Using different HF units with coaxial drivers

[Nuuk]

I'm trying some B&C DE 250-8 and DE 500-8 HF units with my Hawthorne Audio Sterling coaxials.

I notice that while the standard HF unit supplied with the Sterlings (ASD1001?) is repelled by the woofer magnet, the B&C units are attracted. Does this have any affect on the operation of either the HF unit, or the woofers?

 

[Nuuk]

Aren't thereany speaker experts on this forum?

 

[chris661]

The two magnets attracting/repelling probably won't have much effect, but if you want to be sure, put some metal on one of the magnets (the part that faces the other magnet), so it works like shielding. Blutack in place (stops vibration) and give it a go.

 

[Nuuk]

Thanks Chris. The DE 500-8's require an aluminium adaptor plate that is bolted to them, and is therefore between them and the woofer magnet.

I asked because I remember using the Ciare 250 with additional magnet and it was supposed to make a difference how the additional magnet was mounted on the Ciare.

 

[infinia]

I notice that while the standard HF unit supplied with the Sterlings (ASD1001?) is repelled by the woofer magnet, the B&C units are attracted. Does this have any affect on the operation of either the HF unit, or the woofers?

The repelling action forces a little more flux into the woofer VC gap so empiracally you get maybe up to 1 dB more sensitivity. Not sure about HF unit but expect similar effects.

 

[Nuuk]

Thanks Infinia. I guess as ever, the proof of the pudding is in the eating!

I'll move on and and see if I can integrate the new HF units with the HA woofer.

 

[Nuuk]

According to B&C, joining the HF unit to the woofer does affect the T&S parameters of both units and you therefore need to measure the units again when they are joined together!

 

[Brett]

According to B&C, joining the HF unit to the woofer does affect the T&S parameters of both units and you therefore need to measure the units again when they are joined together!

Of course you should measure, then you'll know, but I doubt it's going to be much. On the Scanspeak pages they sell second magnets of the same size for bucking purposes of older drivers that don't have them. The difference calcs out to be ~0.25dB as the second magnet is outside the magnetic circuit and will have little effect.

The attraction/repulsion is most likely due to the magnets being charged in opposite polarity from the factory for whatever reason.

 

[Nuuk]

When I listen using the existing crossover, it isn't so much the frequency response that is amiss, it's the timing - it's way off!

 

[Brett]

When I listen using the existing crossover, it isn't so much the frequency response that is amiss, it's the timing - it's way off!

What do you mean? A physical offset time delay between them?

 

[Nuuk]

No, it's as if the music is being played out of time. The pace is gone, it's plodding along and sounding very 'mechanical' instead of 'organic'.

 

[Brett]

No, it's as if the music is being played out of time. The pace is gone, it's plodding along and sounding very 'mechanical' instead of 'organic'.

I have no idea what that means.

 

[tinitus]

Sounds much like you need some BSC

Also try to reverse polarity on tweeter

Could we see a picture/scematic of xo

 

[Nuuk]

I have no idea what that means.

Well understanding often goes with experience and if you haven't experienced something it is hard to describe it.

Sounds much like you need some BSC

Well the frequency response sounds OK to me, it's the 'timing ' issue that I am trying to understand.

Also try to reverse polarity on tweeter

Done that. It does make an audible difference but not to the 'timing'.

Could we see a picture/scematic of xo

I don't see why not as it is published on the HA forum. I have increased the 5R6 resistors to around 8 ohms to compensate for the extra sensitivity of the DE 500-8's over the ASD1001's.

 

[Brett]

Well understanding often goes with experience and if you haven't experienced something it is hard to describe it.

I own/have owned lots of coaxes, but have never heard one sound 'mechanical' or 'non-organic'. Have you measured both drivers?

 

[Nuuk]

I own/have owned lots of coaxes, but have never heard one sound 'mechanical' or 'non-organic'. Have you measured both drivers?

No I don't have measuring equipment.

Do you recall if all your coaxial drivers/HF drivers had the same magnetic field 'orientation', ie, did they all attract one another or repel one another?

 

[Brett]

No I don't have measuring equipment.

Well you are at a huge disadvantage if you ever want the system to work well.

Do you recall if all your coaxial drivers/HF drivers had the same magnetic field 'orientation', ie, did they all attract one another or repel one another?

No because they were typically bought as a complete unit.

The magnetic polarity isn't going to be an issue. Not knowing how they measure and being able to integrate them properly is a much, much larger one.

 

[Nuuk]

The magnetic polarity isn't going to be an issue. Not knowing how they measure and being able to integrate them properly is a much, much larger one.

Yes, I realise that.