noob question crossover ditton 15xr

[Axelleke]

Hi all
Sorry for my poor English.
I am just exploring this new hobby.
I want to give some new life to my Celestion ditton 15XR speakers and learn something in the proces.
The sound of the tweeter is harsh. Soft music like piano is good, but Queen for example is a audiophile mess. The human voice does not sound nice.
It sounds better now with my new (old) Denon PMA-1500R than with the Marantz amp I tried first. But still.
I opened the speakers and found a crossover. Hope you can see the picture I included.
I guess the original 4.7uF cap needs to be replaced. But with what?
I found this site http://www.humblehomemadehifi.com/Cap.html and I wonder if I should bye a Jantzen or MUndorf cap 20-50 euros), or just stick with much cheaper caps (like the Daytons). The advantage of Humblehomes suggestions is that i could try to tweek the sound to my liking (based on his description) or is this just an illusion?
Just curious: what type of crossover is this in the 15xr? First order, second ...
Also: I found conflicting information over the crossover frequency of this speaker. Some think it is 2500, others 3000 but based on the 4.7 uF, I suspect it is rather 4000HZ. What do you guys think? I suspect there is confusion online between the ditton 15 and 15xr. Any ideas about this?
And last but not least.
Maybee I could replace the old crossover with something like this:
Dayton Audio XO2W-3.5K 2-Way Speaker Crossover 3,500 Hz
Are these a good alternative for beginners? The do not have a 4000Hz it seems, so i would have to tweek this as well?
Thank you very much.
Axel

 

[swechsler]

I don't have an opinion on the type of capacitor you choose, although many AKers have been happy with Dayton caps. But don't replace the crossover, that's opening a can of worms. Generic crossovers are designed based on generic drivers with an "ideal" impedance (that is, drivers whose impedance at the crossover frequency exactly matches the listed impedance, which is rarely the case, since impedance is a curve, not a single value). Celestion designed the crossover based on the drivers used in this design.

 

[Stuart Pedaso]

Hi, Axelleke. Welcome to AK.

Just curious: what type of crossover is this in the 15xr? First order, second ...

From your photo, there appears to be a second order high pass filter for the tweeter and a first order low pass filter for the woofer:

Also: I found conflicting information over the crossover frequency of this speaker. Some think it is 2500, others 3000 but based on the 4.7 uF, I suspect it is rather 4000HZ. What do you guys think? I suspect there is confusion online between the ditton 15 and 15xr. Any ideas about this

An online review by Audio Nostalgia of the original Ditton 15 reports the crossover at 3 kHz.

A review of the Ditton 15XR by stereonomono reports the crossover at 2.4 kHz. Ditton 15XR was redesigned with all new drivers, which could reasonably account for a change to the crossover frequency.

Both reviews appear to be well researched.

You can't really calculate the crossover frequency from a capacitor value without knowing actual driver impedance at the suspected frequency (the exact issue pointed out by swechsler). Published performance specs for 15XR are impressive enough to suggest that the engineers did a decent job designing the stock crossover.

 

[northpaw]

I have a Ditton 130 with those same black caps, including one 4.7µF. They measured poorly (drifted up, and elevated Vloss), presumably due to age. See this post: https://audiokarma.org/forums/index...ion-owners-thread.804597/page-4#post-13406410

I think any replacement, including a new non-polar electrolytic or a film cap, would provide significant improvement in sound. Only you and your ears can decide if a more expensive cap is worthwhile, and I have never bought one so I can't provide an opinion, but a film cap costing just a few dollars, such as a Dayton (I haven't used them) or an Audyn (I have used them), are likely to provide a significant improvement in performance.

BTW, welcome to AK.

 

[Axelleke]

Tankx for your help!

But don't replace the crossover, that's opening a can of worms.

Okay, I understand your point. I won't do it

From your photo, there appears to be a second order high pass filter for the tweeter and a first order low pass filter for the woofer:

Wow! This makes things much clearer to me. I did not even know you could have a second order for the tweeter and something completely different for the woofer. I am gowing to print your drawing and hang it on the wall .

You can't really calculate the crossover frequency from a capacitor value without knowing actual driver impedance

point taken

A review of the Ditton 15XR by stereonomono reports the crossover at 2.4 kHz.

I also found that stereonomono review. Well documented indeed. But others think the crossover is higher. As an example this statement on another forum:

"I think that what you are running into here, Louis, is the Ditton 15 used the Celestion HF 1300 Tweeter, and the later 15XR used a more regular soft dome.

The Ferrofluid Morel CAT 298 soft dome is a good replacement for most of the old tweeters, being available in 94mm, which can help.

BUT, the HF 1300 crossed over much lower than regular soft domes. Maybe 1800Hz as opposed to the sort of 3.5kHz that would suit the Morel better.

So the 15XR had a different crossover. 4.7uF rather than 12uF in the treble section. I can't comment on coil values unless you measure them."

I was considering replacing the tweeters with the Morel, and that is how I stumbled across this quote. But now I have changed my mind.
I actually like the sound of the 15XR very much for piano, guitar, jazz, soft music, male voices, ... In fact: the more I listen to them, the more i like them. It is not perfect, but nice to listen to..
I wanted something else because I also like Queen, Pink Floyd, Red hot chili peppers .... And for this more complex music these speakers do not seem to work. Much to harsh tweeter whenever it gets loud or complicated.
I think now I want to keep things original, and see where I can bring the sound with new caps. Much cheaper and it is a quest that looks fun. I will keep you posted.

BTW, welcome to AK.

Hi, Axelleke. Welcome to AK.

Thank you, this is a friendly forum with some nice helpfull people
Nice Hobby you all have!

 

[coonmanx]

If you recap and then decide that you still don't like the tweeters then maybe consider trying some replacements from Parts Express like these...

https://www.parts-express.com/dayton-audio-dc28f-8-1-1-8-silk-dome-tweeter--275-070

Or even these if you want to go cheaper...

https://www.parts-express.com/goldwood-gt-525-1-soft-dome-tweeter--270-182

Do the recap first and then report back. I used Dayton Polys in my Speakerlab 1's for the recap...

Those silk domes at $20 a pop would be a good bet but I have also used some Goldwood tweeters before with good results, just not those particular Goldwoods.

 

[rothwellaudio]

Replacing the non-polar electrolytic with a polysomething is worthwhile, but I suspect the harsh sound is due to your amplification, not your speakers.

 

[Axelleke]

I think any replacement, including a new non-polar electrolytic or a film cap, would provide significant improvement in sound. Only you and your ears can decide if a more expensive cap is worthwhile,

Sounds good. I will try the cheaper ones first!

Replacing the non-polar electrolytic with a polysomething is worthwhile, but I suspect the harsh sound is due to your amplification, not your speakers.

Interesting. To be honest, I read conflcting information about this. Some say it is the capacitors, some say the tweeters are inferior, some say these speakers are to blame, and now it appears there could be a problem with the amp?
Could you explain this point in more detail? I am new to this and just curious and want to learn interesting things or different opinions.
But ... I would not expect a Denon amp to sound harsh? (I do not want to start a war here, but I do want to here if and how different amps can provide different sounds)
What do you guys think about this?
I guess I will have to listen myself what the result is after replacing the caps?
Thank you

 

[rothwellaudio]

...now it appears there could be a problem with the amp?
Could you explain this point in more detail?

My experience has been that speakers may sound bright or dull etc., but that's just a difference in tonal balance. When busy music gets confusing or sounds nasty it's the amp at fault. A good amp can make even modest speakers sound good. I may not have mentioned it but you did make this comment, quoted below, which suggested to me that maybe the amp is to blame:

It sounds better now with my new (old) Denon PMA-1500R than with the Marantz amp I tried first.

Maybe it would sound better still with a different amp.

 

[Axelleke]

Maybe it would sound better still with a different amp.

I hate to think I may have bought the wrong amp