Which sub should I go with? Kef or Boston

nluck83

Novice Member
HI all,
I am revisiting the world of home AV as I now have a media room in my new home. I have ceiling Sonance speakers powered by a Denon Denon AVR-X3500H with a Boston PV500 sub. I've has this sub for 15+ years. Its served me well and its never been abused. It sounds pretty darn good to be honest but IMO could be tighter base. After googling it this sub looks to be closing in on 20 years of age. Here are the spec's on it: Boston PV500

High level on the Boston sub:

Product highlights:​

  • bass-reflex design
  • 100-watt RMS amplifier
  • 10" down-firing driver
  • frequency response 38-180 Hz (±3dB)
  • continuously variable 75-150 Hz low-pass crossover
  • line-level input and LFE input
  • speaker-level inputs with binding post connectors
  • phase control
  • front-mounted volume control
  • auto on/off
  • 12-1/4"W x 13-5/16"H x 17-1/16"D
  • warranty: 1 year
  • Our 60-day money-back guarantee
  • MFR # PV500
Now I've come into possession of a Kef Kube8B subwoofer that is pretty much brand new. I swapped it out with my Boston tonight, played some music and it seems to be nice. I haven't compared them yet though with watching a movie or anything. I was going to sell this Kef but since I've owned this Boston subwoofer for so long I was thinking I should keep this Kef and get what I can for the Boston.

High Level spec of the Kef:

Product highlights:​

  • frequency response: 34-140 Hz (-6 dB)
  • built-in Class D amplifier delivers 300 watts RMS of continuous power
  • custom-designed 8" woofer
  • acoustic suspension (sealed) cabinet design
  • iBX (Intelligent Bass Extension) digital signal processing provides deep, dynamic bass at any listening level
  • 3 placement presets (free standing, in-cabinet, or corner) let you choose your sub's location for optimal bass performance
  • variable low-pass crossover (40-140 Hz)
  • phase control switch (0-180°)
  • line-level/LFE RCA inputs
  • main power on/off switch plus auto standby/on mode
  • detachable power cord
  • 11-1/2"W x 11-1/2"H x 12-1/4"D
  • weight: 25 lbs.
  • warranty: 5 years woofer, 2 years amplifier
  • Our 60-day money-back guarantee
  • MFR # KUBE8B

What would everyone do here based off of these two subs? Should I keep the Boston or ditch it and go with the Kef? I am so out of the tech/loop on subwoofers I figured I'd come back here since I used to frequent these forums a lot as a visitor. If the answer is Kef is there a best practice to follow when pairing it with a Denon AVR-X3500H? The spec's on both SEEM to be similar but since the Kef is so much newer not sure if its worth switching to or not yet. Really appreciate the help here!

Nick
 
Last edited by a moderator:

Gasp3621

Distinguished Member
I would trust your ears. Does the Kef sound "tighter" as you said the Boston could do that bit more? Place it in same spot assuming it´s optimal in first place. For a small sealed sub when you have effective sub eq in hand i would place it in front corner (furthest from any opening). Run 3mic position Audussey turn the gain so high you get 77-78db reading with the on-screen Audussey setup. That may be end of green start of red zone, don´t worry about the warning "too high" it won´t be issue. Subwoofer level comes back about -6db after setup if you check from the menu. Then you can tweak this figure reducing it lower by 3-6db typically if you want more oomph, don´t touch the knobs behind the sub anymore.

Behind the Kef set the knobs before running Audussey:

Connect cable to LFE.
Phase switch 0
The EQ switch to "wall" although you can play with these later, in-room gives biggest boost for low end, but you lose the boost if you set this before Audussey so try it after Audussey.
Crossover knob to LFE

After finishing the Audussey run check that you have subwoofer mode as LFE (no lfe+main) and LPF for LFE 120hz. Speaker size all Small and bump up speaker crossovers if they are set below 80hz.
 

AmericanAudio

Well-known Member
AVForums Sponsor
Traditionally, speaker manufacturers dont make brilliant subs and vice-versa.

Depending on budget, performance and the level of control you want have a look at these (and others)

SVS
Monolith by Monoprice
JTR (as you are USA Based)

Plenty of other Sub specialists in the USA too.
 

nluck83

Novice Member
I would trust your ears. Does the Kef sound "tighter" as you said the Boston could do that bit more? Place it in same spot assuming it´s optimal in first place. For a small sealed sub when you have effective sub eq in hand i would place it in front corner (furthest from any opening). Run 3mic position Audussey turn the gain so high you get 77-78db reading with the on-screen Audussey setup. That may be end of green start of red zone, don´t worry about the warning "too high" it won´t be issue. Subwoofer level comes back about -6db after setup if you check from the menu. Then you can tweak this figure reducing it lower by 3-6db typically if you want more oomph, don´t touch the knobs behind the sub anymore.

Behind the Kef set the knobs before running Audussey:

Connect cable to LFE.
Phase switch 0
The EQ switch to "wall" although you can play with these later, in-room gives biggest boost for low end, but you lose the boost if you set this before Audussey so try it after Audussey.
Crossover knob to LFE

After finishing the Audussey run check that you have subwoofer mode as LFE (no lfe+main) and LPF for LFE 120hz. Speaker size all Small and bump up speaker crossovers if they are set below 80hz.
Thanks - I will play with this today!
 

nluck83

Novice Member
Traditionally, speaker manufacturers dont make brilliant subs and vice-versa.

Depending on budget, performance and the level of control you want have a look at these (and others)

SVS
Monolith by Monoprice
JTR (as you are USA Based)

Plenty of other Sub specialists in the USA too.
Thanks for the reply. So Kef isnt a "good" sub brand? The price of this one I have wasn't cheap and looks to be similarly priced to SVS and Monolith subs. Would I be smart to sell both subs and invet it into one of the brands you mentioned? I would be OK with the 600-800 price point. Or are you thinking higher end line of these mentioned brands?
 

josefK666

Active Member
Whilst I agree with the general notion that often the subs that speaker manufacturers come up with don't match those of sub specialists nevertheless KEF don't make junk. I have a KEF 10b and it's perfectly decent though I was given a very good offer for it!

One option you might want to think about is selling the Boston and actually getting a second KEF 8b!! You'll find all sorts of information about the benefits of dual subs online but the main one is to assist in smoothing out the inevitable peaks and dips you will get with the bass frequencies with a single sub - duals can definitely improve that - and so then improve the bass response throughout your media room. You talked about wanting 'tighter' bass - the KEFs are sealed subs and often this type are considered to have slightly tighter more controlled bass too.

At the end of the day though if you've got a medium/large room and you want a sub to crank it up for movies then you may well indeed be better off going for a larger, ported SVS model or equivalent.

I don't think I've helped at all have I? :)
 

nluck83

Novice Member
Whilst I agree with the general notion that often the subs that speaker manufacturers come up with don't match those of sub specialists nevertheless KEF don't make junk. I have a KEF 10b and it's perfectly decent though I was given a very good offer for it!

One option you might want to think about is selling the Boston and actually getting a second KEF 8b!! You'll find all sorts of information about the benefits of dual subs online but the main one is to assist in smoothing out the inevitable peaks and dips you will get with the bass frequencies with a single sub - duals can definitely improve that - and so then improve the bass response throughout your media room. You talked about wanting 'tighter' bass - the KEFs are sealed subs and often this type are considered to have slightly tighter more controlled bass too.

At the end of the day though if you've got a medium/large room and you want a sub to crank it up for movies then you may well indeed be better off going for a larger, ported SVS model or equivalent.

I don't think I've helped at all have I? :)
My media room is 20ft long by 13ft wide. Its not a true media room though. Its ground level on slab, not in a basement so I have to deal with a sliding door and windows. That being said, the speakers sound great on the Denon. I am actually going to be adding 2 more ceiling speakers for a 7.1 setup. That being said, the room is big lol. The 8b sounds good but I have to crank the base on the Denon and on the back of the sub. Do you thing the 10B would be better? Or am I better off going with a ported SVS or equivalent? Would I be going 12" with that? My Boston sub has held its own but 20 year old sub is just old lol.

I am debating selling both and just going with a larger sub like you guys mentioned. I dont want to be spending a grand on a sub though. What would be the best bang for the buck for a room this size? Here is a pic I slapped together showing the setup of the room. Of course it isnt drawn to scale as I did it in Microsoft Paint lol
 

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Gasp3621

Distinguished Member
My media room is 20ft long by 13ft wide. Its not a true media room though. Its ground level on slab, not in a basement so I have to deal with a sliding door and windows. That being said, the speakers sound great on the Denon. I am actually going to be adding 2 more ceiling speakers for a 7.1 setup. That being said, the room is big lol. The 8b sounds good but I have to crank the base on the Denon and on the back of the sub. Do you thing the 10B would be better? Or am I better off going with a ported SVS or equivalent? Would I be going 12" with that? My Boston sub has held its own but 20 year old sub is just old lol.

I am debating selling both and just going with a larger sub like you guys mentioned. I dont want to be spending a grand on a sub though. What would be the best bang for the buck for a room this size? Here is a pic I slapped together showing the setup of the room. Of course it isnt drawn to scale as I did it in Microsoft Paint lol

If you can sell it then by all means go bigger as the room isn`t smallest and you seem to crave more impact. You live in New York i assume.

Depending of your budget and possibly size restrictions here are the best bang for buck ported models in US below 1k$, notice the M12 V2 is similar to PB2000 Pro but with much better pricing but the PB1000 Pro is still very good and more compact which is often important factor in living room. The M10 V2 has quite darn good performance for it´s size/price beating many 12" ported subs hands down. The M12 gets you deeper extension, more output in the deep and mid-bass region. Monoprice build quality is same level to SVS if not better using HDF over MDF and same 5year warranty. SVS has the best support/service and the "bill of rights" are something you don´t get with other brands read the link. However you will pay extra for it! SVS has 45-day home trial with free shipping and returns. All baked in to prices.





As for sealed model i would go straight with SB2000 Pro or HSU ULS-15 if you are sure you will only have one subwoofer. However two SB1000 Pro`s would be nice too if size matters, 1149$ deal for two. You won´t get similar tactile sensation with the sealed units vs. ported as they dig deeper with lot more output in the 18-36hz region and greater physical sensation when played louder, but that is not to say the sealed units wouldn´t great aswell. Especially after what you own now.

 

nluck83

Novice Member
@Gasp3621 Thanks for all the great information!!! Yes I am from NY, what gave it away? Lol.

Do you think the 8" Kef is big enough for this space? Would this be big enough for you if your media room was the same dimension? The size of the sub won't matter as where its living now really isnt in the way. Its behind a couch and side table so its really out of sight and mind at that point.

Would you go with ported or sealed in my setup? If so why would you choose that? I can't believe how much the subwoofer game has changed lol Based off what you have above I cant go wrong with a ported just like my Boston sub.

My question is, will I see a drastic difference going with one of the 10-12in subs over the existing 12" Boston sub I currently have? If so what would the actual difference be? It looks like this subwoofer isnt going for much of anything on the used market so I wouldn't be making a lot on it to say the least.
 

Gasp3621

Distinguished Member
@Gasp3621 Thanks for all the great information!!! Yes I am from NY, what gave it away? Lol.

Do you think the 8" Kef is big enough for this space? Would this be big enough for you if your media room was the same dimension? The size of the sub won't matter as where its living now really isnt in the way. Its behind a couch and side table so its really out of sight and mind at that point.

Would you go with ported or sealed in my setup? If so why would you choose that? I can't believe how much the subwoofer game has changed lol Based off what you have above I cant go wrong with a ported just like my Boston sub.

My question is, will I see a drastic difference going with one of the 10-12in subs over the existing 12" Boston sub I currently have? If so what would the actual difference be? It looks like this subwoofer isnt going for much of anything on the used market so I wouldn't be making a lot on it to say the least.

No i don´t think it would be adequate for the room, at least for my taste as i wasn`t happy with 10" sealed sub in smaller and larger rooms than yours. Yes you will see quite big difference with the models i linked. However i would think about could you go with two subwoofers right away and if one sub needs to be by the left side of couch then the 2nd sub would ideally go to front wall right corner or the other rear corner. Localization is going to be "issue" with one sub at one side which would be cured with dual subs so overall more room filling bass and the 2nd sub would also smoothen the bass response especially if you can place the 2nd at diagonally opposite front corner. The main reason people buy duals.

I`m using pc program simulation tool where i added your room dimensions and assumption is that you sit fairly center width wise of the room in the couch, is that correct? You have the better Audussey version also so it would be walk in the park to setup the dual subs and they don´t need to be equidistant to listener either as the XT32 has individual distance (=delay) setting for each sub and it also have quite effective eq so peaks should be flatten etc.

Actual difference firstly would be the sound quality of the bass as these are in different category to that cheap Boston especially. If you compare the specs you see there is massive difference in basically everywhere for example M10 V2 model; cabinet volume is much larger and heavier made from HDF, 500w vs. 100w power difference is massive, driver with big magnet is beefy one compared to that cheap toy in Boston so i wouldn´t be worried about it being just 10". The Boston falls quite steeply somewhere in the +30hz region where as the Monolith M10 V2 should have quite strong output down to 20hz with much lower distortion so all in all it should be quite dramatic difference (SQ & performance) making you hear/feel notes that you haven`t before. My money would be on 2x M10 V2 (assuming budget is tighter - ability to add two smaller over one large M12), but if you feel they are still too large as pair then the two SB1000 Pro`s would still kick butt and they are really compact. If we compare the measured performance they have more output in the mid-bass region so think of chest slam and the Monoprices due to big ported cabinet has massive edge in the deep bass region which is quite important for action/scifi flicks so you get the rumbling earthquake feeling with the ports moving lot of air. However i doubt either one isn`t going to be lacking if you buy two of them after coming from that Boston/small Kef! The feedback has been great for both really.

There is no reviews yet for M10 V2 as it just came, but the 10 THX is basically almost identical performance wise. The new one looks better. If you were to consider Monolith contact them by email and ask can they give you some better deal for one/two subs. In the UK members have got -15% discount code even for the new ones, you can mention this to them! Use your business man skills. :) Monoprice has sales quite often also so example independence day is coming quite soon after little googling so that could mean some type of sale. It´s hard to say the models are so new, but best bet is to contact them! For SVS there is no sales usually for new models after price jumps.

PS. There was indeed one review for M10 and the guy was quite blown away:

And the most detailed review with full measurements for the 10 THX model which is basically same. Keep in mind he tested one sub, the second naturally has lot of benefits.
 

nluck83

Novice Member
No i don´t think it would be adequate for the room, at least for my taste as i wasn`t happy with 10" sealed sub in smaller and larger rooms than yours. Yes you will see quite big difference with the models i linked. However i would think about could you go with two subwoofers right away and if one sub needs to be by the left side of couch then the 2nd sub would ideally go to front wall right corner or the other rear corner. Localization is going to be "issue" with one sub at one side which would be cured with dual subs so overall more room filling bass and the 2nd sub would also smoothen the bass response especially if you can place the 2nd at diagonally opposite front corner. The main reason people buy duals.

I`m using pc program simulation tool where i added your room dimensions and assumption is that you sit fairly center width wise of the room in the couch, is that correct? You have the better Audussey version also so it would be walk in the park to setup the dual subs and they don´t need to be equidistant to listener either as the XT32 has individual distance (=delay) setting for each sub and it also have quite effective eq so peaks should be flatten etc.

Actual difference firstly would be the sound quality of the bass as these are in different category to that cheap Boston especially. If you compare the specs you see there is massive difference in basically everywhere for example M10 V2 model; cabinet volume is much larger and heavier made from HDF, 500w vs. 100w power difference is massive, driver with big magnet is beefy one compared to that cheap toy in Boston so i wouldn´t be worried about it being just 10". The Boston falls quite steeply somewhere in the +30hz region where as the Monolith M10 V2 should have quite strong output down to 20hz with much lower distortion so all in all it should be quite dramatic difference (SQ & performance) making you hear/feel notes that you haven`t before. My money would be on 2x M10 V2 (assuming budget is tighter - ability to add two smaller over one large M12), but if you feel they are still too large as pair then the two SB1000 Pro`s would still kick butt and they are really compact. If we compare the measured performance they have more output in the mid-bass region so think of chest slam and the Monoprices due to big ported cabinet has massive edge in the deep bass region which is quite important for action/scifi flicks so you get the rumbling earthquake feeling with the ports moving lot of air. However i doubt either one isn`t going to be lacking if you buy two of them after coming from that Boston/small Kef! The feedback has been great for both really.

There is no reviews yet for M10 V2 as it just came, but the 10 THX is basically almost identical performance wise. The new one looks better. If you were to consider Monolith contact them by email and ask can they give you some better deal for one/two subs. In the UK members have got -15% discount code even for the new ones, you can mention this to them! Use your business man skills. :) Monoprice has sales quite often also so example independence day is coming quite soon after little googling so that could mean some type of sale. It´s hard to say the models are so new, but best bet is to contact them! For SVS there is no sales usually for new models after price jumps.

PS. There was indeed one review for M10 and the guy was quite blown away:

And the most detailed review with full measurements for the 10 THX model which is basically same. Keep in mind he tested one sub, the second naturally has lot of benefits.

The way my den is setup is my entire AV rack/gear is in the garage and I only have my TV on the wall. There is no other AV on the front wall where the TV is (i love the clean look). So if I went with a second sub I wouldnt be able to put on there. I would be able to put a second sub on the same wall as the first sub but opposite corner. Would there be any benefit for that location? Right now I share my media room with the kids who watch kids cartoons so I dont leverage it as much as I want right now because of their age. When they get older I would love to be using it to watch more movies and such. That being said, I would think a single sub, maybe 12", would hold me over at the existing location?

Yeah - I sit pretty much center on the wall where the sub is. I dont have any of the Audussey tools anymore that came with the amp. Plus the amp is in my garage in an enclosed rack 15-20 feet away so not sure if its to far? If it isnt, is it really beneficial to use the Audussey app? I used it on my old 7 year old Denon and wasnt impressed at all. If its worth it maybe I can buy a new mic with a cable extension?

Thank you on the indepth comparision against my Boston and Kef! What do you think I could sell the Kef for with it having minimal use? I would think $400 since they are $600 new? You have def sold me on the fact my existing subs are to small for the space. That is kind of the vibe I got when using them! I will be on the lookout for sales and will most def hit up Monoprice for a price. Is a good idea to stay away from used Monolith and SVS subs on ebay?
 

Gasp3621

Distinguished Member
The way my den is setup is my entire AV rack/gear is in the garage and I only have my TV on the wall. There is no other AV on the front wall where the TV is (i love the clean look). So if I went with a second sub I wouldnt be able to put on there. I would be able to put a second sub on the same wall as the first sub but opposite corner. Would there be any benefit for that location? Right now I share my media room with the kids who watch kids cartoons so I dont leverage it as much as I want right now because of their age. When they get older I would love to be using it to watch more movies and such. That being said, I would think a single sub, maybe 12", would hold me over at the existing location?

Yeah - I sit pretty much center on the wall where the sub is. I dont have any of the Audussey tools anymore that came with the amp. Plus the amp is in my garage in an enclosed rack 15-20 feet away so not sure if its to far? If it isnt, is it really beneficial to use the Audussey app? I used it on my old 7 year old Denon and wasnt impressed at all. If its worth it maybe I can buy a new mic with a cable extension?

Thank you on the indepth comparision against my Boston and Kef! What do you think I could sell the Kef for with it having minimal use? I would think $400 since they are $600 new? You have def sold me on the fact my existing subs are to small for the space. That is kind of the vibe I got when using them! I will be on the lookout for sales and will most def hit up Monoprice for a price. Is a good idea to stay away from used Monolith and SVS subs on ebay?
So you mean both subs would be in rear corners? It would work yes as you wouldn`t locate the sub anymore and if you can sit just a little bit left or right in the couch then the response looks even better. As you have also kids/wife sitting there so wouldn´t go waste. :)

I don´t think 15-20feet is too far away, just get long enough shielded subwoofer cables. Amazon Basics or Monoprice sells some affordable ones too, doesn´t need to be super exotic brand. If there is cable extender for the Audussey mic then the distance isn´t issue.

You definitely need to buy specific Audussey mic for the X3500H from Amazon or which ever has it good price and also order boom arm mic stand with clipper for the mic if you don´t have the cardboard mic stand which came with the Denon. If you have the app then by all means run he Audussey setup through it. There is some things to tweak with it though, but nothing too hard.

I have no idea what they ask for the Kef and how easy it´s to sell there in US. This is UK forum so no idea really. If it`s very new with transferable warranty then it could be easy to sell. Not sure which places are best but little googling might help.

I wouldn´t buy used sub without transferable warranty, too risky. If you go with new one then as i said contact them via email and ask discount code as you have been hearing better deal could be possible. :)
 

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