opinions wanted on subwoofers

[Nick B]

Lots more to assimilate.... 😀  I've been using eq to decrease bass in 10 hz increments from 50 down. Fuller midrange...male vocal... at least on the first song I attempted

Decrease? 

A member here who's been after me for a few years to get subs indicated that if I take a bit of the LF load off the 7" JMR driver, it will improve the mids and treble. That's what I was testing. As I've never used software like MUSE to try these tests, I was testing from 500 hz down and also boosting a few areas between 60-100 as well.

My purpose in adding subs is more to improve mid and treble presentation, rather than only improve LF. I don't listen to the lower/lowest frequency range all that much.

[Nick B]

Still up in Cedar.
Scotty

Happy for you you're not exposed to 115 degree heat 🥵

[Nick B]

@nick b

please download and play this. already converted to wav for your convenience

Mickey Hart, Airto Moreira & Flora Purim - Gates of Dafos -this is a remaster and taken from very high quality vinyl...16/44 pcm

https://myaccount.dropsend.com/file/783b693a17206081

Best.

Hal

Thanks, Hal. Will get this into my music folder to play via Roon

[Nick B]

If you are trying to setup a subwoofer, I would recommend Room EQ Wizard to help with the process. 

Runs on most computer platforms and with an inexpensive measurement mic, like a Dayton Audio iMM-6 or iMM-6S calibrated omni mic and TRRS cable, you can make very accurate measurements at your listening position.   

A lot of users out there for help, so that is why I recommend it.  You can even use REW to generate Parametric EQ data for the room for bass management.

Have Room EQ on Mac laptop, although haven't used it yet. Still thinking about which subs, will adding improve mids, highs soundstage enough to go down this road....

[Nick B]

If you're up for it, you can make a very simple high-pass filter (passive) that you place before the main amp:

https://www.audiocircle.com/index.php?topic=181310.0

Thanks tl. Since I moved, I have yet to find a number of things which includes my soldering iron. One of the guys here suggested this device....
https://www.parts-express.com/FMOD-Crossover-Pair-50-Hz-High-Pass-266-270?quantity=1
I would be attaching it to the XLR adapter at the amp.

I have no direct experience with those Harrison filters, but I have read comments over the years that they noticeably degrade the signal.  FWIW.  I would have more confidence in the Danny Richie / GR Research stuff that I linked.

Dave expressed the same reservations about the quality of the Harrison filters

[Nick B]

As if you needed another opinion...
I wouldn't get so hung up on the high pass filter- I understand what you want to use it for, but the easier and simpler solution is to run the speakers full range, and blend the sub in. You may find the sound as such is what you're listening for.
Of course, ideally, you'd need a sub with speaker level inputs. The RSL sub mentioned has them, as do many others.
I looked up your speakers, and the reviews say it has a 7" woofer, which isn't all that tiny. Unless it's a deceiving photo, your room doesn't seem overly large either, maybe mitigating the need to relieve your mains of full range duty.
Either way, I hope you quell your audio nervosa.

Jim,

Opinions are welcome. Yes, it's a 7" driver and I was wondering about the necessity. But...there are wise and much more experienced guys than me who feel adding subs improves the overall presentation to make it worth the effort and expense. I have no idea, so I'm open to information and opinions.

I have an open floor plan. Facing the speakers, the entire area to my right is open to the dining room and kitchen. There are none and won't be any room dividers. I had a similar setup in my previous home where my system was based toward the left wall (facing forward). How this kind of a floor plan affects room acoustics I have no idea. Maybe some day, in a different house, I'll be able to have a room dedicated solely for audio.

[_Scotty_]

Nick, I don't know if this bears repeating or not but if I understand the Starkrimson Ultra amp design, it is a balanced output design where both negative and positive terminals are hot and it wouldn't be a good day
if it's speaker outputs were connected to the speaker level inputs of a subwoofer.
The magic smoke might escape from two devices simultaneously.
Apologies if this comment is redundant.
Scotty

[Nick B]

Nick, I don't know if this bears repeating or not but if I understand the Starkrimson Ultra amp design, it is a balanced output design where both negative and positive terminals are hot and it wouldn't be a good day
if it's speaker outputs were connected to the speaker level inputs of a subwoofer.
The magic smoke might escape from two devices simultaneously.
Apologies if this comment is redundant.
Scotty

Scotty,

As i'm not a technically knowledgeable guy, all this bears repeating, so thank you! Jack has privately mentioned the problem with speaker connections and Class D amps. The subs I'm focusing in on are the RSL Speedwoofer Mk II which have speaker and line connections. The Speedwoofers are 10" which should be just fine for what I'm trying to accomplish. I also sent Leo at Orchard Audio an email tonight. Jack and Dave both recommended the RSL and it was my first choice as well...$449 each and shipping included. I'm 96.4% sure I'll be ordering these shortly 😉

[GDHAL]

Editorial comment:

About a year ago, at his suggestion and goodwill, an audio club member who swears by and uses a balanced power transformer, lent me one. I forget the model, but it was not a very high model as these things go. I could have purchased it from him for $500. There are some that are north of $5000.

I heard an immediately obvious *difference* in the sound. Some, like this audio club member, swear by it and only use balanced power.

I then found out, from two different manufacturers, one being Golden Ear (and I recommended their subwoofer herein this thread) that if one uses balanced power, it will void their manufacturer warranty. Balanced power can also lead to the outer casing of an amplifier becoming "electric" to the touch.

I googled the technology and read 30 minutes of material about it. You could too, if you don't already know.

I'm trying to understand if balanced power is completely different than a balanced circuit. I think it is. With the OPs permission, I believe @_Scotty_ is an engineer, so I'd appreciate a brief explanation/clarification, provided it doesn't hijack this thread.

In any case, my editorial shall end by stating that in my system, the use of balanced power produces such a profound difference in the sound presentation, that if I were subjected to a blind test and asked which power is being used, I would be able to answer correctly one hundred percent of the time.

Best.

Hal

[_Scotty_]

The Starkrimson Ultra amp is a BTL or bridge tied load amplifier. Here are some links to explanations
of this type of amplifier design from simple to complex.
https://www.analog.com/en/design-center/glossary/bridge-tied_load.html

https://en.m.wikipedia.org/wiki/Bridged_and_paralleled_amplifiers

https://www.eeeguide.com/bridge-tied-load-amplifier/

I am not an engineer.
Scotty

[_Scotty_]

Mostly Off Topic Sidebar, ignore as desired.
As far balanced power VS plugging straight into the wall AC. The downside is that in most cases
the amplifier circuitry wants to see as low an impedance as the it can get near theoretical zero in regards to the AC supplied from the wall outlet.
Powercords, power filters and devices such as an Equatech all act to raise impedance.
If one looks at the rise time of a current spike waveform on its way from the wall to your amplifier
the peak of the waveform will be noticeably rounded off by the insertion of the power filter
and the Equatech. In the case of noise and damaging current spikes this is a good thing,
as far as meeting your amplifiers demands for high amounts of current for instantaneous
peaks in the music program, not so much.
This is a case of your milage may vary. It may be the cats' meow or not.
It may also prove useful for reducing circulating ground currents in equipment
where they are problematic. That would subject to trial and error testing during design.
It would be beneficial to solve those problems in the first place as they cause increased distortion
at the output of the circuit or device.
Scotty

[James Edward]

I too have an open floor plan- which makes any speaker placement an adventure. I went the bigger is better route to try and compensate for the bass leaking out of one open side of the room. That worked up to a point, then the other (left) side became boomy because there was just too much woofage.
I wound up with open baffle speakers which don't fight the room in the same way, but also don't provide much bass slam for my tastes. Hence the two subs. There're many controls on subs allowing you to tailor the sound for your room, not to mention all the DSP solutions that are common today. Maybe if I wasn't such a purist (or Luddite), I'd try them.
Getting a sub, and then a second one, has been a challenging but very rewarding pursuit.
Happy hunting.

[Nick B]

The Starkrimson Ultra amp is a BTL or bridge tied load amplifier. Here are some links to explanations
of this type of amplifier design from simple to complex.
https://www.analog.com/en/design-center/glossary/bridge-tied_load.html

https://en.m.wikipedia.org/wiki/Bridged_and_paralleled_amplifiers

https://www.eeeguide.com/bridge-tied-load-amplifier/

I am not an engineer.
Scotty

I contacted Leo at Orchard Audio and he recommended looking at the REL website for specifics on how to connect REL subs to Class D amps. Here's the link and what I copied from their website. He says his customers have done this with good results....

https://rel.net/blog/2017-12-27/how-to/connect-rel-class-d-gear/

"BLOG
Connecting Your REL Class-D: A Step-by-Step Guide for Optimal Sound

ToneAudio Product of the Year: 212SE
With so many new RELs finding homes this time of year, and many first-time owners running AV receivers which are increasingly migrating to Class D, we thought this was a perfect time to guide new owners through how to properly connect their new REL to a Class D amp or receiver.

Hot Tip:
If you pick up the receiver and it simply feels incredibly light compared to the boat anchor receiver you used to own, it's likely a Class D. Of course, you should still verify this with the manual or by contacting the manufacturer.

One of REL's great advantages over conventional subwoofers is our filter architecture and the precise way that we connect High Level. But different amplifier types require slightly different methods for connecting our High Level cable. We'll be looking at Class D amps and how best to connect your REL to this style of amplifier. Don't know if your amp or receiver is Class D? First, call the manufacturer and ask, explain why you are asking. We have had good results with almost every manufacturer except a certain Japanese manufacturer whose 4-letter name begins with S and ends with Y. Over 2 hours on repeat phone calls left us as frustrated as you will surely be with that experience.

The Problem:
So, why does a Class D amp require a different connection than a traditional Class A/B amp? There is something done to the ground plane that is unique in our experience. See, ground should be exactly what it sounds like—a return path of energy back into Mother Earth. For every action, there is an equal and opposite reaction and for every outflow of electrical energy, there must be a proper, full return of that energy back to earth.

Here's where Class D amps get weird (not all, but about 90% exhibit the anomaly I will describe next). The Black speaker terminals on the rear of your amp traditionally, and by electrical convention, mean Earth Ground. Zero ohms, zero Hz. Ground. But with most Class D amps, that Black-colored speaker terminal* is no longer ground. Worse, it actually references to a positive voltage that is significant. We consistently measure 10-15 volts ABOVE ground. In practical terms, if your REL were mistakenly connected to a Class D amp or receiver the input of the REL would eventually be burned out because it would be pulling 15 volts through a circuit designed to see zero voltage. Over some period of time—months or a few years, this unwelcome voltage will burn out the front end of your REL.

The Solution:
Fortunately, the solution turns out to be both easy and inexpensive—potentially no cost difference at all if your system is theater-based.

On the REL High Level cable go ahead and connect up the Red (R+) and the Yellow (L+) leads as usual. "Float" the Black wire (do not connect it to anything), in fact, snip off the portion that is pre-stripped and wrap it in electrical tape to avoid accidental shorting out later on.
Next, connect a long RCA-RCA interconnect from either an unused input on a preamp or receiver to the REL's .1/LFE input. Do this even if you have no interest in theater, you are creating an audio ground, nothing more. This is true for 2-channel systems, we are not using the .1 LFE input for anything more than to produce ground.
If you are running this in a theater system, you're done; run your usual .1/LFE cable and float the black wire and you're done.
*One final call out, NAD recently introduced two new integrated amplifiers. We would like to commend them for specifically choosing Blue for their "Non-Hot" speaker terminal. Rather than Red/Black, the Red/Blue scheme gets people wondering why the color is different.

Along with our friends at Peachtree Audio, the NAD folks also added an old-fashioned knurled chassis ground bolt which makes it even easier than we described to obtain true ground on this style of amp. We salute these customer-centric companies.

In the case of a chassis ground bolt like this, please DO connect the Black wire to this bolt. "


I will be contacting Joe Rodgers at RSL for his comments.

Nick

[Nick B]

I too have an open floor plan- which makes any speaker placement an adventure. I went the bigger is better route to try and compensate for the bass leaking out of one open side of the room. That worked up to a point, then the other (left) side became boomy because there was just too much woofage.
I wound up with open baffle speakers which don't fight the room in the same way, but also don't provide much bass slam for my tastes. Hence the two subs. There're many controls on subs allowing you to tailor the sound for your room, not to mention all the DSP solutions that are common today. Maybe if I wasn't such a purist (or Luddite), I'd try them.
Getting a sub, and then a second one, has been a challenging but very rewarding pursuit.
Happy hunting.

Well, it's been an adventure and a challenge to get to this point. As I know very little about all this, try to have an open, receptive mind and have some very smart, experienced and nice guys helping me, it should work out.

I think the RSL Speedwoofer 10 Mk II is a good choice for budget considerations and performance and will await what Joe Rodgers says as well.

[Jack]

The REL explanation applies to their subs that use Class AB amps and connecting them speaker level to Class D amps.  I know many people who followed those instructions with either Class D or differentially balanced amps that ended up with humming subs.  In your case if you want to connect the Speedwoofers to the Starkrimson Ultra via speaker level then you are connecting Class D to Class D. See what Joe says as I'm sure he has dealt with it before.  Easiest way in your case is obviously to connect the subs line level and avoid all the grounding issues.