[pmorcos]

I apologize in advance as I never learned how to keep things brief. I’ll also apologize for thinking about adding a sub to my stereo pair of X.3’s.  I recently moved my X.3’s into a new house, and they are in a great room… Literally. The room is over 100 feet long and a little over 20 feet wide with a lot of windows. It’s not a simple rectangle but for the most part it’s just a giant room and right now I’m using a node to stream tidal hi-fi and Radio Paradise MQA files into a parasound halo P6 preamp and ultimately a parasound a 23+ amp. Perhaps surprisingly the speakers sound great in this room (after moving them a lot and out into the room)… everything sounds live, however sometimes the mid and mid bass actually sound too bright. I do like to listen to music fairly loud and even with the bass dial right at 12 o’clock on the X threes I have had some clipping and it seems as though the 15 inch drivers are being taxed. I am planning on trying two things at once… one is for sure…
I am going to swap out my parasound preamp for the streaming dirac live-enabled NAD C658. I was going to use the NAD and dirac live (bass management) to send roughly 35 to 40hz and below to a powered sub and 35-40 hz+ to the X-3s.  I am interested in the Audiodyne 18s (sub 6) which has only 500 watts and dual 9” drivers.  I feel like it may provide that 20-40hz that the x-3s seem to struggle with. Is it enough? Am I crazy? Don’t answer that.  Also I would like to wish Clayton get well soon.

[richidoo]

Welcome to AudioCircle!

Two 9s is the same as one 9 except 3dB louder. A real 18" cone is a whole different world musically, bass extension, detail, efficiency, dynamic range. The 9" is too small for your room, imo. It's a  myth that smaller woofers add together to work as well as a larger woofer. Woofer size is proportional to room volume. For the size of your room I would recommend getting a very large subwoofer or two.  SVS SB-16Ultra is a nice sub, good value for what it offers.

If you only care about the bass in the listening position 8-10 feet from the speakers and you aren't a bass head or into dancing than a single 15 would probably be enough to hear the low bass clearly with decent transient response at 30Hz. But it won't scare you when the music calls for it. 

It's not about peak SPL. It's about how clear does it sound at LF. Can you still hear satisfying bass at lower volumes? This might be important to you with a large great room if you listen after others go to bed. You want to play music softly but still hear the bass clearly. Small woofers don't do that.

[RonN5]

A couple things….

For music, you will find if you have a sub with a crossover control that there isn’t much sound/output below 50hz… so a separate sub might not help much unless you cross it in the 50/60hz range.

That is a huge room and there is no replacement for displacement…. 15” minimum… or maybe two 15”ers to smooth things out.

[pmorcos]

I really like both of your opinions/thoughts. If I were to choose one 15inch sub…. What choices besides svs? I am not inclined to haul around 100lb subs. Options?

[richidoo]

Yeah, unfortunately, good subs are heavy, because the strong cabinet and powerful driver are the causes of the good performance.
The weight is actually beneficial to the performance.
You need a really good sub to keep up with the clarity and speed of Spatial speakers.

Some other mfgs of high performance subs: Legacy Audio, Paradigm, REL, JL Audio.
GR-Research makes a good DIY kit.

Hopefully you won't have to "haul it around" very often.

[RonN5]

Here you go… PSA makes good sounding sealed subs. Make an offer for either one… or both.

https://www.usaudiomart.com/details/649911006-power-sound-audio-xs15-subwoofer-pair/

[pmorcos]

What do you all think of the paradigm defiance x15? I have some experience with paradigm but not their subs.

[Bingenito]

Like Ron said crossover higher and in a large room you need real displacement to extend from 60hz to the bottom octave. 2-9" is a waste of time regardless of what any marketing tells you. Physics overrules dealer, reviewer and marketing nonsense.

I would look at large sealed designs. My Arendal 1723 2s in my theater room is much better than most of your audiophile brand subs. Ultra clean, real extension into about 14hz in room and integrates perfect with mains. It is large but if you need SPL 16-32hz it needs to be. Just facts regardless of what anyone tries to tell you.

[richidoo]

What do you all think of the paradigm defiance x15? I have some experience with paradigm but not their subs.

Too heavy 

Paradigm is awesome! Defiance 15 is ported, and for audiophile music playback you definitely want a sealed box for better transient response, which means more detail, more natural musical sound. Ported would sound too punchy compared to Spatial, and the port adds a lot of delay to the bass, which would blur the low end of Spatial. When integrating sub with main speakers the success depends on 2 things: correct volume matching, and phase coherence (sub position, low pass filter slope, delay setting, and bass alignment and group delay of the main speakers.) A ported sub makes integration more difficult or impossible. This is why sealed is essential for music/hifi subs. 

[pmorcos]

Again super helpful…
The Arendal 1723 2S looks like a perfect fit and cross it up to 80 or even 100hz.
At $2400 this is going to be an expensive experiment.
 

[Bingenito]

$2400 is a deal for the performance. Look at my former threads… had a pair of Rel Carbon Special sold them after trying them in my HT room. Still have the Arendal… real sub bass ext that is clean, tight, and blended perfectly with DSP.

[Desertpilot]

I have X3s and two SVS SB13Ultra subs.  My system is also located in our "great" room.  It's about 40 feet wide and 30 feet long with vaulted ceilings 11 to 14 feet.  Lots of space.  I set my crossover at 40 Hz although the X3s are great down to 30 Hz.  My system is also used for home theater.  I wanted my subs to handle explosions and car crashes.  I play classical music.  Bass notes on a piano and double bass instruments will get down low.  I'm am advocate of duals subs.  Larger drivers for your size room would be preferable.

Marcus

[pmorcos]

I am all in for the single arendal sub. I think it will be a perfect match and between the onboard dsp and the dirac live I feel confident I can restore a nice round sound missing after I moved the X-3s. I also love the idea of opposing bass drivers and also that they will not be pointing at the listening position. I will likely wait until right after the holidays but I will post my thoughts. I am a little concerned about the colors… the X-3s are the light wood and I am thinking matte or gloss white for the Arendal to “blend in with the wall”. 

[Bingenito]

My 1723 2S is matte white. Very clean look, modern and simple. It matches anything. Black is nice but a dust magnet. I will warn you it isn't a small sub but if you want real extension at SPLs needed for a room that size I would not use anything smaller.

What I love about the 1723 sub is that for some music you have no idea that it is there and then tracks that have real bass extension and dynamics you just feel it, like oh yeah there is the bottom octave. Unlike most subs they are so clean that they never call attention to the subwoofer.

I had an easier time integrating the large 1723 2S then 2 small SVS and certainly better than REL.

[pmorcos]

My 1723 2S is matte white. Very clean look, modern and simple. It matches anything. Black is nice but a dust magnet.

What I love about the 1723 sub is that for some music you have no idea that it is there and then tracks that have real bass extension and dynamics you just feel it, like oh yeah there is the bottom octave. Unlike most subs they are so clean that they never call attention to the subwoofer.

I had an easier time integrating the large 1723 2S then 2 small SVS and certainly better than REL.

I am not worried about the size since nobody is walking behind the speakers and I may actually be able to get away with moving the X-3s closer to the wall with this sub.
Looking forward to hearing the difference.

[dlynch34]

another thing to consider would be looking into GR Research.  I have actually considered going to an OB sub configuration with my X3 to match.. Presently I have a dual sealed configuration at my front stage which is decent.  https://gr-research.com/sub-series/

[pmorcos]

I like the idea and I have built my own speakers before but I am not sure I want to do this as it will be hard to sell if I don’t love it.  Do you know of any good reviews of the double?

[pmorcos]

Presently I have a dual sealed configuration at my front stage which is decent.

What do you have and where did you place the sub in relation to the x-3s?

[dlynch34]

I built 2 sealed subs each one sits next to one of the x3 speakers. 

[pmorcos]

After much deliberation, I am down to the Arendal 1723 S2 and the PSA S3012. Very different beasts… one overly manufactured new breed vs. old school power. Leaning Arendal.