure has the displacement of 3-4 18" subs. Two of these, mated with some fancy veneer cabinets to match your mains, made by your local cabinet maker and a Dirac room correction unit, amps, etc. would be the ultimate bass system that could take on anything out there.


Here's one example:

https://www.canuckaudiomart.com/details/649302386-custom-monster-24-4000w-sealed-subwoofer/


https://stereointegrity.com/product/hs24-24-subwoofer/
https://www.data-bass.com/data?page=driver&id=56
https://www.hometheatershack.com/forums/sealed-subwoofer-build-projects/93273-stereo-integrity-hs-24-a.html#post916025
https://www.diysoundgroup.com/sealed-24-cabinet.html

Emerald Physics / Underwood HiFi debuted their $9800 open baffle version of it at AXPONA as the ultimate accurate sub for large panel speakers like Magnepan and MartinLogan.

https://www.audioholics.com/tower-speaker-reviews/axpona-over-6-000
https://www.emeraldphysics.com/category-overview/subwoofers

mikeyb128

I’m not exaggerating when I say I spent at least 30 hours integrating my JL into my two channel system using interconnects from my preamp. I followed the Sub Set up recommendations on RELs website and I was able to dial the sub seemless into my system using high level inputs from the amp. I run my JL from the 4 ohm binding posts on my tube amp. I built special cables using military surplus twisted, shielded silver wire, with furutech gold spades, soldered with silver solder. I run my mains full range with the little monster JL, cross over set at 40ish HZ.

For the best blend high level is king. But I guess fancy DSPs built into subs these days correct for that.

mikeyb128

Using the High Level input is always the best option. Using the High Level Input, instead of the Low Level Input, and connecting to the speaker output terminals of your amplifier is one of the unique secrets of REL’s success. When using the High Level input, your REL is fed the same signal that your main speakers are receiving. When connecting to the High Level input on the REL from the amplifier, you capture the sonic signature of your main system, including the tonal balance and timing cues of the entire electronics chain.

Joey_V

Hey Guys,

Thx for the DD18+ tip Jesse, do you know if that takes hi level inputs?

WLD and Mikey - I was thinking I could do a single gotham for now, position it wherever I need it or maybe even in the middle between the two speakers and room correct it. I could also fathom (pun intended) getting two JL113 and a CR1 as well, but I would probably rather get the Gotham use it singly and then save up for a 2nd.

There is a Rel that I am interested in. It is the ONLY Rel sub with room correct/dual parametrics that John Hunter says is sufficient to smooth out room response.

It is the Rel No 25. I could start with 1 then bridge out to 2 later on.

https://rel.net/product-category/reference-series/

The Rel G1mk2 does not have any room correct which kills it for me.

F1nut

Thx for the DD18+ tip Jesse, do you know if that takes hi level inputs?

Absolutely and it has a calibration program. Comes with its own high quality mic and stuff.

WLDock

Joey_V wrote: »

WLD and Mikey - I would probably rather get the Gotham use it singly and then save up for a 2nd.
It is the Rel No 25. I could start with 1 then bridge out to 2 later on.

Man, I guess you are set at dropping some serious coin on JL , Rel or two.

Yeah, the idea of clean output from a DIY 24" sub is a bit of a stretch for some in the 2 ch crowd. However, there are some REALLY good subs out there. One can get 2-3 Rythmik F18's for the price of a single No. 25 or 4-5 for the cost of a single Gotham.

The F18 is AWESOME! They are touting lower distortion and equal or more output than the DD18+! ($1850 in Piano black)
http://www.rythmikaudio.com/F18.html

Test & Measurements
https://data-bass.com/data?page=system&id=145

Rythmik Audio wrote:

The independent test lab site www.data-bass.com has published the max distortion numbers for F18. The F18 has lower distortion and yet more output than Velodyne DD18+ for 1/3 of the price. In addition, the test results also include the impulse response of 18hz high damping which shows minimal ringing, a testament of F18 articulation bass sound.

And in a Dirac Live unit for room correction - https://www.minidsp.com/products/dirac-series/ddrc-24

Thorton

Depending on the room size, how much low end your looking to fill-in and the quality of the gear you already own; if it was me, I’d buy 2. I believe it’s just a lot easier for seamless integration, placement options and achieving the low frequencies with 2. I also recommend something like REW to validate what your hearing. REW makes the placement time and optimization so much easier and faster. In addition, less DSP will be needed.

One may do it but I believe multiples are easier. Good luck and enjoy!

F1nut

The Rythmik is a solid suggestion. The reason I like the Velodyne is the front display and remote control capability, which I've found useful.

mantis

WLDock wrote: »

What preamp are you using Joey? Does it have any bass management?

IMO, it doesn't matter if one has a $100K 2 ch rig or a $5K HT rig. The best sub integration is the one that places the sub in the best sounding location and there's some DSP room correction in the mix. Subs are SO room dependent ESPECIALLY for a high end 2 channel music system. Getting the bass blend and weight right, might require some tools if one used high level or low level inputs.

The high level vs. low level argument dust has not settled. Then there is the argument about letting the mains roll off naturally or adding in a high pass filter. The "purist" don't want anything extra in the signal chain, and so on, and so on......

These should be a good start at reopening that can of worms:

http://soundoctor.com/whitepapers/subs.htm

https://www.psaudio.com/askpaul/the-best-way-to-connect-a-subwoofer/

I can clear the dust here which is easy to do IF you actually have experience setting up subwoofer in different rooms.
As you mentioned a subwoofer is an integration into ones living space. It pressurizes the space to recreate bass. The issue usually one doesn't have the proper amount of space to complete lower frequencies. So what you end up with is delayed signals which slap you after they bounce around in the room or intill completion of the wave.

So with all that being said if your running a 2 channel system you should strongly consider High level inputs which is speaker level. Line level will also work but your missing something most on the internet without true experience do. It's the interaction with the way the given amp your using reacts to your speakers. By placing the subwoofer in line your now taking sonic ques from the amp not just the source line level signal. The amp has it's own ability to be dynamic and recreating those peaks can be very different with a line level signal going to the amp and to the subwoofer. But with using speaker level the internal amp of the subwoofer tracks the dynamics of the amp and better blends with the main channel speakers. This is why many will claim hearing a sonic difference for the better using high level over using line level out of the preamp.
Without experiencing this yourself, this is all nonsense I'm babbling to the untrained.

F1nut

Dan, you and I don't agree on much, but you nailed that one!

Joey_V

Thx fellas

Velodyne DD+ vs Rel... that’s gonna be the question if we isolate subs that do hi level.

WLDock

mantis wrote: »

I can clear the dust here which is easy to do IF you actually have experience setting up subwoofer in different rooms.
As you mentioned a subwoofer is an integration into ones living space. It pressurizes the space to recreate bass. The issue usually one doesn't have the proper amount of space to complete lower frequencies. So what you end up with is delayed signals which slap you after they bounce around in the room or intill completion of the wave.

Without experiencing this yourself, this is all nonsense I'm babbling to the untrained.

Everyone here has their own experiences. Mine starting with actually playing music and then later the pursuit of stereophonic sound with much trial and error along the way. No I never worked in or owned an audio store or owned a $50K-$100K stereo system. However, I've ALWAYS loved music and have an ear for good sound.

As a kid in the 70's-80's I learned about room interaction and response trying to get my bass drum to sound good in different spaces. Later years I learned even more about acoustics playing in different types of bands in all types of venues. Setting up instruments and adjusting PA systems, etc. There's low frequency content coming from live instruments rather it be an acoustic jazz trio or a large orchestra. I've played in bedroom sized rooms as well as 100,000 seat stadiums.

Later years Tom Nousaine, and others taught me a little something about subwoofers. While Richard Clark and David Navone taught me a little bit about speaker level inputs driving amps. My first subwoofers for my car and 2 ch home system were raw sub drivers I ordered from Madisound. In both scenarios the subs were connected using passive crossovers driven by the same amp driving the main speakers. In my car I had a three-way system with two subs, two mids, and to tweeters using custom passive components driven by a single amp.

The Lucio Proni / JL Audio SQ Ford Mustang was the inspiration:

http://www.caraudiojunkies.com/showthread.php?1254-Lucio-Proni-1987-Mustang-GT-1990-CSR

I've ALWAYS been a DIY'er, tinkerer that likes to experiment and do things with my hands. I've learned that I preferred a dry low Q type of sub bass sound that does not bring attention to the sub or its location. I didn't start using preamp inputs to feed a sub until I put together a home theater system. I've even been asked before by an auto engineer friend to lend my ears and expertise on an OEM sub integration truck project he was working on.

It makes sense for someone with a high end full range system like Joey to consider speaker level inputs to drive his subs. He has very resolving equipment and is more likely to pick up on the benefits. However, given the wide range of preamps, amplifiers out there its very possible that there are preamp driven subs that can sound good and resolving. Unless one has done an A-B test of the Rel No. 25 vs. the Gotham connected to his system comparing both line level and speaker level inputs how can one really know the outcome? Everyone's experiences vary and some have not been able to hear a difference between the two.

Using this same "purist" logic the ultimate matched signal setup would to use identical amps / Amp manufacture for both the mains and sub fed by preamp signals. Mate this with an ultimate low distortion mechanical marvel like that 24" monster that I posted. However, many steer clear of subs all together or they opt for options like the REL, and JL. Why is that? Are the "purist" really getting their money's worth going this route?

There are always compromises in this hobby. There is no one empirical path to the audio holly grail that is going to work for everyone. So, respect the path of others and stay humble and enjoy the music because that's what its all about!

WLDock

Joey_V wrote: »

Thx fellas
Velodyne DD+ vs Rel... that’s gonna be the question if we isolate subs that do hi level.

If you are even interested, Rythmik has their custom installation products and might be able to come up with something that has speaker level inputs. Some of their amps have them and some don't. Their new nCore higher power amps seem to not have them but who knows what they have to offer in their arsenal. Also, Salk Sound offeres customer versions of their subs and seems to always be up for a challenge. So, you might be able to get two custom made subs for the coast of one off the shelf Rel or JL. Reach out to them if you are after a good value for the money.

daddyjt

F1nut wrote: »

Joey_V wrote: »

I am using Cary SLP05 which does not have bass mgmt, essentially I would be using one of the unused outputs from the pre into the subwoofer.

Or go hi level and hook it from the speaker terminal end or the amp section.

Looking at JL Gotham or Rel 25.

This is one bad a$$ sub that should be on your list. http://velodyneacoustics.com/subwoofers/digital-drive-plus-18.html

I whole-heartedly agree with this recommendation. I am now the fortunate owner of two (2) DD18 subs and a DD12. The servo control and GUI allow for infinite adjustment and flexibility of every aspect of the sub, including an 8 band parametric eq. The supplied microphone and RTA program show exactly what affect your adjustments are having.

I have been spoiled to the point that I would not consider a sub that did not incorporate servo control - I feel it truly indispensable in a quality sub, especially for 2ch music.

Just my .02

WLDock

Actually, the DD18+ might be what you are after if a deal can be had in the $3500 range each. http://www.newaudiovideo.com/index.php?main_page=product_info&products_id=9561

Given it has the auto EQ built in as well as speaker level inputs. Even if the Rythmik did have speaker level inputs most of the room correction devices available only accept preamp inputs. It would complicate things but I'm sure there is a work around. Internet direct subs like the F18 just win the price to performance war over and over again. The F18 numbers compared to the DD18+ makes the Velo look waay overpriced.
https://data-bass.com/data?page=system&id=145

The REL choice would be a personal thing with the brand or maybe you decide to buy one of each and decide on your own which you like the best.

Interesting read you might like if you haven't seen it.

http://sunnyaudiovideo.com/sunny-s-blog/rel-no.25-subwoofer-article

https://www.whatsbestforum.com/threads/whats-the-best-subwoofer-rel-jl-audio-velodyne-wilson-something-else.8668/

joecoulson

Prob on the bottom here with the catfish but I recently hooked up the SVS with XLR’s and love the stereo integration it offered. The +6db was easy to balance and using HT bypass I lost the pure LFE but I don’t regret for the 2.1 listening.

Joey_V

I will look at these DD+ further

Servo and full correction are pluses (no pun intended)