About to try integrating subs...

[MadFloyd]

I’m experimenting with tube amps and am getting great midrange and soundstage, but lacking in deep bass.

Rather than push my speakers back towards the wall to reinforce the low frequencies (currently about 3.5’ out) I’m thinking of trying subs. I have a pair of JL Audio F113’s that I can try, but these don’t have speaker level inputs, so I *think* the best way is to run interconnects directly to their inputs using the second set of outputs on my preamp.

I’m planning to crossover low, but of course I’ll experiment.

Any tips?

 

[DonH50]

I agree with using the pre outs to the crossover.

While you could try passive, dbx makes a decent fairly inexpensive crossover (try Sweetwater sound). Bryston makes a great but expensive crossover that allows more flexibility. Marchand makes very good fixed crossovers (active or passive; I prefer active, honestly) once you know the frequency (unless you have it already figured out). I decided to start with dbx but have not gotten aorund to upgrading a year or two later (thanks Mark, still using it!) It is nice to have variable frequency when starting out.

I like to start with the crossover about an octave over the mains low end spec, though of course if they are spec'd fairly high I would not follow that guidance (I would not set over 100 Hz as IME everyone can localize the sub by that frequency). For reference, my Maggies crossover about 1/2-octave above their -3 dB point (35 Hz low-end spec, crossed over at 50 Hz, may raise to 60 Hz).

I have used a tube amp for mid/highs and hybrid (tube/SS) or SS bass amp in an actively bi-amped system with great success. Perhaps another option. For me, the hybrid blended much better, but my Maggies have a low-order crossover so I needed close matching of bass and treble amps. YMMV.

HTH - Don

 

[MadFloyd]

Thanks for the rely, Don.

I was planning to use the crossovers in the subs. What would be the reason to use an outboard one instead? Reducing delay?

I'm not planning to use a crossover on the signal going to the main speakers as that would degrade the quality way too much for my liking (I've owned the Bryston - it crushes the sound imo, also used to own a Rives Parc for bass EQ and that squeezed the life out of the signal as well, putting me off this sort of thing).

 

[RBFC]

Once you've set the crossover frequency for the subs, play a test tone at that frequency through one channel only. Disconnect the other channel, and invert the polarity of the main speaker's leads on the channel you've left on. This will put that speaker at 180 degrees out of phase with the corresponding sub. Adjust the sub's phase control (or distance from the listening position) until you hear the least sound, meaning that the arrival time of the sub and main speaker are closely matched. Repeat the process for the other channel. Note: this will work even if you don't have the volume of the sub and main speaker matched, but best results will be if you can equalize levels first.

Good luck,

Lee

 

[edorr]

I’m experimenting with tube amps and am getting great midrange and soundstage, but lacking in deep bass.

Rather than push my speakers back towards the wall to reinforce the low frequencies (currently about 3.5’ out) I’m thinking of trying subs. I have a pair of JL Audio F113’s that I can try, but these don’t have speaker level inputs, so I *think* the best way is to run interconnects directly to their inputs using the second set of outputs on my preamp.

I’m planning to crossover low, but of course I’ll experiment.

Any tips?

I used 2 x JL113 with my avalons. I would suggest inserting a bass EQ unit in the sub signal path (I used the SVS, there are others). For a 2.2 setup you want a discrete stereo bass EQ unit. Since you'll be running the mains at full range (presumably), you need to cross over very low.

 

[Steve Williams]

I use 2 Gotham subs with my speakers playing full range. I cross the subs at 43 hz so I am supplementing the bottom end with the subs.

I use the second main out from my preamp and run these left and right through a tube buffer and then to my subs. Tube amps and the Gotham subs have a huge input impedance misbalance. Hence the tube buffer

 

[MadFloyd]

I use 2 Gotham subs with my speakers playing full range. I cross the subs at 43 hz so I am supplementing the bottom end with the subs.

I use the second main out from my preamp and run these left and right through a tube buffer and then to my subs. Tube amps and the Gotham subs have a huge input impedance misbalance. Hence the tube buffer

Do you mean your tube preamp and the subs have a impedeance misbalance?

 

[Steve Williams]

No I mean my Lamm ML3 has a huge impedance misbalance between it and the Gotham subs. IIRC the Lamm is 41 kohms and the Gotham is 10,000 kohms. I would have to look that up however for exact numbers

 

[MadFloyd]

No I mean my Lamm ML3 has a huge impedance misbalance between it and the Gotham subs. IIRC the Lamm is 41 kohms and the Gotham is 10,000 kohms. I would have to look that up however for exact numbers

I'm confused. If you're running direct from the preamp to the ML3's and in parallel direct from the preamp to the Gotham subs, how does the impedance of your ML3's have any bearing on the relationship between your preamp and the Gothams?

 

[Steve Williams]

Because my Lamm preamp is driving two loads. One to the Gotham subs and another to the ML3. There is a huge impedance mismatch with one being 41Kohms and the other 10,000 Kohms

 

[DonH50]

I use an external crossover because I usually roll off the mains as well; they usually have much lower distortion and greater dynamic range if you offload the bottom end. If your preamp already rolls them off (as do many AVRs) you are covered.

Another way to adjust the phase is to leave everything one, play a tone at the crossover frequency, and adjust the delay/phase/whatever for maximum sound at the listening spot. The null test is easier to do by ear but takes more work; the max test works OK by ear but an SPL meter helps. Best is to measure the impulse or step response and align wavefronts, natch...

Steve, I do not follow your impedance mismatch issue. if the preamp has a low output impednace, then the load shouldn't matter too much. The two amp inputs, if that's what you mean, are in parallel so the net load resistance is lower than the lowest value (Rtotal = R1 * R2 / (R1 + R2) ). The input voltage applied to both amps should still be the same if they come from the same source (e.g. a y cable or parallel preamp outputs).

 

[RBFC]

If you're using two subs in mono configuration, you can just flip one of them to 180 phase and move them to achieve the lowest sound level when playing an LFE test tone. In any case noted by Don or me, an SPL meter is highly advised.

Lee

 

[Steve Williams]

I use an external crossover because I usually roll off the mains as well; they usually have much lower distortion and greater dynamic range if you offload the bottom end. If your preamp already rolls them off (as do many AVRs) you are covered.

Another way to adjust the phase is to leave everything one, play a tone at the crossover frequency, and adjust the delay/phase/whatever for maximum sound at the listening spot. The null test is easier to do by ear but takes more work; the max test works OK by ear but an SPL meter helps. Best is to measure the impulse or step response and align wavefronts, natch...

Steve, I do not follow your impedance mismatch issue. if the preamp has a low output impednace, then the load shouldn't matter too much. The two amp inputs, if that's what you mean, are in parallel so the net load resistance is lower than the lowest value (Rtotal = R1 * R2 / (R1 + R2) ). The input voltage applied to both amps should still be the same if they come from the same source (e.g. a y cable or parallel preamp outputs).

Thank you Don. That's what I meant. The two loads are in parallel. I was told by JL Audio that a tube buffer is not necessary but based on your above Formula, that's why I use one

 

[DonH50]

Got it. 10k in parallel with 41k = 8.039k ohms, a pretty low load for most tube preamp outputs. I do not recall how low my old SP3a1 was rated, but do recall it did not like my 10k SS amp input (too low). It was much happier with 50k, and did great with my D79 (100k).

 

[Steve Williams]

I have never regretted using the tube buffer in conjunction with my setup based on the above

 

[theguesswho]

Hi MFloyd, Your first problem is that all tube amps have rolled off highs and have bloated bass. The second thing I see is a cable missmatch with your speakers, have you tried other cables?

I don't believe that a crossover will be good as it can only add more electronic distortion and as you said " it crushes the sound imo, also used to own a Rives Parc for bass EQ and that squeezed the life out of the signal as well, putting me off this sort of thing). "
I totally agree with you on this. This is what I hear whenever I have added "outboard processors". I have never heard a system with EQ sound good and certainly never great! That can only be achieved with minimal electronic artifacts. Every time you add an additional piece of equipment, especially something like an equalizer or any other distortion adding device your sound suffers. It will squash dynamics, add distortion and noise; creating a sonic veil that cannnot be removed untill the offending equipment is removed from the chain. You need to maintain the purity and essence of your system.

As far as subs and crossovers go, if you are going to try a sub for MUSIC cross over below 40hz at most, the 80hz is ok for big boom boom home theater but not music! I don't recommend it.

Your Sashas go down to "Frequency Response: +/- 3 dB 20 Hz - 22 kHz Room Avg. Response" according to the Wilson site, so how much lower do you want to go?

Wendell
PHP143

 

[DonH50]

Uh, you can get passive crossovers, and a look at the distortion curve as frequency goes down and power goes up can be very humbling for virtually any speaker.

 

[MadFloyd]

Hi MFloyd, Your first problem is that all tube amps have rolled off highs and have bloated bass. The second thing I see is a cable missmatch with your speakers, have you tried other cables?

I don't believe that a crossover will be good as it can only add more electronic distortion and as you said " it crushes the sound imo, also used to own a Rives Parc for bass EQ and that squeezed the life out of the signal as well, putting me off this sort of thing). "
I totally agree with you on this. This is what I hear whenever I have added "outboard processors". I have never heard a system with EQ sound good and certainly never great! That can only be achieved with minimal electronic artifacts. Every time you add an additional piece of equipment, especially something like an equalizer or any other distortion adding device your sound suffers. It will squash dynamics, add distortion and noise; creating a sonic veil that cannnot be removed untill the offending equipment is removed from the chain. You need to maintain the purity and essence of your system.

As far as subs and crossovers go, if you are going to try a sub for MUSIC cross over below 40hz at most, the 80hz is ok for big boom boom home theater but not music! I don't recommend it.

Your Sashas go down to "Frequency Response: +/- 3 dB 20 Hz - 22 kHz Room Avg. Response" according to the Wilson site, so how much lower do you want to go?

Wendell
PHP143

Hi Wendell,

Were you referring to my PAD cables? Why do you think they are a mismatch? (not arguing, I just want to learn)

I'm actually using Transparent Ref XL cables at the moment (auditioning them due to their reputed synergy with Wilson).

Ian

 

[theguesswho]

Hi Ian, this is the 3rd time trying to post a reply, dont know why the first two posts ...didn't post.

So I will make this short and sweet.

I have never heard Wilson Sophia or any Wilson speaker be bass shy. Many audiophiles claim Wilson to have, if anything, too much bass! The specs say they go down to 20 to 22hz, which is what I hear when I have heard them with appropriatly matched equipment.

Your Lammm and Doshi pre are reference quality and certainly not rolled off. The Dynavector XV1s phono cartridge is one of my favorites...

The only thing that leaves us with is cables. I do like the PADs but I would think the Transparent to be the better more extended cable in the lower octaves. Though this is still system dependant and your preference as to what you like in the sound of you cables. My thought is that you have great equipment and no reason not to have low bass except for cableing problems. Dont forget it could be speaker cable or the power cable too!

As you know, anytime you add another outboard processor (what can be worse than an equalizer? Have you ever heard one sound good?) you destroy the purity and essence of the system. Adding more electronics can only add more distortion, noise and electronic artifacts. Then factor in another two sets of cables and it is a recipe for disaster! But you know that already.

Wendell

 

[JackD201]

Come to think of it, I recommend middle range Purist to folks with issues with brightness. I use them myself (Venustus) in my HT where my Marantz Pre/Pro and VK-6200 are an edgy combination. My dad likes a midrange-y sound and he uses Museas.