[pankon]

Good evening!

I am pretty new in this group, so I apologize if I ask questions already answered in the past.

I have a pair of Falcon LS3/5a speakers, which I listen to near-field (1m from the listening position and several meters from the rear wall). They image like crazy and simply disappear from the room.

I love those little monitors, but due to their shoe-box size, they lack bottom end. I have been thinking of adding a subwoofer (I had a couple of models in mind), until I stumbled upon the GR research servo-controlled subs. Unfortunately, the LS3/5a BBC monitors (like my Falcons) are notorious for their mid-bass bump. Here are Stereophiles’s measurements  https://www.stereophile.com/content/falcon-acoustics-ls35a-loudspeaker-measurements  Some say that the mid-bass bump makes a subwoofer integration impossible. I am wondering whether a subwoofer with PEQ might do the trick. But hi-fi purists claim that a DSP will just kill the fine details in the bass. I am no expert, so I do not know what to believe.  I have in-room measurements of my speakers, performed by an expert, which that might be helpful...

Looking for quality and not quantity of bass, I would like to find a way to improve my Falcons and not to compromise their character (they "live" above 70Hz). So...

1) Sealed box or Open baffle subwoofer?  i.e. Kit 2 or kit 4?
2) One or two subs?
3) High-level input on line input?

Are the servo-controlled amps of GR research supported by a mobile app for setting the subwoofer parameters?

Thanks in advance for any replies.

Panos
Greece

[Tyson]

Dual servo subs, use them as stands for the speakers in a stereo pair.  It won't take up any more floor space than what you are already using for stands.

Just let the main speakers run full range and bring the subs in underneath - you'll be very surprised how well this works.  There is literally nothing in the world cleaner or more musical than stereo servo sub bass.  You are in for a treat!

Line level has always sounded best to me.  Make sure to get the A370 amp as it has much higher impedance than the Hypex amps (important if you ever want to use/try a tubed preamp).

[pankon]

Dual servo subs, use them as stands for the speakers in a stereo pair.  It won't take up any more floor space than what you are already using for stands.

Just let the main speakers run full range and bring the subs in underneath - you'll be very surprised how well this works.  There is literally nothing in the world cleaner or more musical than stereo servo sub bass.  You are in for a treat!

Line level has always sounded best to me.  Make sure to get the A370 amp as it has much higher impedance than the Hypex amps (important if you ever want to use/try a tubed preamp).

Thanks for your reply, Tyson. I've noted your suggestion about using the subs as stands

Make I kindly remind you that I have my LS3/5a in a nearfield position, i.e. 1m from the listening spot? Can the subs work that close?

Are you suggesting closed boxed or open baffle subs. I guess it's probably the latter, right? Can you please let me know which GR kit you are suggesting? Kit 2 or Kit 4?

Of course I am using a tube power amp, namely a Lab12 Suono https://www.lab12.gr/suono, a SET with KT150 tubes.

By the way, out of curiosity, have you ever tried LS3/5a with servo subs, or are you assuming that the combination should work well?

[Tyson]

Thanks for your reply, Tyson. I've noted your suggestion about using the subs as stands

Make I kindly remind you that I have my LS3/5a in a nearfield position, i.e. 1m from the listening spot? Can the subs work that close?

Are you suggesting closed boxed or open baffle subs. I guess it's probably the latter, right? Can you please let me know which GR kit you are suggesting? Kit 2 or Kit 4?

Of course I am using a tube power amp, namely a Lab12 Suono https://www.lab12.gr/suono, a SET with KT150 tubes.

By the way, out of curiosity, have you ever tried LS3/5a with servo subs, or are you assuming that the combination should work well?

Kit 4 is the way to go for sure. 

Nice amp you have there.  I run tube amps exclusively in my system now, in fact I seem to have an alarming # of different tube amps in my collection now, haha. 

I run planar magnetic speakers on top of my servo subs and I listen nearfield frequently - it's as close to seamless as you can get with a sub, IME.  Please, please, please avoid box subs if you don't have to use them.  OB servo is much better for music.  Since the subs will only be playing up to 70 or 80hz, and they are going to be placed close to your main speakers, then the blending is not a problem at all. 

[pankon]

Yes, I quite like the Lab12 Suono amp. And that particular version of the Suono has a 16Ohm output, which goes well with my 15Ohm LS3/5a speakers. And I understand that the sub amp is 16Ohm. I do not know whether that might make the high-level connection of the Suono and the sub amp easier than with a 'normal' 8 Ohm amp.

Does the sub amp come with its own box, does it have to be mounted on the sub frame, or something else?

How would I be able to set the parameters for the sub? By ear? Is there a more reliable way to do it?

Thanks a lot.

Panos

[Captainhemo]

No mobile app for sub amp control.

We offer some pretty simple   amp boxes here   
https://www.audiocircle.com/index.php?topic=139480.0

jay

[nickd]

How would I be able to set the parameters for the sub? By ear? Is there a more reliable way to do it?

I use an amp with sophisticated DSP correction and available high and low pass digital crossovers. Honestly, it’s a great tool kit, but your ear is needed if you want great sound. Measuring is helpful, but the servo subs are an easy matchup with proper placement and a bit of fine tuning to get a good blend.

Not having remote volume is the only real downside. With mastering being all over the place these days, it would be nice to be able to bump the volume from my listing chair.

That said. There is no substitute for speed and low distortion. The better your system and monitors, the more you need the servo subs. The servo in the feedback loop of the amplifier is game changing. There is no direct comparison that I have heard.

[pankon]

I am thinking of going ahead with a Kit 4 (open baffle, two drivers, A370PEQ), but only a single subwoofer for the beginning. I have to admit that since I have never heard an OB subwoofer, I am bit nervous to spend for subs more than my main speakers.

And since I live in Greece, it will take some time to get my hands on the kit with the drivers and the plate amp, so that I can then have the enclosure built. Then again, I am wondering whether a local carpenter can build it for me or whether I should order the enclosure from someone, who can send me flatfpacks.

Oh, and something else. Should I go for an H or W enclosure? Pros and cons for each one?

Any opinions are most welcome. Thank you.

[Captainhemo]

The H-frame is  a better  way to go  so long as you  don't  need to save a little height.

I did reply  to your  PM

jay

[pankon]

The LS3/5a are notorious about the difficulty to integrate with any subwoofer, probably because of two reasons:

a) the have a mid-bass bump (by design), probably to mask the lack of lower bass.
b) they are quite fast and subwoofers cannot usually keep up.

I wonder whether anyone in the forum has been able to integrate an OB sub with LS3/5a. Ron of New Record Day has tried OB subwoofers with Harbeth P3ESR, which are quite similar in size and character (not same, though) with the LS3/5a. He was quite happy with the results. https://youtu.be/llEq56KSys0?t=597

I am thinking of going for a single (mono) dual-woofer in an H cabinet. If I like it, I may add another one, in order to have stereo subs.

Any comments/advice are most welcome.

[Stercom]

Dual servo subs, use them as stands for the speakers in a stereo pair.  It won't take up any more floor space than what you are already using for stands.

Just let the main speakers run full range and bring the subs in underneath - you'll be very surprised how well this works.  There is literally nothing in the world cleaner or more musical than stereo servo sub bass.  You are in for a treat!

Line level has always sounded best to me.

Yep, after a lot of listening that's exactly how I use mine. Servos as stands, mains full range and line level input.

[pankon]

Yep, after a lot of listening that's exactly how I use mine. Servos as stands, mains full range and line level input.

Yes, I would not like to use a high pass filter with my main speakers. They will run full-range. I just have to be able to integrate the sub with the  mains. REL has been insisting on using their high level input (vs. low level/line input), but I cannot know the merit of that or whether it's just marketing hype.

I think I need to buy a calibrated mike, so that I can see what is measured at the listening position. I am not so confident about my ability to judge by listening.

[pankon]

By the way, my listening position can be seen in the attachments. In the drawing you can see the three candidate positions, when I was thinking of using a closed box sub (to convert meters to feet, please multiply by 3.28). Now I am thinking of using a single OB cabinet in the middle between the two loudspeakers, placed horizontally, instead of the coffee table.

[corndog71]

These servo subs are plenty fast enough to keep up.  I used a single sealed servo sub for years and it's a freakin monster.  But when I got the dual open baffle subs it was a revelation.  They don't load the room the same way as a sealed sub does.  The only down side is they need space to sound good.  You can't shove them into a corner or up against the wall. 

[pankon]

...The only down side is they need space to sound good.  You can't shove them into a corner or up against the wall.

Thanks for the feedback. Well, I think I have space, i.e. I am not intending to put the OB sub in a corner or against the wall. I am thinking of putting one OB sub horizontally on the floor between the two main speakers (in the photo I attached in a post above, it will replace the sub will be placed more or less where the coffee table is. I am curious about the result.

[corndog71]

Thanks for the feedback. Well, I think I have space, i.e. I am not intending to put the OB sub in a corner or against the wall. I am thinking of putting one OB sub horizontally on the floor between the two main speakers (in the photo I attached in a post above, it will replace the sub will be placed more or less where the coffee table is. I am curious about the result.

That's an interesting idea.  Danny has said laying them on the side like that would work.  Do it!

[pankon]

That's an interesting idea.  Danny has said laying them on the side like that would work.  Do it!

Yes, it was Danny's idea, not mine! I will just have to make sure that I decouple the cabinet from the wooden floor. Perhaps with spikes... Or maybe I should put a carpet

[mick wolfe]

Spikes would couple (not decouple) the subs to the floor. Probably not the approach you want, especially if it's a suspended floor. If your goal is to decouple, maybe look at the IsoAcoustics products for starters.

[pankon]

Spikes would couple (not decouple) the subs to the floor. Probably not the approach you want, especially if it's a suspended floor. If your goal is to decouple, maybe look at the IsoAcoustics products for starters.

Yes, I see where you are coming from. Let's get the OB sub built and then I can worry about the decoupling. But the IsoAcoustics idea is definitely worth checking out. I have herd of them but have no personal experience. Would you suggest a specific model, in case you have experience with them?

Thanks!

[mick wolfe]

My only experience is with the Orea line designed to be placed under components. The IsoAcoustics line for speaker isolation can get pricey with the exception of the "pucks" they offer for pro/studio use. Auralex also offers a reasonably priced "footer" to be placed under speakers as well. Those are two that come to mind although there are probably dozens of other possibilities. Now that I think of it, DiversiTech ( SupplyHouse.com) offers isolation pads for industrial equipment that seem to work well under components/speakers as well. Very inexpensive option.