Sub with pmc’s?

I have a 252/300 powering pmc twenty5.26, I’d like to hear from anyone who has tried using a sub to enhance bass frequencies with pmc Twenty5.26’s, a worthwhile upgrade? How did the sub alter the sound? Also I’m thinking of an active sub (pmc tle1), how do I get the signal to it? Via the Supercap? Thanks

I’ve got a MJ Acoustics Reference 100 sub connected with my 23is and Star.
I’ve got it set at 42Hz and feel it adds a Bit at the bottom end, Though the bass would be ok without it I already had the sub so thought might as well use it.
Got to be careful you don’t set it too high volume , just enough to add a subtle thump when required.

Whilst the smaller PMCs could well benefit from a sub, that seems less obvious a need with the 26, though I’m not sure of it’s roll- off point. Having said that, PMC’s top speakers, MB2 and BB5, both of which go lower than the 26 are available with subs (MB2XBD & BB5 XBD), though they are pretty rare outside recording studios. If the sub isn’t a transmission line design (and I think none other than PMC’s are), I don’t know how well the sound character would balance, though if used properly only below the roll-off point it might not matter.

I have the earlier Twenty 26’s and have tried my Monitor Audio GS sub in the system more out of curiosity than anything else, the difference is minimal to be honest, very dependant on the type of music you listen to.

For me the subs energy/output doesn’t really match what the 26’s put out, if that makes any sense, it’s okay to have one in the system, not sure I would rush to spend £1-2k for the benefit it brings, worth borrowing one if that’s an option just to try.

Sorry can’t help with the connecting it to your system, from memory I think I picked up a feed from my hicap.

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Thank you Silverback, the speakers certainly have bass I just find cranking the volume up a bit suddenly makes the bass being felt as much as it is heard- very real life, I was wondering if that effect could be had at lower volumes with a PMC sub.
… on another matterI see you power with a 202/200 combo, I used same (also with NAPSC and Hicap-DR before recently upgrading) may I ask if you have ever had your 26’s driver(s) hit the bump stop, if so at what O’clock on the volume dial?

The problem at low volume levels is not the speakers, but as far as hearing is concerned it is your ears losing sensitivity at frequency extremes as volume is lowered, while for feel it is simply your nerve sensitivity, or if through clothing or furniture it is the energy needed to get them to vibrate, and I would not expect to feel bass at low sound levels unless boosted above the sound level of the rest of the music, which if overdone would be very unnatural. Ear roll-off, can be compensated for with a “loudness” control, which would also increase the chance of feeling the bass, but the ones that are often fitted to cheap music systems are crude affairs, simply on or off, not related to actual sound level. You could use tone controls if you have them - though again crude as they aren’t tailored to the loudness frequency contour. (NB ears are also less sensitive to treble at low sound levels, so to be correct that should also be boosted.)

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Hi Jonny, I totally understand what you are saying, my 26’s sound better as the volume is increased and if I’m honest I do use the system at anti social levels but not all the time.

Innocent bystanders raises some very valid points and I agree, what the sub may allow you to do is lift the bass to how you like it as you have a gain control on the sub which makes it very flexible, my GS is very controllable having the option of a sub lower filter, plus various levels of roll off adjustment at the bottom and the top of its frequency range as well as the normal gain control, so a lot to tweak, so to speak, not sure all subs offer this level of control.
The answer to have I had the drivers hit their buffers, not as far as I know but to be fare the 200dr is not really totally comfortable at the levels I use from time to time, hence why at the moment my Bryston is in the rack, which works much better at higher levels.
I just think the 26’s “like it up em” so to speak, best in big rooms with powerful amplification, l have the power unfortunately don’t really have a big enough room to probably enjoy them at there best, hope this helps.

Given that open transmission lines are 4th / 5th order bass alignment, how to integrate the timing could be, well, “an interesting question”!

Hi Silverback again - Innocent_Bystander underlines the symptoms I appear to be experiencing (thanks Innocent_Bystander), I was kind of wondering whether I could employ a sub for less loud sessions to enjoy the bass that the PMC’s put out as the volume increases - for loud sessions I could simply turn the sub off… I’ll have to take the oft given advice and try and get a loaner sub.
My 26’s start to bounce of their bump stops during songs with heavy use of kick from or hard dance tracks when the dial is turned up to around 10pm (NAC252/300-DR) - both channels - which surprised me as I thought the 26’s should handle such bass, heavy and sudden as it is…

If you can borrow a loaner that would certainly help, I have just helped my friend install a REL sub to his system, not sure which model but it was around £1k, he runs Twenty21’s, it has made quiet a difference and he’s very happy with the results.
Little surprised your 26’s bottom out that often, I used to run the 200dr at 10 o clock, the Bryston is happy to run at 11 o clock anymore and my ears start to complain! Wouldn’t have expected that from a 300, maybe other users of the same setup could comment, seems strange.
I do find modern content seems to be recorded at higher levels which maybe not be helping the issue.
If I use the turntable the system is happier at higher levels, it’s the dynamics that obviously do the damage, that’s the issue with subs, finding one that deliver music well and can match the dynamics of the 26’s, getting 12-15” to move quickly is a challenge, could be why the PMC sub uses two smaller driver?

You are more than welcome to borrow mine to try but guessing may not be that practical depending where you are based in the country👍

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