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Brand new PMC Twenty5.23 speakers

B

babolat

pfm Member
Hi team,

I’m a proud owner of a brand new PMC Twenty5.23.

During the week-end I unpacked them and I started listening to my CDs. With “some” surprise, I didn’t like the result, they sounded kind of boxed and not coherent medium/bass with the speakers.
I read the manual and there is written that for a brand new pair of speakers there is the need of at least 50+ hours of running in.

Not really sure, I remember thread saying that a couple of hours are enough for this task.

Any little advice?


P.S. my system: Naim CDx2, Nac282 and Nap200.

Thanks,
Marco
 
Hmm that’s what I experienced on the previous versions the 20.23. But give them a week of running...
 
A 5.25" midwoofer will struggle with standard SPL levels in a reasonably sized room particularly if the crossover includes a fair chunk of "baffle step correction" which is likely. I used to have 5.25" midwoofer in a DIY TL cabinet that was designed to be placed flat against a wall which helped clean up and boost the bass by 4-5 dB or so. Even with this help the SPL needed to be held to a lower than standard levels. Subwoofers would have been a big help.

A few minutes is typically all that is needed to loosen up driver suspensions after manufacture but this is to some extent a function of the materials used. What can take longer is for the brain to adapt to the sound being "normal" but this tends to relate a fair amount to the indirect sound of the speakers in the room, a lesser amount to the direct sound and little to nonlinear distortion/resonance. For example, if the SPL you wish listen at in your room is too high for the 5.25" midwoofer to handle then no amount of running in is going to make any difference. To check this is the case, reduce the level and if what you are picking up on reduces or disappears then this would be an indication. However, if the room is acoustically poor then reducing the level can also clean up the sound with well behaving speakers and so this is not conclusive.
 
There is a trick you can use to run in speakers. Put them facing each other in close proximity. Reverse one of the speaker leads (so they are now antiphase).

Put a CD on repeat and leave them doing their thing for however long you are prepared to wait. Being wired antiphase will vastly reduce the noise in the room but the speakers will be getting a good work out.
 
I listen to a moderate to low level of SPL and I checked, both speakers are the same.
I'll run them in for some hours, unfortunately I cannot place them running with a CD on a repeat mode.
 
babolat said:
Hi team,

I’m a proud owner of a brand new PMC Twenty5.23.

During the week-end I unpacked them and I started listening to my CDs. With “some” surprise, I didn’t like the result, they sounded kind of boxed and not coherent medium/bass with the speakers.
I read the manual and there is written that for a brand new pair of speakers there is the need of at least 50+ hours of running in.

Not really sure, I remember thread saying that a couple of hours are enough for this task.

Any little advice?


P.S. my system: Naim CDx2, Nac282 and Nap200.

Thanks,
Marco
Click to expand...
babolat said:
Hi team,

I’m a proud owner of a brand new PMC Twenty5.23.

During the week-end I unpacked them and I started listening to my CDs. With “some” surprise, I didn’t like the result, they sounded kind of boxed and not coherent medium/bass with the speakers.
I read the manual and there is written that for a brand new pair of speakers there is the need of at least 50+ hours of running in.

Not really sure, I remember thread saying that a couple of hours are enough for this task.

Any little advice?


P.S. my system: Naim CDx2, Nac282 and Nap200.

Thanks,
Marco
Click to expand...
I did not like my PMC 25/26 speakers after 100 hours and got a refund. I think the reviews are totally inaccurate
 
Disbeliever said:
I did not like my PMC 25/26 speakers after 100 hours and got a refund. I think the reviews are totally inaccurate
Click to expand...

PMC 25 or 26 are completely different animals, nothing to share with the 23, that's why I bought the 23. Even if it seems a "poor" speaker, it's the best of the line, believe me or not. The only one receiving so many important awards.
 
Hopefully you had a chance to demo them with Naim gear before buying them?
I do think they benefit from a decent length of running in. Ultimately they are never going to be everyone’s choice. I like em. A bit hot at the treble end, but a decent enough bass end for their size.
Room-speaker interaction will always play an important role.
 
Yes the twenty 26 were demoed with a Naim & Arcam amp the top & bass are not bad ,its the mid which is the main problem with male & female voices at realistic levels.
 
Had these on demo before Christmas, where a top and bottom heavy sound, even with a smooth class A amp, didnt like them. Bought Kef R5's instead and saved some dollars at the same time.
 
Purité Audio said:
Did you have two pairs of identical loudspeakers?
Keith
Click to expand...

Behave now, Keith! :D

For what it’s worth, when I worked as a loudspeaker designer, we did the test you’re thinking of - namely comparing a ‘box-fresh’ pair of speakers with a pair that we had run in with pink noise for a constant 48 hours.

The differences were not subtle and it took a good week to ten days of ‘normal’ use before the box fresh pair caught up with the others.
 
babolat said:
I listen to a moderate to low level of SPL and I checked, both speakers are the same.
I'll run them in for some hours, unfortunately I cannot place them running with a CD on a repeat mode.
Click to expand...
Plug in a tuner and leave them playing Radio 3 or 4 quietly for a week.
 
stevec67 said:
Plug in a tuner and leave them playing Radio 3 or 4 quietly for a week.
Click to expand...
You need something close to full displacement and not a tiny displacement in order to loosen up the suspension but this typically takes a few seconds to a few minutes. When manufacturers match pairs of drivers this step is obviously a requirement so they know what is required for their drivers. If you run a driver for 48 hours close to full extension it will get hot and change it's properties. They will normally revert to broken in values when the driver has been left to cool. This is only referring to physical breaking in of the driver rather than how the brain learns to process sound over time. One also cannot state with absolute certainty that all drivers will need only a few minutes to break in because the possibility exists some may use material that do not behave in the same way as those that have usually been used by driver manufacturers.
 
h.g. said:
If you run a driver for 48 hours close to full extension it will get hot and change it's properties. They will normally revert to broken in values when the driver has been left to cool.
Click to expand...
Most hifi speakers don't see this ever in their lives. How often do you run your speakers near flat out? For 48 hours? You physically can't do this with something like a Tannoy HPD or a big JBL unless you lend it to a local disco operator for a few weeks.
 
stevec67 said:
Most hifi speakers don't see this ever in their lives. How often do you run your speakers near flat out? For 48 hours? You physically can't do this with something like a Tannoy HPD or a big JBL unless you lend it to a local disco operator for a few weeks.
Click to expand...
Ask beobloke for the details not me. I was suggesting the OP simply repeats what driver manufacturers do to break in drivers. They would typically use close to full displacement at a low frequency for a few seconds to a few minutes. What is being done is to shift/break whatever bonds are going to be shifted in use and that will require close to maximum stress. Small displacements are not going to stress the material sufficiently to do anything much. I am of course referring to real physical effects rather than audiophile ones which may lead to requirements of hundreds if not thousands hours for break in and possibly at displacements too small to significantly stress the relevant materials. It is for the OP to decide what fits with his way of seeing things.

PS When I had a transmission line with a 5.25" midwoofer it went close to maximum displacement much of the time due to insufficient SPL. The OP says he listens relatively quietly and so may not have the same issue.
 
I’d ask the dealer for my money back immediately, and have him take the speakers back. The money you paid him didn’t need running in before it showed up in his bank account. Tell him that if he thinks it’s a run in issue, then by all means he can do the running in, and dem you the speakers after they’re run in. Then if you like them, you can buy them.
 
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