Kef TDM45B - Awful Sounds

[soundB]

I have a Kef TDM45B subwoofer, which sounds great for the most part. However, every once is a while it will emit a godawful sound that I can only described as paper crumpling on steroids. I recorded a couple of samples with my phone, not sure how much justice they'll do but might at least give an idea of what I'm talking about:
Sample 1
Sample 2

I recently spent few hundred dollars to have the plate amplifier's transformer repaired so I am remiss to give up on this subwoofer.
I hoping someone here will be able to help me out.

So far I've done the following, troubleshooting wise:

• I've adjusted the volume, crossover frequency, and toggled THX to no avail.
• I took apart the subwoofer to inspect for any damage or tears on the speaker and didn't see anything obvious.
• I bought a cheap replacement speaker on Amazon (Pyle PLW15RD) with the hopes that I could at least continue to use the enclosure and plate amp. To my surprise, the replacement exhibited the exact same problem.
• I found this awesome site with samples of different frequencies. I tried them all out and discovered that everything sounded good until I hit 20 Hz (and below), then I started to replicate those awful sounds.

The only thing I can think to do now is to drop the volume until I no longer have any distortion at 20 Hz (and below) but that will eliminate most of the bass this subwoofer puts out so that's no fun! Any help is appreciated. Thanks in advance.

 

[j_garcia]

I think you've identified it already, the issue is the sub cannot handle the lowest content. It can be clearly heard in your recording. I found the manual and it lists the bottom end of the sub as 35hz, which is not very low. I would say it is time to look for a new sub and one that is capable of at least getting to 25Hz, but to eliminate what you're hearing completely, one capable of some level 20Hz performance.

 

[William Lemmerhirt]

Well from what I could find. That sub was built between 1994 and 2001. It’s very old by subwoofer standards as they’ve improved considerably since then, and respectively KEF was never known for amazing subs. I also see that yours has a listed FR from 35hz and up. That’s much too high for a subwoofer playing modern soundtracks that can easily hit single digits, and routinely have extension down to 20hz.
The sound that I heard in your samples sounded to me like the driver was bottoming out, or in other words running out of excursion. It will only tolerate that so many times before it’s ruined.
Imo, you’re due for an update as even some of the more modest offerings today will outperform the kef in every way.
Also. Just for future reference, dropping a random driver into an enclosure is a recipe for disaster. Amps/drivers/enclosures are carefully chosen to work together.

 

[soundB]

Thanks for the responses.

I inherited my home theater from the previous owner of my house so I really don't know much about the equipment. All I know is he dropped a ton of money and everything (except the subwoofer) still sounds great. Based on that, I was so focused on looking for a problem, I never stopped to think that the subwoofer was simply deficient by today's standard.

I now realize I need a new subwoofer if I want to solve this issue but is there anything I can do somewhat alleviate it in the meantime? I use an Onkyo TX-NR1009 receiver if that helps. I went through all the settings and couldn't seem to find anything useful. In the subwoofer equalizer, I was able to drop 20 Hz to -6 dB but it didn't seem to make much of a difference. Perhaps if I increase all the other frequencies to +6 dB and drop my subwoofer volume, it might have more of an effect?

It's really too bad that I didn't realize this subwoofer wasn't worth repairing before I dropped money on fixing the plate amp, that money could've helped me toward my new purchase

As for putting a random speaker in my enclosure, I realize that wasn't wise to do but I was getting desperate for some sort of solution or even clue.

 

[William Lemmerhirt]

Well as far as the random driver, I get it. Probably cost about 30 bucks so wth!(unless you know better lol)

I guess the only thing I can say is just to lower the overall level. I would at least run audyssey.(the 1009 is getting old too fwiw). Then see if that’s an improvement. Since the subwoofer really can’t do anything below say 30hz lowering the eq range from there would be better than 20hz where it’s not really doing anything except puking it’s guys out.
If you don’t really want to run audyssey, at least try to see if it’s close to being level matched. Even with a(hate to say it) phone SPL meter app. Part of the issue is it might be running way too hot. That could be due to taste, or getting used to it over time, or even trying to just get more deep bass. The short version is a long run solution.
New sub....

 

[lovinthehd]

We do usually encourage people to run stuff by the forum before spending $

Only thing I can think of to cut lower frequencies somewhat would be to re you using a double bass setting in the avr (Onkyo calls it double bass too IIRC). If you're using the graphic eq you're trying without Audyssey I assume....and I'd try William's suggestion to run it to see if it changes things up.

ps clarification that bit about the double bass should say if it's on to turn it off....

 

[j_garcia]

Agree with William, that sub probably struggles with anything below 25Hz, and pretty much everything has content in that range. Try dropping the next frequency up in the EQ down a few dB too.

There's also subsonic filters, which you could run in line with the sub's connection, but again, money toward Band-Aids instead of replacing, which is where the real benefit will be.

 

[soundB]

Thank you all.

I didn't even know about Audyssey, I'll definitely try that out and report back!

Unfortunately, I hadn't yet found this forum when I was deciding whether or not to repair the plate amp.
I did ask about whether I should go ahead with the repair on Reddit's /r/audiophile and, unfortunately, a response I received there convinced me to go ahead with the repair (I was originally on the fence).
Oh well, I'm here now and am very appreciative of the knowledge you're all dropping.

I'm a bit uncertain as to how Double Bass could help, could you please elaborate?
From the Onkyo manual: "Turn this setting on to boost bass output by feeding bass sounds from the front left, right, and center channels to the subwoofer."

Subsonic filters would definitely "solve" my issue but, as you said, not really worth spending more money on a band-aid solution (especially considering they seem to quite expensive).

 

[lovinthehd]

I was saying if double bass is on to turn it off to help out (but sure didn't make that clear now that I look back)

r/audiophile is full of lunacy IMO

 

[William Lemmerhirt]

I was saying if double bass is on to turn it off to help out (but sure didn't make that clear now that I look back)

r/audiophile is full of lunacy IMO

Agreed. Only spent enough time browsing over there to know that I’m not going back. Lol.

At least @soundB is here now.
The journey is different for everyone.

 

[soundB]

Somewhat relevant question:
I've just been browsing my local Kijiji to see what's out there, for curiosity's sake.
A lot of the subwoofers I see on there have a similar lower frequency range as my subwoofer.
That means they'd all suffer from this same issue then, right?
What is the point of any of these? Is it that movies and TV shows emit a lot lower frequencies than music, or...?

 

[Pogre]

Yup. Run Audyssey (hopefully you still have the mic). It might help cut some of those lower frequencies for you automatically. Don't beat yourself up over the amp repair. Just chalk it up under "oops, now I know better!" and start planning for a new sub. We've seen far worse here. We all gotta start somewhere. I'm glad I stumbled across this place early on. These guys know their stuff and I appreciate the objective-based scientific slant with reviews and advice. There's a lot of woo out there and a person can spend some serious money on pure foolishness following bad advice. Don't ever listen to any of the cable mystics. They're the worst...

Welcome to Audioholics!

 

[Trebdp83]

Double Bass would only be selectable when Fronts are set to FULL BAND. Some set their towers to full band but find bass lacking so they can turn on double bass and send the bass to a subwoofer as well. “Cable Mystics”, that’s funny.

 

[lovinthehd]

Somewhat relevant question:
I've just been browsing my local Kijiji to see what's out there, for curiosity's sake.
A lot of the subwoofers I see on there have a similar lower frequency range as my subwoofer.
That means they'd all suffer from this same issue then, right?
What is the point of any of these? Is it that movies and TV shows emit a lot lower frequencies than music, or...?

Can you give some examples of make/model? Yes, for music you may not need a sub that digs as low as you would for movies generally (or you can like music that digs that low, too). Smaller subs generally have limits like that, physics does impose limits. Personally if it can't do 20hz decently it's not a sub.

 

[lovinthehd]

Double Bass would only be selectable when Fronts are set to FULL BAND. Some set their towers to full band but find bass lacking so they can turn on double bass and send the bass to a subwoofer as well. “Cable Mystics”, that’s funny.
View attachment 45563

It's been ages since I checked it out on my old Onkyo....

 

[Pogre]

Somewhat relevant question:
I've just been browsing my local Kijiji to see what's out there, for curiosity's sake.
A lot of the subwoofers I see on there have a similar lower frequency range as my subwoofer.
That means they'd all suffer from this same issue then, right?
What is the point of any of these? Is it that movies and TV shows emit a lot lower frequencies than music, or...?

Some examples of what you found?

Most modern subs with limitations will have a high pass built right in to prevent the driver from trying to do what it can't. Deep bass doesn't come cheap. Those on a budget would still like more bass than their speakers are capable of, but can't afford a true sub. Something that dogs down to 30-35 hz is still a lot better than your typical bookshelf or even a lot of towers.

That's not to say there aren't some competitively priced subs out there capable of hitting 20 hz, but you gotta know what to look for. A lot of them don't. Right now SVS and Hsu have some good offerings that don't cost an arm and a leg. Where are you located?

 

[j_garcia]

What is the approximate budget? 20Hz won't be found in the lower end of the spectrum, but we can certainly help find something that works and hopefully doesn't break the budget.

 

[soundB]

I'm located in Edmonton, AB, Canada.

For example, this Klipsch Black Label 10" subwoofer has a lower limit of 32 Hz.
Obviously, this is middle-of-the-line subwoofer but its not that cheap (especially considering it's used).

Then there's this SVS SB-2000 Subwoofer, which has a lower limit of 19 Hz.
As expected, it's quite a bit more expensive. I think if I was willing to drop that kind of money I'd be buying new though.

I don't really have a budget at this point. I already spent $300 repairing the plate amp so I'm a bit hesitant to spend more money at this point (hence why I'm trying to find a workaround). When I do decide to buy another subwoofer, I guess I'll make my budget what it needs to be to avoid having this problem again (within reason).

 

[soundB]

Run Audyssey (hopefully you still have the mic).

I do! I was wondering what this thing was.
Fortunately, the previous owner was very diligent in leaving me everything, down to the carboard boxes the speakers came in.

 

[Pogre]

I'm located in Edmonton, AB, Canada.

For example, this Klipsch Black Label 10" subwoofer has a lower limit of 32 Hz.
Obviously, this is middle-of-the-line subwoofer but its not that cheap (especially considering it's used).

Then there's this SVS SB-2000 Subwoofer, which has a lower limit of 19 Hz.
As expected, it's quite a bit more expensive. I think if I was willing to drop that kind of money I'd be buying new though.

I don't really have a budget at this point. I already spent $300 repairing the plate amp so I'm a bit hesitant to spend more money at this point (hence why I'm trying to find a workaround). When I do decide to buy another subwoofer, I guess I'll make my budget what it needs to be to avoid having this problem again (within reason).

Ported subs are generally more capable of deeper bass than sealed designs. Pretty much the only reason to go sealed is if space is an issue. Even the SVS PB1000 Pro is a very capable sub for the price range and size. If you have a small to medium room it'll perform well. I think I'd choose it over the SB2000 Pro.

In general avoid Klipsch for subwoofers. They're better speaker manufacturers than subwoofers, and you gotta be careful which of their speakers you get too.

Why don't you run Audyssey real quick and see if that helps. It just might. Let us know how it works out. That might at least get you up and running while you save and shop subs.