Heybrook HB1 Mk1

[scooterkid]

Hi,
I've owned a pair of Mk1 HB1s since new (1984-5 ish). I've re-foamed the bass units due to rot and replaced the tweeters. My last job is to re-cap the crossovers. I attach a couple of pix of the actual crossover and a schematic. Looks very basic. Question are all the plastic box type components capacitors? I ask because the info on cases is very limited. I guess the two in parallel are to give a total value 2.7mF that is not standard. The 4.7 across the LF unit is actually marked 4.7k 100. I assume this is 4.7 mF 100volt wkg.
Can't find good info on HB1 anywhere despite the fact they seem to be well thought of. They are my only speakers!!!

 

[dragonweed]

The tweeter cap is 3.7 uF, not 2.7 (2.2+1.5 parallel connected). Yes all three "plastic boxes" are metallized film type capacitors- probably MKT-s.

 

[system7]

Simplistic sort of crossover with the classic Vifa M21 paper cone. The first order on the tweeter would benefit from impedance correction of the Fs resonance:
High Efficiency Speakers

We have discussed this type of speaker many times:
http://www.diyaudio.com/forums/multi-way/190129-8-1-two-way-diy-speakers-12.html

 

[scooterkid]

Thanks for the replies. Math mistake by me on the addition of the parallel Cs. Do metalised film Cs age?
Fs resonance? What is that?

 

[scooterkid]

Hi
Do metal film capacitors age?

 

[Mooly]

I'm no speaker guru 😀 but FWIW, no film caps don't really age in normal usage. Older caps can suffer from environmental effects (such as moisture ingress) but that's not a problem with the caps in your picture.

Fs I think is the free air resonant frequency of the driver. In other words the natural mechanical frequency it would want to vibrate at when stimulated.

 

[scooterkid]

Hey Mooly,
Thanks for the info re metal film caps.
Cheers

 

[innybiff]

I realise that this is about 18 months too late, sorry, but if anyone is still following then I'd like to pick your brains. I have HB1s which I believe are mk 1and the crossover looks a bit different. The bit I'm wondering about is 2.2 cap. I wonder if anyone can confirm what type it is and whether it's worth replacing. I'll try to attach a pic but I am a bit of a muppet so please bear with.

 

[Mooly]

It looks like a 'metalized polycarbonate film' type. No real reason to swap it.

Like these:
http://www.100y.com.tw/pdf_file/05-Vishay-ERO-MKC1860.pdf

 

[innybiff]

Thanks for the quick reply. I did wonder as it looked quite different from the "plastic boxes" in the OP. I guess there's not much to be gained from changing these. The sound is quite bright, almost harsh but I guess they would be more at home with vinyl than CD.

 

[system7]

innybiff, the thing is that there are many approaches to speakers. Commercial designs often tend to simple crossovers, but TBH, they don't go loud very nicely.

Let's not get too wrapped up in component quality, yours look good enough except for that rather puny 3W resistor on the bass shunt, which must get quite warm.

If I had your speaker, I'd try a better crossover with more bass rolloff to reduce distortion due to cone breakup, and a second order tweeter for the same reasons. This is the hobby. You have nice drivers IMO. The old Vifa M21 is a good bass. The 7.5R and 0.68uF Zobel on the tweeter makes it all amp friendly IMO.

One of my circuits last. Just to show you how it is done. Very low distortion. And nicely flat response.

 

[innybiff]

Hi system7 and thanks for the reply. Once upon a time I studied electronics and understood the theory. Even then I didn't really get practical electronics - circuit design, component selection, etc - but now I don't really remember any of it. I can, though, use a soldering iron to replace one capacitor with another. Anything beyond that and I'd probably be well out of my depth.

 

[TMM]

It looks like a 'metalized polycarbonate film' type. No real reason to swap it.

Like these:
http://www.100y.com.tw/pdf_file/05-Vishay-ERO-MKC1860.pdf

Looks more like a wax paper capacitor to me
https://www.google.com.au/search?q=wax+paper+capacitor

These seem to get a good rep within guitar amplifier circles for their 'tone'. Completely inappropriate for a speaker crossover IMHO and probably needs replacing by now due to high ESR - it's probably over 40 years old already.

 

[georgebrooke]

Crossover Values

innybiff, the thing is that there are many approaches to speakers. Commercial designs often tend to simple crossovers, but TBH, they don't go loud very nicely.

Let's not get too wrapped up in component quality, yours look good enough except for that rather puny 3W resistor on the bass shunt, which must get quite warm.

If I had your speaker, I'd try a better crossover with more bass rolloff to reduce distortion due to cone breakup, and a second order tweeter for the same reasons. This is the hobby. You have nice drivers IMO. The old Vifa M21 is a good bass. The 7.5R and 0.68uF Zobel on the tweeter makes it all amp friendly IMO.

One of my circuits last. Just to show you how it is done. Very low distortion. And nicely flat response.

Hi, I am renovating my HB1 speakers. My crossover is the same as you show, except that the resistor is 15 Ohms, instead of the 18 Ohms shown in the diagram. My HB1 Serial Number is 11053. Can anyone advise as to whether I stay with 15 Ohm or follow the 18 Ohm as given in the diagram?

Thanks for the help

 

[raul_77]

Does anyone know the Wilmslow Audio HB1 kit? How is it compared to the original?

WA HB1 Loudspeaker

 

[georgebrooke]

Crossover

Hi,
I've owned a pair of Mk1 HB1s since new (1984-5 ish). I've re-foamed the bass units due to rot and replaced the tweeters. My last job is to re-cap the crossovers. I attach a couple of pix of the actual crossover and a schematic. Looks very basic. Question are all the plastic box type components capacitors? I ask because the info on cases is very limited. I guess the two in parallel are to give a total value 2.7mF that is not standard. The 4.7 across the LF unit is actually marked 4.7k 100. I assume this is 4.7 mF 100volt wkg.
Can't find good info on HB1 anywhere despite the fact they seem to be well thought of. They are my only speakers!!!

Hi,
I have the same speakers but my crossover has a different value resistor from yours. Did you draw the actual circuit that you have or did you find an HB1 circuit and draw that? I have a 15 Ohm 5W resistor, compared to your 18 Ohm 3 watt. I am wondering if someone has tinkered with my speakers sometime. What is your model number...mine is 11053?
Thanks

 

[trgz]

innybiff, the thing is that there are many approaches to speakers. Commercial designs often tend to simple crossovers, but TBH, they don't go loud very nicely.

Let's not get too wrapped up in component quality, yours look good enough except for that rather puny 3W resistor on the bass shunt, which must get quite warm.

If I had your speaker, I'd try a better crossover with more bass rolloff to reduce distortion due to cone breakup, and a second order tweeter for the same reasons. This is the hobby. You have nice drivers IMO. The old Vifa M21 is a good bass. The 7.5R and 0.68uF Zobel on the tweeter makes it all amp friendly IMO.

One of my circuits last. Just to show you how it is done. Very low distortion. And nicely flat response.

I'm intrigued by your freq runs - two questions if I may: which of the two black lines is the 'Total Amplitude' and which is the 'Energy Frequency Response'? only they look the same colour to me; and which represents the actual audio output to the listener? - thanks

 

[system7]

The top black line is the overall frequency response (Total Amplitude) on-axis, the one just below it is the power response (Energy Frequency Response in Visaton-speak) in the room. Both contribute to what you hear.

That was in Boxsim 1.3, now superceded by the more sophisticated Boxsim 2.0:

https://www.visaton.de/en/literature-software/software

One of the easier simulators to use, and very useful.

 

[AjohnL]

One of my circuits last. Just to show you how it is done. Very low distortion. And nicely flat response.

Any chance of the project file to this please Mr System. I'd like to see how some one who is used to Boxsim sets various things up. Also I have an extreme weakness for the sound of AR-6 speakers and this design may be a good substitute. 😉 Maybe I will need to visit a field of sheep with some hair clippers.

That was in Boxsim 1.3, now superceded by the more sophisticated Boxsim 2.0:

I am getting the hang of using the V2 optimiser but cross over design is still a rather painful experience. Also aiming too high. A better project for me really is something both fairly simple and that results in a useful speaker in the end.

 

[system7]

@AjohnL, I really have forgotten most of this stuff! I am quite happy with my current speakers which are along these Acoustic Research driver lines:

I always thought the simple crossover AR6 was bit harsh. It was a popular choice amongst the rockers at college in the seventies, because Acoustic Suspension (Closed Box) went LOUD without effort.. I prefer a smoother sound.

https://www.stereophile.com/interviews/105villchur/index.html

I do also prefer Boxsim 1.2 to 2.0, because it is better on phase. 90 degree phase aka BW3 is quite easy to get at crossover. It sounds fuller than LR4 IMO.

I uploaded it here:

https://www.diyaudio.com/community/...-from-visaton-free.267787/page-2#post-7126272

I think a proposition BPJ file for this is here:

https://www.diyaudio.com/community/threads/boxsim-v-2-0-launched.331446/#post-6809059

It must be along these lines:

Visaton publish reflex tunings for their drivers onsite. They aren't critical. More a matter of taste.

I have experimented with all sorts of ideas often based on classic KEF and Celestion circuits:

https://www.diyaudio.com/community/...r-audio-r300-bookshelf-speakers.203461/page-2

All good fun. Take you pick! I usually set tweeter level by ear. It is a matter of taste IMO. 🙂