preamplifier after preamplifier?

If your active, and I assume powered, subs have their own cross-over and gain control, why not simply connect them to your amp via the sub’s high-level speaker terminals (if they have them), not your pre? (share the binding posts with your mains). If powered subs, this is very safe for the amp as you are simply sending the shared signal to the subs, not powering them. In this way you can simply adjust the subs to the mains in terms of integration.

I do this, and my subs are in ’stereo’, albeit, no, I do not expect to hear them in stereo, it’s just easier that way in my set-up. They only activate when necessary per my crossover and gain setting, basically supplementing the mains.

Now, if you want to control the subs gain for each selection of music, perhaps your idea works better, or, perhaps you have no high-level terminals on your subs. For me, it’s adjust/integrate them and done.

The active subs should have a gain/volume knob on the sub's amplifier control panel. What purpose would the additional pre-amp provide, that the volume control knob on the sub does not already provide?

I agree with @bkeske 

This is by far the best method to connect subwoofers. The last thing you need is an additional preamp in the chain.

Oz

I know what he’s talking about the subs don’t increase enough to match the mains when you turn it up. Then when you match the mains at a higher volume and then turn it down again the subs is to loud.

That’s the problem with higher sensitivity speakers and most subs.. Most subs sold use high excursion speakers, but low sensitivity. 83-85% is not uncommon. One of the main reasons I build my own or make darn sure they match pretty close.

GR servos are 90+ so are all the subs I use. HO44 10" Daytons 90+ @ 8 ohms. Dayton 225-4 is a 8" mid bass driver, I use in Bass columns are 91%.

My mains are 92-3% planars/ribbons..

No matter what I do the bass is correct. Very low volume or very high volume, 300hz and down matches perfect with 300hz and up. Not always easy to do, without getting up and changing the gain by hand on the subs.

The OP likes two remotes.. LOL

Another option is use a preamp with a separate sub out. Mcintosh and Krell both had that option on their HT/Stereo series. The Subs had a separate +12db gain from the mains and Mcintosh had tone control to boot..

I think a Parasound Zpre3 has separate bass and sub volume control. I have one. :-) Just been a while.

Regards

Correct me if I’m wrong, but I would say the OP needs to clarify what he means by ’active’ subwoofers. Does that mean ’powered’ with their own amps inside, or actually simply ’active’ like any other speaker, or, non-passive.

If they are actually ’powered’. I don’t think it would matter how you hooked them up, as the subs internal amp will take the incoming signal and power that sub. Thus, I cannot see how you could change the volume with a preamp or integrated without a dedicated sub out/LFE volume control option.

If they are truly ’active’ subs, then yea, I guess you should/could be able to control their volume/gain separately with a preamp or integrated depending on out options.

@oldhvymec I just recently decommissioned my ZPre3, as I just ’stepped up’ in the world of preamps. Great little pre though, served me wonderfully. It, the Zpre3, has a single sub out, and also a mono out. I think both are fixed. And, no seperate sub volume control on that pre. I think you have to get up to the New 200 series to get that. It also has both R/L fixed and variable control outs.

Preamp? Overkill.

Just insert one of these.to the sub feed.

Then you have RC at the listening position.

I do.

All else is blather including 2 remotes, har har funny.

I've got TV, cable box, BluRay, AVR, HiFi pre amp, DAC, SHD Studio selector, subwoofer level and headphone amp on ONE $8 programmable remote.  Plus a Windows PC remote I don't use anymore is on it.

He is saying his subs are active or powered. A passive sub usually has an onboard XO, but there is Debra, Swarm designs that run 1-4 subs per amp and the amp has the low pass filters and settings. Dayton 1000s are very popular, run one or two.

I use a DCX2496, just for the convenience and ease to add a passive subs or bass column (up to 6 and the controller is daisy chainable 128 nodes). Heck I can even add a rumble filter for TT use or use it as a band pass for my Bass columns. 100-300hz and it has zero effect on GRs OB servo sub DBA I use from 100hz and down.

MY point is simple if all your drivers are matched pretty close including the subs, turning the volume up or down is usually ok with most systems. When you have KHorns. or Corner horns, or La Scala, you'll understand what the OP is probably talking about IF you had most subs.

The speaker efficiency don't jive, can you dig it? 100%+ efficient main speakers with 85% subs don't work. For ME!. They might for you. :-) That would drive me completely bonkers, my wife would go nuttier than she already is, bouncing up and down to match subs. AND she would, trust me.

Maybe I'm to picky. :-)

Regards

@flemmingss - Sure, what you have diagrammed will work. It will give you the independent control of relative level that you want.

You don't need another preamp just a passive volume knob. Here's one: Amazon.com: Nobsound High Precision Passive Preamp Volume Controller VOL Control HiFi Preamplifier ALPS (RCA&HiFi Version, Black) : Electronics

You could bet a Parasound P7 which has this built in. So does the 5 and 6. 

*L*  I was going to hawk the 2496 active xover, but the old heavy was light on his feat.... *s*  Won't cost like another pre, either....

@fuzztone  and lighter on the entry fee, too....and I'm amazed at the 'one remote to bind us' approach.

( *note to self*  Do Not 'Thumb Fight' with this man. )

You just need a postamplifier and you are all dome

The one thing I really like with a DCX2496 is I can run Behringer amps with it and they are made for each other. I use up to 3 NU12,000. All the drivers are direct coupled, no crossovers between the power amps and subs.

About 2000 watts @ 8 ohms 4000 @ 4 ohms. I’ve pushed 1 ohm for a while, 2 ohms no problem at all. They have very good cone control, the best I’ve ever seen actually, other than servo.. At 8 ohms. Clear deep solid bass. Those 12K will pump it out. They were about 500.00 each. They are close to 800.00 or more now. The secret is out. :-) I can’t break one. I been trying for over 6 years now..

Regards

Using my Marchand crossover and passive subs, I set the gain on the crossover @ 10am and the mains at 3pm.  Quite a difference.  And I have very efficient speakers. May not help here but it is possible to use high efficiency speakers. 

OP,

In both of your diagrams above you are still putting all of the bass freqs into your main speakers.  Unless you have dual binding posts on your speakers and even then you would be taking out the woofers in the mains entirely.

The passive volume seems a nice work-a-round but see paragraph above.

I have to agree with @daledeee1 that a two-way Marchand electronic cross-over
is the way to go.  They are all custom made in the respect that you chose the 
slope and the cross-over freq.  That way you're not beating up your amp with all
the low bass that the subs are going to play anyway.

If there's more to the story please let us know.

I have no affiliation with Marchand. Just take a peek at their offerings.

www.marchandelec.com

Regards,
barts

I forgot to mention, or ask a question.  The first preamp has gain.  Feeding that to the second preamp, is that too much gain in the end?

Two preamps, no, simply no.

@fiesta75 

+1

I use the high level inputs on my Rel S5 Sho subs.  I have them connected directly to my amp outputs.  Works great.  I believe it is actually sonically better.  

on my SVS sub you can run speaker wire from the power amp speaker output to the sub and volume will be controlled by the preamp volume.  thety call it high level input on the sub.  

Not possible because the first preamp output will be too high like firca power amp and not for a preamp.    The second preamp will need a low output like from a source example Phonostage ,CD PLAYER or DAC . unless the first preamp has a source direct out.  

Correction to above entry.   Firca should read for a   Power amp

Do you have a tape out on preamp 1? If so use that to drive preamp 2. Then use preamp 2 for volume control for subs. There are a few postings about this type of hookup.

This is the hookup I use for controlling my passive suds. Tape out to preamp 2, then to my external crossover, then to DSP for subs only. then to dedicate power amp for subs.

Hi Guys,

Signal purity to be highest goal here.

any preamp externally on top of another or dsp will work against it.

Solution for it in case of using digital front end with both volume control and a DAC, such as a CD player, connect player’s RCA outputs to subs directly and player’s XLR to your preamp. Or use Y splitter at player’s RCA Outputs.

so any kind of combination with volumes of your speakers and your subs is possible.

I do this for years now with my Nagra system. Very exiting every session…

Enjoy the music.

2nd advantage of this solution, you always need to deliver signal to subs as early as possible since sub drivers are not fast in reaction. So your speakers receive the signal little later than subs. Result is matching phase of both drivers (normal speakers and subs) if sub signal arrives at your ears too early use subs’s delay or phase knobs to adjust.

works flawlessly.

any solution with dsp or 2nd preamp cannot beat above.

Enjou the music…

Didn't Elizabeth have three preamps daisy-chained together at one point?

I wrestled with this for years. Bought a dbx drive rack 360 and love it. Very versatile. Check it out. Control all speaker volumes, delay, parametric/graphic eq-the list goes on and on. 

We suggest keeping the system as simple as possible, with one preamp, our choice is the miniDSP SHD, it would integrate like this:

Here is the functional block diagram,  this allows for full control over all crossover slopes and frequencies, channel levels and delays.  Most importantly, Dirac Live room correction.

@deer_creek_audio 

Thank you for posting this suggestion. This is a really intriguing solution. I have been looking for something that will provide better subwoofer integration and possibly room correction. The McIntosh MEN 200 does something similar, but it is significantly more expensive and it doesn't provide this level of adjustment. 

The miniDSP SHD works well, I can add from my own experience. So does the Anthem STR Preamp, which has similar functions and a nicer interface, but costs twice as much, lacks a streaming network input, and is currently very difficult to find.

Other candidates might be some units by Lyngdorf and the DSPeaker X4. I have not heard the last two. In general, as @deer_creek_audio pointed out, a DAC-preamp with DSP including crossovers for subs is a great way to configure a system with subs. It can give the fine control of LF response that is impossible to get in most rooms any other way, so excellent sub integration and flat response in the low frequencies.

P.S. Some of the new NAD gear is similar in block diagram, too, and might be worth considering if you want to go in this direction.