As bypass caps are generally only .01uF, the change in capacitance is less than the tolerance of the primary caps. On the 6.8uF tweeter cap, the change would be at most 0.15%. The tolerance on the 6.8uF cap is usually around +/- 5%.
The tolerance of the capacitors doesn't relate to how much it can be heard.
In a case when it is audible, wouldn't the value of capacitance be potentially more audible than other things?
In a case when it is audible, wouldn't the value of capacitance be potentially more audible than other things?
I must be missing something in your comments, as I do not understand what you are trying to say. You asked: "Have you experience with this when done in a way that doesn't change the value of capacitance?" This was in reference to adding a 0.01uF bypass capacitor, in parallel, to a 6.8uF capacitor, that will have a +/- 5% tolerance, and thus an actual value between 6.46uF and 7.14uF.
Don't know what this means either. "The tolerance of the capacitors doesn't relate to how much it can be heard." ???
Or this: "In a case when it is audible, wouldn't the value of capacitance be potentially more audible than other things?" ??? The value of capacitance would determine the frequencies that are allowed through to be reproduced by the tweeter. Is that what you are asking?
To perhaps put his remarks into context, AllenB has previously stated that bypassing can bring mixed results, and that he uses single caps where possible.
Your high pass filter requires no "upgrading" in my opinion. You might like to try the effect of substituting MKP capacitors for the electrolytics in the low pass filter. Changing the large laminated core inductor for an air core of comparable dc resistance would be expensive, and the resulting reduction in bass distortion would be small compared to the 3% or so that is typical of domestic loudspeakers.
Your high pass filter requires no "upgrading" in my opinion. You might like to try the effect of substituting MKP capacitors for the electrolytics in the low pass filter. Changing the large laminated core inductor for an air core of comparable dc resistance would be expensive, and the resulting reduction in bass distortion would be small compared to the 3% or so that is typical of domestic loudspeakers.
I don't know AllenB at all, but I know of many talented speaker designers who are big believers in bypass caps. Danny Ritchie of GR Research. Bob Reimer of CSS audio. Paul McGowen of PS Audio. Tony Gee of tg-acoustics (humble homemade hifi). All of them are big believers in high quality capacitors in general, and bypass caps in particular.
The issue with crossover upgrades, like many upgrades, is the law of diminishing returns. You could drop hundreds of dollars on air core inductors, high end caps and resistors and would you really hear a difference? Not sure. The other issue, is that these low cost provider components in my QA 3050s are physically very small (they even mounted the resistors vertical!) so the boards they are mounted on are very small. It would be tough to fit many upgrades on the existing crossover boards. It would be easier to build entire new boards and wire point to point if you really wanted to pursue it.
Mills resistors which are 1% tolerance & low inductance are only £6 to £10 each for the 12W versions over here.....
Decent air cored inductors by say Jantzen in a 13AWG even for the biggest 11mH are £123..as low as 0.01mH in 13AWG are £6...
& Mundorf caps in their classic range start at £4 for a 1uf...
No need to spend £100 on a single component......the most I spent was £13 on each 10uf 250v CSA ClarityCap...on the tweeter section..
& yes usually new boards are needed....& then an external box to house the board...😀..it sort of snowballs!!!
I did a write up on modifying my speakers...might give you some ideas..
https://www.diyaudio.com/community/...eakers-2010-2015yr-model.388989/#post-7089432
Context, my friend.
In any case maybe you could respond to me on those threads so that this one stays on topic?
In any case maybe you could respond to me on those threads so that this one stays on topic?
The tolerance of the capacitors is not relevant in one specific speaker, as an individual cap falls at one specific spot within that +-5%, rather than spanning the whole range in an undetermined fashion. So if you're comparing before and after of the same speaker, say the cap inside is 6.7uF and you add a bypass of .01 it's then 6.71uf.
My advice, having just been thru XO changes on my speakers (two steps forward one step backward), is to only make changes if there is something demonstrably wrong with the speaker OR changing to improved quality parts in the tweeter circuit. If the woofer circuit employs a Zobel network using bipolar caps, the addition of a film bypass cap MAY improve transient response. Each change should be model in SPICE (or similar) followed up with extensive listening. You will need either a crossover schematic OR a parts list & the ability to trace out a schematic from the actual XO etc.
From Martin Colloms review at enjoythemusic.com the 3050 appears to be a well designed speaker!!! Good Luck.
From Martin Colloms review at enjoythemusic.com the 3050 appears to be a well designed speaker!!! Good Luck.
For those interested: I just replaced most components for improved quality parts for my Q acoustics 3050 (not the i version). Sounds much better now IMO. The large mundorf caps were a bit difficult to place, so had to append them to the pcb somehow. It is a very simple crossover design, the 3050i is more complex. Anyway, replaced the resistors and cap, and also added a bypass cap. Parts used:
Original crossover
Cheesy crossover as Danny would say.
Components removed, a lot of glue....
Mundorf FTW, testing can start!
The Supreme Evo is a bit big 🙂However, it fits 👍
Maybe a bit overkill, but it does sound a lot better!
- Mundorf Mcap Supreme EVO Oil 6,8 uF / 800V
- Mundorf MResist classic, 10 Watt 1 Ohm
- Mundorf Silver Gold Oil 0,68 uF / 450V
Original crossover
Cheesy crossover as Danny would say.
Components removed, a lot of glue....
Mundorf FTW, testing can start!
The Supreme Evo is a bit big 🙂However, it fits 👍
Maybe a bit overkill, but it does sound a lot better!
BTW, does anyone know how to remove the styling rings on the front so I can remove the speakers? They did not want to come out easily, I did not want to break or scratch them them (see picture below).
This is the advice from Q Acoustics Support.
"In order to remove the trim you need to use a pallet knife and cloth to protect the cabinet. Slide the blade of the pallet knife between the cabinet and trim, now place the cloth on the cabinet, and then gently lever the pallet knife against the cabinet and the trim should begin to lift, do not try and completely remove at one point, perform in small amounts at different points around the trim until entirely lifted. You should now have access to the four screws that hold the driver in position."
Note that I haven't tried it myself!
"In order to remove the trim you need to use a pallet knife and cloth to protect the cabinet. Slide the blade of the pallet knife between the cabinet and trim, now place the cloth on the cabinet, and then gently lever the pallet knife against the cabinet and the trim should begin to lift, do not try and completely remove at one point, perform in small amounts at different points around the trim until entirely lifted. You should now have access to the four screws that hold the driver in position."
Note that I haven't tried it myself!
Thanks for the help 👍 I also want to add some more damping material in the enclosure. I will gently try this approach, already tried something similar, but it did not move.
No major updates yet, will try to do the lifting of the rings some day. I did replace/enhance the feet with the poor man's version of isoacoustics, see this picture:
I used a piece of wood cut in a round, and then attaching it to the spikes and glue the sound absorber to it. I just placed these, still evaluating but I do think I hear some improvements. I used the PolySound Sylo vibration dampers for this.
I used a piece of wood cut in a round, and then attaching it to the spikes and glue the sound absorber to it. I just placed these, still evaluating but I do think I hear some improvements. I used the PolySound Sylo vibration dampers for this.