How to HFD five Hypex FA502 plate amp (for active subwoofer only)

[kalbi]

As FA502 not available yet therefore I didn't ask Hypex.

I am planning to replace plate amps for five active subs:

1. Sub A - one pairs of 2x10" driver, sealed, to handle 40Hz to 120Hz, fourth order
2. Sub B - three units of 4x12" driver, sealed and isobaric design, 40Hz and below, fourth order
3. Analogue output from pre-amp
4. Gain of power amp - 26.5db

Sub config:
Left channel - Sub A -> Sub B
Right channel - Sub A -> 2x Sub B (stacked)

Tools:
I've ordered Dayton mic and Focusrite Scarlett Solo, and installed 4.62 HFD.

I've read HDF maunal, and had questions below:

1. Butterworth vs. Bessel, which is best for my application?

2. The manual said that remote link is option between left and right channel for analogue daisy chain, then how to measure and correct low frequency for both left and right channel via USB. This is because only one plate amp connected via sound card.

3. I'll be grateful if someone could provide a data file (assuming a flat response, 120Hz and below) to upload to the 4.62 HDF as a reference, and I'll modify from there?

4. What other factors should I consider and info should I provide?

Thank you for reading and suggestions!

[MarcelvdG]

What does HFD stand for? A free online dictionary lists 25 meanings (from Honolulu Fire Department to House of Flying Daggers), but none seem applicable.

https://acronyms.thefreedictionary.com/HFD

[toetertje]

Hfd staat voor Hypex filter designer.

[MarcelvdG]

OK, then here is my take on the first question. I have never used anything from Hypex, so I can only answer generic questions that are not specific to Hypex.

1. I'd go for Butterworth. Unless the differences between the path lengths from the mid/high loudspeakers and the subwoofers to your ears are much smaller than the wavelength at the crossover frequency, the system will have a poor phase response around cross-over anyway, so I don't see the advantage of using Bessel. Besides, only low-pass Bessel filters have a very good phase response, Bessel high-pass filters have not.

2. to 4. No idea.

[ds23man]

Why this strange sub construction?

[Leeuwarden]

Waarom in het Engels?

[pappaleo]

Waarom in het Engels?

Why.

[Ah!buis]

Waarom in het Engels?

Ohw, is 't Engels
Dat was me nog helemaal niet opgevallen
Anne

[Leeuwarden]

Ja precies.

[ds23man]

Ja precies.

Ja krekt...

[kalbi]

OK, then here is my take on the first question. I have never used anything from Hypex, so I can only answer generic questions that are not specific to Hypex.

1. I'd go for Butterworth. Unless the differences between the path lengths from the mid/high loudspeakers and the subwoofers to your ears are much smaller than the wavelength at the crossover frequency, the system will have a poor phase response around cross-over anyway, so I don't see the advantage of using Bessel. Besides, only low-pass Bessel filters have a very good phase response, Bessel high-pass filters have not.

2. to 4. No idea.

Thanks for the recommendation! Good to know where should I begin with!

I'm using a bookshelf limited low speakers, and integrated the subs in add-on mode.

[kalbi]

Why this strange sub construction?

I am looking at upgrading my existing system with minimum costs, and fusion plate amp allow me to directly digital the subs after I've familiarised with how analogue works.

The Hypex HFD provide a mean for me to configure, measure and monitor individual subs on a single platform, and sum them all.

[ds23man]

With crossover points this close you will never get it right or you must use 48db/oct filtering minimum.

[Henkjan]

maybe this software can be helpfull:
http://andyc.diy-audio-engineering.org/ ... index.html

[kalbi]

maybe this software can be helpfull:
http://andyc.diy-audio-engineering.org/ ... index.html

Thanks! This provide a good read, and another alternative to multiple subs config. What I'm thinking of is to add-on to one another, i.e. Sub A add-on to the limited full range, and Sub B add-on to Sub A. I don't have any experiences, not sure will it works.

[kalbi]

With crossover points this close you will never get it right or you must use 48db/oct filtering minimum.

Do you mean the xover point between the two subs?

1. Sub A - one pairs of 2x10" drivers, sealed, to handle 40Hz to 120Hz, fourth order
2. Sub B - three units of 4x12" drivers, sealed and isobaric design, 40Hz and below, fourth order

I've made a mistake here, should be 30Hz or below. Why 30Hz and below? I'd done a measurement for Sub B more than a decade ago. Strangely that the sub only done well between 20Hz, I suspect that the plate amp wasn't powerful enough to move the 4x12" drivers.

The above configuration was just a starting point to embark, and figuring out best setting from there.

Moreover, all the settings on plate amps were analogue and for rough estimation only, very frustrating. Unlike the HFD, one can configure settings down to decimal point.

[kalbi]

Time to close the loop.

I am very pleased with the purchase. And easy to setup too! At least for my usage.

As my main speakers is LR 4th order therefore it made thing easier.

I would see the set up as a three ways, i.e. full range, upper sub and lower sub.

All lowpass and highpass were LR 4th order, the only concern was matching the volume of the three ways. Done and happy.

[ds23man]

[kalbi]

I was lazy to pull out the gear for measurement. However, I listened to sweep from 20Hz to 300Hz, very pleased with the result!

The lowpass for the upper sub were between 80Hz and 120Hz, three presets. Highpass at 45Hz.

The lowpass for the lower sub was 45Hz too! One preset inverted, for comparison purpose.

Had set delay to the two subs closer to the listening position.

All LR 4th order, so phase wasn't an issue.

Unable to upload pictures. Is 2.8MB too big?

[ds23man]

Max 1MB.

[kalbi]

Thanks! Will resize.

[kalbi]

[kalbi]

Can someone tell me what does the capacitor and resister (???) Between the two drivers?

How does it affect or improve the sounds?

TIA

[kalbi]

It's to block high frequency.

In my application, can neglect it.