Subwoofer gurus, can you spare a minute?

The Rythmik L12 and LV12R are priced similarly to the old Outlaw LFM-1 Plus and LFM-1 EX. Owning both an LV12R and an LFM-1 EX, I know that in most circumstances I prefer the Outlaw, and that includes for playback of 2, 4 and 5.1 channel music.

 

Good catch! My bad as in all honesty I can't recall which LFM-1 version I had. Bought the first F12SE used (great price) and the second was B Stock direct from Rythmik. The F12SE is definitely more expensive than the LFM-1. But the performance in my system is well worth the additional cost IMO. The single F12SE was better with stereo and multichannel music over the LFM-1. But without a doubt the LFM-1 is definitely an excellent sub!

 

Another case of "you get what you pay for"!

 

Definitely! Both the Outlaw and the Rythmik are well worth their cost.

 

The manufacturer has to write it to the abilities of the unit they are trying to market. The reality is that a phase adjustment by degree is necessary to seamlessly integrate a sub. Most speakers are not phase coherent. Only a rare few are. That means that within a main speaker the phase is different between where the mids cross over to woofers versus the phase angle in the lower bass region where you will cross over to the sub. So picking absolute polarity based on the mids or wiring means nothing to the phase of the woofer because it will be different. You won't know the phase at the main speaker's bass output without measuring.

Whenever you add crossover parts, caps, resisters, inductors, you mess with phase. Throw in a subwoofer variable crossover and you end up with variable phase shift depending on the setting of the sub's crossover. When you change the crossover point on the sub it will shift the subs phase.

To counteract these two issues the sub needs to have a variable phase adjustment or it will not able to integrate seamlessly. It me be good enough for many by ear but it won't hold up to graphing of the room's response.

 

Duly noted and points well taken. My set-up doesn't use any crossover between mains & sub. I run my main speakers full range. Magnepan 3.7i bass gradually starts rolling off around 40 Hz. I set my Hsu subwoofer's crossover frequency to cut off at around 40 to 42 Hz. There's no perceptible overlap, and the low bass extension is so good that the subwoofer achieves seamless integration (to my ears). Only one recording has ever made me question phase in this configuration, and I've come to the conclusion that it's a low bass drum recording anomaly with that one particular song.

I haven't considered graphing my listening room, but for those having difficulty integrating their speakers to room acoustics that's excellent advice.


Cat

 

Firstly, I'm shocked not to find a recent review of Magnepan speakers by Stereophile.

Here is a perfect example of what I was trying to describe. On the old 3.6R panels the midrange is in the opposite polarity from the woofer and tweeter.
In the graph you see the tweeter and woofer fire in positive polarity wile the midrange goes in reverse. It also looks like the woofer fires later than the tweeter and the midrange sections. That would be a phase shift in the woofer section.
Something like this happens on almost speakers. Rarely are they completely aligned.

Here is an example of how the graph should look for a time and phase coherent speaker, Vandersteen Treo. The graph shows all frequencies firing at the same time and in the same phase.
Thanks to Stereophile for making these graphs available.

 

Is it possible that two different subwoofer manufacturers could share differing viewpoints (vis-a-vis this question of high vs. line level inputs) and then construct their equipment to take maximum advantage of what they feel is the better option?

Put another way, is it possible that REL subs could be optimized to receive high level inputs, while Rythmik or some other subwoofer company’s hardware topology could be optimized to receive line level or LFE inputs?

And by all means, avanti, please read that in the tone of one being inquisitive rather than confrontational.

 

Trying to compare dipole speakers (planner magnetics & electrostatics) with more conventional box speakers is apples and orangoutangs. While time and phase measurements may look good on graph paper, I'm more concerned with musicality and aural perception in real life application. Hearing is believing; all else is incoherent.

It has been reputed for quite awhile that a less than friendly posture exists between Stereophile and Magneplanar over test methodology and real world application. I can't speak to what motivates Stereophile's review biases, but Magnepans latest top end speakers (30.1) just tied for speaker of the year in Absolute Sound.


Cat

 

Good question but I don't believe there is any magic in optimizing for high level vs low level signal inputs. It might be optimizing the cost of the unit by not offering the circuitry and connections to support each connection style but it shouldn't be that difficult.
The thing with low level inputs is that by not responding to the same signal the main speakers are responding to, the subwoofer response is already at a disadvantage and I don't know how you can optimize your way out of that condition, especially since the differences between preamplifier signal and amplifier signal varies from amplifier to amplifier.
The weird thing about my JL Audio subwoofer is that it offers both high and low level inputs- but recommends to use the low level from the amplifier preamp out. Still doesn't sound nearly as good as when the high level inputs are used.

 

I find this interesting. My question would be why do so many sub companies suggest using the LFE preout for their subs if it's not an optimal option? I think if one is using a sub for a 2.1 system high level inputs might be best as you have found. But many that are buying subs are using them in a multichannel system. I would also think that most sub manufactures are marketing their subs for multichannel systems. So that might be why many subs do not offer a full complement of high level inputs.

 

Again, strictly for the purposes of looking at this discussion from all logical points of view, would it not be possible for the proponent of utilizing line level sub inputs to say, since the ultimate goal is to preserve the integrity of the original (pre amp) musical source signal to the maximum extent possible, that there is an advantage to be realized by subjecting the subwoofer signal to only one pass through an amplifier stage rather than two?

 

Gents, heeding @head_unit 's advice and looking ahead to a possible integrated amp upgrade at some point in the future, I've been looking at the Peachtree Audio Nova 300 and the Parasound Halo 160.



Peachtree pros:
- Loads of power
- Specially designed iPhone USB input
- Less expensive

Cons:
- Only one preamp output suitable for line level sub use
- No bass management controls that I can discern (although if I stick with the Rythmik, it may have all the controls I need)

Link to back panel picture:
https://www.visionhifi.com.au/asset...Audio/Peachtree_Audio_Nova_300_ebony_rear.jpg



Parasound pros:
- More output options and controls than I'm fully able to comprehend
- Dedicated sub level controller right on front face of the unit

Cons:
- More expensive
- Less powerful (though perhaps not meaningfully so in my situation)

Link to back panel picture:
Parasound Halo 160 Watt Stereo Integrated Power Amplifier-Audio Advisor

 

Wow! You're really looking at expanding your budget! The Parasound Integrated ($2495.99) is an excellent choice but quite an expensive upgrade when compared to your speakers. I'd suggest checking out the Parasound P5 ($919.99) or 2100 ($549.99) preamps which are available as factory refreshed units from Audio Advisor. Then you'll of course need an amp and AA has the Parasound 2125v2 ($591.99) also available factory refreshed.

I have the 2100 in a second system and it's a great entry level preamp with provisons for connecting a sub. The P5 has more flexibility in regard to the sub with high and low pass settings where the 2100 only has low pass settings. I bought the 2100 from AA as a factory refreshed unit and it was in a sealed box from Parasound and looked brand new.

So doing the math on the above the P5 ($919.99), 2125v2 ($591.99) and Rythmik ($900?) sub package would be about $2412. If you went with the 2100 ($549.99) the total would be about $2042. Both of these packages would be less than the cost of the Parasound Integrated.

2100 - Parasound Classic 2100 Stereo Preamp-Audio Advisor
P5 - Parasound Halo P5 Stereo Preamplifier-Audio Advisor
2125v2 - Parasound Halo P5 Stereo Preamplifier-Audio Advisor

 

I'm sure there are some scenarios where this may be true, but I haven't had the experience.

I started my system with dual Polk SW111 subs. The sound I'm getting from my single SVS SB-2000 is night and day different. I have since upgraded my speakers (SVS Ultra Bookshelves) and my Receiver, but the sub was the icing on the cake.

Its the best $700 I have ever spent. Bar none.

 

Wow. Thanks, Bill. That’s a terrific value proposition. Definitely something to consider.

 

again, if the mains and sub are out of phase, the only result is a dip at the xo. when mains and sub are in phase, here cannot be a peak, ever. if you see a peak when you integrate your sub, its because your mains and sub are overlapping.

 

Just out of curiosity, is anyone familiar with the Paradigm Seismic 110? Seems as if it might have have the power - and more importantly the speed - to be suitable for music play, but most of the reviews I can find are from sites that are more HT oriented.

Paradigm® | Subwoofer | Seismic 110 | Overview

 

I'll be honest and ask why are you looking at a sub that lists for $1650? I thought you wanted to spend $1000 or under? You asked for recommendations for subs that are good with music at $1000 or less and there was not one suggestion for any subs from Paradigm. That should be an indication of whether the Paradigm is a good choice. No experience with Paradigm subs but the price of the Seismic 110 seems a bit steep for a 10" sub.

 

I just want to go back to the Rythmik LV12R again for a moment. I said earlier that I preferred my Outlaw Audio LFM-1 EX because it had more power that you can feel in your chest, or something to that effect. I want to 'reverse' that opinion here and now.

I revisited my sub setup and quickly determined that a 180° phase shift (ie, a reversal of phase) amplified and reinforced the bass by a significant amount. (Why I didn't try that before is a mystery even to me!) I rebalanced my 5.1 setup almost from scratch and went through some critical listening with both analog and digital music (including high-resolution stereo and multichannel audio), Blu-ray and DVD 5.1 movie soundtracks and YouTube low-frequency test tones. SATISFACTION ACHIEVED!! BTW, the scene in Finding Nemo where Darla taps on the glass tank always gets me. A subwoofer tester's delight!

 

The Elac would probably work just fine, especially with the options.

 

Hi, Bill. Sorry if it sounds like I’m asking you guys to hit a constantly moving target. I only mentioned this one because I saw the brand come up in a discussion focusing on the importance that speed plays in selecting a good sub for listening to rock music - and there just so happens to be a (supposedly) lightly used one available locally for a price that makes it comparable to some of the others that we’ve been discussing.

 

I briefly auditioned one in local dealer many years back. As I recall, it struggled in producing strong 30 hz tones, just like my JL Audio d110. That is why I am currently using twin 15" woofer sub.

 

Really? I figured that 110 would be spittin 30hz like sesame seeds. Interesting.
I did hear the Fathoms and they rearranged my colon:

 

No need to apologize. I just think that Paradigm even at close to $1k used is not going to give you the output that a 12" or 15" sub that's been recommended already. The other factor is service and accessibility to advice. Not sure if Paradigm has that as it is a fairly large company sold through dealers from what I recall.