The New Hypex Fusion Plate amps

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Yes I was not clear. Lower qts = more eq. Perhaps I'm mistaken but I thought you'd need some reasonable watts to driver the L26RO4Y woofer to reasonable SPL and Xmax given it is around 86dB?

You would need a significant amount of power IF you were trying to maintain Xmax as you went up in frequency. In these dipole applications though, you're not.
Drive voltage drops at a significant rate with increasing frequency owing to the dipole correction, low-shelving Q equalization and low-pass filter associated with the woofer/mid crossover.
Generally, power amplifiers with nominal ratings in the 50 watt range will be just fine.

FYI, the L26RO4Y driver requires a shelving Q-correction of about +10db centered at 35Hz to achieve an effective Qts = 0.5.

Dave.
 
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Drive voltage drops at a significant rate with increasing frequency owing to the dipole correction

Perhaps it might be better to take this discussion in another thread or PM as to not wanting to clutter this thread with off topic. Please feel free to drop me a private message to sort this out as my understanding of amplifier power is different.

It is my understanding due to dipole cancellation you'll need EQ to bring the low frequencies (for example 35hz) up to the same SPL as the midrange and tweeter. I have a small baffle and require at least 16dB eq to bring the lower frequencies up. 16dB eats a lot into the 100watt budget.
 
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For open-baffle setups it requires X amount of power to push Driver-X to Xmax, at a particular frequency.....whether you're using EQ or not.
In other words, the power requirement is completely independent of any EQ (dipole, Q-correction, whatever) requirement.

Don't think of it in terms of matching sensitivity to a midrange or tweeter. That's irrelevant.

Does that make sense??

Feel free to PM if you like.

Dave.
 
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Hi All,
After a bit of back and forth with Dave, I did a little experiment to verify his words. I ended up using at best 50 Watts according to the oscilloscope and that was loud. I don't think I could push it more so..........

For OB I'm only using at best 50 Watts into a relatively generous xmax woofer. Sealed is not OB so I apologise in saying larger wattage is ok for me as it seems I not really using the wattage for the OB application. If I was then hearing damage would probably occur.

Thanks for your patience Dave.
 
Don't forget the amplifier limitations are Max voltage and Max current besides power (wattage) as such. As woofer's impedance around resonance is usually few times above nominal 4-8Ohm, it may take same voltage to reach <50W as it does to reach 200+W into nominal load..

Good point. The 123 could run out of steam quickly in these conditions. If I buy the Fusion I will go for the 253... (leaves also some more options with other drivers I may use in the future)... thanks for all the responses... ;)

By the way, is anyone using the remote control solution of Hypex for Fusion? Does it work ok? Is the volume persistent after repower, or can you only have a pre-configured default volume at power on? Do you get good audio quality (e.g. clarity) still at low volume, while using digital in?

Fedde
 
If you do not mind, I have a few more questions regarding the USB connection:
1. When you upload new filters do you need both Fusions connected via USB? Or is the slave always synchronized via the S/P-DIF link?
2. Is the uploading of filters fast?
3. Can you keep USB connected to the PC or does it affect the sound quality?

Fedde
 
If you do not mind, I have a few more questions regarding the USB connection:
1. When you upload new filters do you need both Fusions connected via USB? Or is the slave always synchronized via the S/P-DIF link?

You have to upload each plate on by one via USB
2. Is the uploading of filters fast?

Yes
3. Can you keep USB connected to the PC or does it affect the sound quality?

It doesn't

Fedde
 
I have been following the thread and I did see where you can get to the amp inputs directly but I had one more question about that...

On the 3 channel version can you leave 2 as is and add hardware in the loop to the third?

I still use Mr.Eraths' feedback units on the woofers but would really like the simplicity of the dsp and 3 amp channels in one unit.
 
I just bought a pair of Fusion 253's for my ChilL baffles... I look forward to try them out!!! :)

In the meantime, I need to prepare enclosures. Does anyone has some good advice on this? I understood that some people make them from MDF. Can I put panels directly down from the screws or do I need to reserve more space around the PCBs. How deep do I need to make the enclosure?

Another question, is somebody using the soft clipper. Does it have audible effects at low or normal sound levels?

Fedde
 
Running 192K at long distances are always a problem and why run at 192K when this is downsampled in the Fusion to 96K ( 93,75k to precise).

Do you know why 93,75k was chosen (apart from that it appears to be used in Kii3 and LS1, jitter impact?)? The DAC can run at 768 kHz and the SRC to 216 kHz. Choosing a higher frequency would provide better support for 192 kHz material (though you can doubt how audible this is) and probably more biquad precision (more relevant). There must be suitable frequency up in the 1xx range.

Fedde
 
Do you know why 93,75k was chosen (apart from that it appears to be used in Kii3 and LS1, jitter impact?)? The DAC can run at 768 kHz and the SRC to 216 kHz. Choosing a higher frequency would provide better support for 192 kHz material (though you can doubt how audible this is) and probably more biquad precision (more relevant).


Assuming the number of biquads is limited by processor power, going to 187.5 kHz or whatsoever would halve the number of biquads you can do.
 
Assuming the number of biquads is limited by processor power, going to 187.5 kHz or whatsoever would halve the number of biquads you can do.

That is not the reason. According to the data sheet the DSP can do 1500 double precision biquads at 48 kHz...

Unless Hypex wants to reserve room for future FIR possibilities... :p (6000 taps possible at 96k, less with biquads at the same time)

Fedde
 
Don't forget all functionality eats resource even not used. Delay for example, if you reserve 500mS and not use as end user, it's not available anymore for other tasks. It all ads up very quickly!!!!!

Something about Fir:

Filtering a minimum phase device can be done perfectly with minimum phase filters ( IIR). Fir comes in handy when you want to equalize the phase of a total system and must be done in the input path. You can try this simply with a convolution engine ( hardware, software and Rephase) in front of the Fusion and test if there is an improvement.
 
Don't forget all functionality eats resource even not used. Delay for example, if you reserve 500mS and not use as end user, it's not available anymore for other tasks. It all ads up very quickly!!!!!

Something about Fir:

Filtering a minimum phase device can be done perfectly with minimum phase filters ( IIR). Fir comes in handy when you want to equalize the phase of a total system and must be done in the input path. You can try this simply with a convolution engine ( hardware, software and Rephase) in front of the Fusion and test if there is an improvement.

Implementing delay especially costs memory space (and bandwidth), not so much resources (just some shifted copies).

I was thinking in the same lines regarding FIR, I could do FIR phase corrections on PC side before the audio data is transmitted via S/P-DIF to Fusion. But this is just the icing on the cake, I first need to get the basics of the IIR EQ/cross-overs right...

@DS23man: do you have any advice on the mounting the plate amps in MDF? Can I make this tight around the PCBs or do I need to reserve some room (e.g. a few cm below the PCBs or is it required even around the PCBs)?

Fedde
 
Implementing delay especially costs memory space (and bandwidth), not so much resources (just some shifted copies).

Correct, but Fir needs memory

I was thinking in the same lines regarding FIR, I could do FIR phase corrections on PC side before the audio data is transmitted via S/P-DIF to Fusion. But this is just the icing on the cake, I first need to get the basics of the IIR EQ/cross-overs right...

@DS23man: do you have any advice on the mounting the plate amps in MDF? Can I make this tight around the PCBs or do I need to reserve some room (e.g. a few cm below the PCBs or is it required even around the PCBs)?

Fedde

Don't make it to small because you need some room for connectors and cables.