Jump to content

Biamping Questions - Heresy IV


Recommended Posts

Regarding Heresy IV:

  1. When I remove the binding post bridge and connect a stereo amp to the lower two posts, I get sound from the woofer. connecting the amp to the upper posts gives sound from the mid range and tweeter. Does this imply that the internal/passive crossover is being bypassed for the lower pair?
  2. I am testing an active crossover (Ashly RX-1001) for horizontal biamping. The active crossover frequency is set at ~850 Hz. The high/mid output for each channel feeds a class A amp, which is connected to the upper pair of binding posts. The low outputs feed a class D amp, which is connected to the lower pair. I'm managing the gain difference with the Ashly's controls. In this case, is the signal from the class D amp going directly to the woofer and the signal from the class A amp going to the internal/passive crossover and then to the mid range and tweeter?

 

I've seen suggestions that proper bi or tri amping requires bypassing the internal crossover, but I really don't want to mess around inside the speaker cabinet. This project is driven by curiosity, not necessarily the pursuit of better sound. It's a hobby... I do stop messing around and listen to music most of the time. But right now I'm trying to understand what's going on.

  • Like 1
Link to comment
Share on other sites

removing the binding post jumpers just separates the 2 section of the internal x-over so the speaker can be bi amp'd.  each section is still connected, in other words the lower terminals are going through the woofer section still & the uppers are going through the mid/tweets.    

 

im far from an expert on active x-overs but from my understanding to use an active x-over properly you want to bypass the internal passive, otherwise the internal is still in play & will mess with the active's settings. im sure others can chime in & add to this or correct me if what i said is incorrect. 

  • Like 2
Link to comment
Share on other sites

On 1/14/2022 at 10:16 AM, DaveF said:

Regarding Heresy IV:

 

I am testing an active crossover (Ashly RX-1001) for horizontal biamping. The active crossover frequency is set at ~850 Hz. The high/mid output for each channel feeds a class A amp, which is connected to the upper pair of binding posts. The low outputs feed a class D amp, which is connected to the lower pair. I'm managing the gain difference with the Ashly's controls. In this case, is the signal from the class D amp going directly to the woofer and the signal from the class A amp going to the internal/passive crossover and then to the mid range and tweeter?

 

I've seen suggestions that proper bi or tri amping requires bypassing the internal crossover, but I really don't want to mess around inside the speaker cabinet. 

You connected everything properly. No need to mess with the internal crossover. Enjoy your Heresy IV speakers!

Link to comment
Share on other sites

On 1/14/2022 at 6:16 PM, DaveF said:

Regarding Heresy IV:

  1. When I remove the binding post bridge and connect a stereo amp to the lower two posts, I get sound from the woofer. connecting the amp to the upper posts gives sound from the mid range and tweeter. Does this imply that the internal/passive crossover is being bypassed for the lower pair?
  2. I am testing an active crossover (Ashly RX-1001) for horizontal biamping. The active crossover frequency is set at ~850 Hz. The high/mid output for each channel feeds a class A amp, which is connected to the upper pair of binding posts. The low outputs feed a class D amp, which is connected to the lower pair. I'm managing the gain difference with the Ashly's controls. In this case, is the signal from the class D amp going directly to the woofer and the signal from the class A amp going to the internal/passive crossover and then to the mid range and tweeter?

 

I've seen suggestions that proper bi or tri amping requires bypassing the internal crossover, but I really don't want to mess around inside the speaker cabinet. This project is driven by curiosity, not necessarily the pursuit of better sound. It's a hobby... I do stop messing around and listen to music most of the time. But right now I'm trying to understand what's going on.

I have the impression that it can't work like that. When a loudspeaker is actively driven, no passive xover should be in the way. In the case of the Heresy IV, this means that someone would have to run an active crossover with three outputs and three power amplifiers per channel.

Or the tweeter remains passive. Then you only need two active channels for each speaker. In no case should the passive crossover of the bass remain in the way.

 

Please read this before you go on.

One must take into account that the passive crossover of the Heresy IV was designed and developed very long and meticulously. The normal procedure of a manufacturer today is that during the development first the parameters are determined in an anechoic room with a measuring microphone. But here we are already at the finished loudspeaker. Before the manufacturer already knows how the individual components, bass driver midrange horn and tweeter horn behave individually. Efficiency, radiation pattern, phase response and much more. Based on these parameters, the components are selected and together they result in a composition that must be right.

Let's get back to the measurement in an anechoic chamber. The result is the basis for how the active xover is adjusted. Transition points, SPL of each driver, slope, the correction of overshoots and too quiet spots in the frequency band, which Q for which correction and much more.
You need to know all these parameters! if you want to run the new Heresy IV active. But nobody will give you this information. All this effort is made at the manufacturer because it is not about one speaker but maybe about 8000. 
When everything has been carefully determined what it needs in settings so that it is perfectly tuned active then a passive xover is designed with the help of software. The software determines the values of the parts and the circuit as a whole. Then it is built according to these specifications.

 

But that's not all. After the passive xover is built is heard for a long time. It is compared with the active settings, parts of the passive xover are exchanged, different values of resistors, coils capacitors, different interconnections are tried. In the end it is the ears of the engineers and sometimes even panels with test subjects who all exchange their subjective sound impressions with each other.

In the end an optimal setting is found. I hope you realize how much work and knowledge is needed to realize a beautiful result.

All I'm saying is that it's a fallacy to think you can just throw away the passive crossover and replace it with an active crossover without having a clue what you're doing, just the point of bass/tweeter separation. In addition, you have to have an active crossover hardware that controls many parameters at the same time. These are sophisticated devices with many intervention points, Q, slope, shelf and many of them.

To sum it up, either you have access to an anechoic room (alternatively you can do some of the measurements outside), a good measuring microphone and many more things you need, a year of spare time or you will be happy if you accept the Heresy IV as it is, passive, and you buy a high quality amp and you will be happy and enjoy the Heresy as it was designed for you.

 

Link to comment
Share on other sites

The detailed information and feedback is much appreciated.

 

Why does the Heresy IV have two sets of binding posts? If the reason is multi-amping, why not three pairs? If the reason is biamping, it seems the use of the internal crossover network is assumed, with separate external power sources being used - one for the woofer, and the other for the midrange/tweeter combo. Is this worth the effort and expense?

 

We know that the internal crossover network of the Heresy IV splits the signal at ~850 hz. If I'm going to biamp, why not use an external crossover to split the signal at this frequency? Then I wouldn't be sending full range signal to both pairs of binding posts. 20-850 hz from one amp, 850 and above from the other. Perhaps this is simply a waste of time.

 

Not using both pairs of posts makes me feel like I'm leaving something unused, something that might improve... something. 

 

BTW, my biamp setup worked fine, but either the Ashly crossover or the Fosi class D amp created occasional loud tones in one channel, so I'm dropping back to one amp (Schiit Aegir), which sounded great all along. I may try a Minidsp 2x4 HD /mic/REW combo to EQ the sound (because I can't seem to leave well enough alone.)

 

 

Link to comment
Share on other sites

I've slapped a Heresy atop the Jubilee bass bin before and "actively biamped".  Worked totally fine.

 

Took my (already existing biamp lines) and attached one to the Heresy, the other to the Jubilee bass bin.  I think (been long time) I fed full signal to the Heresy .....  I may have truncated it where the Jubilee bass bin kicks in.

 

but the reality when I did it was, the active split the signal into a bass signal which went to the bass bin.  The other half of the signal want to the 3-way Heresy and I simply allowed the passive in there to do its work, which it did fine.

 

It might not be a perfect situation as the perfect situation might call for active TRI-amping verses biamping.....  I think even in their cinema line, don't they have the K510 sitting on top of the K402 with a small crossover there for the two of them yet, the speaker itself is biamped?

 

 

DSCN2930.JPG

  • Like 1
Link to comment
Share on other sites

3 hours ago, DaveF said:

The detailed information and feedback is much appreciated.

 

Why does the Heresy IV have two sets of binding posts? If the reason is multi-amping, why not three pairs? If the reason is biamping, it seems the use of the internal crossover network is assumed, with separate external power sources being used - one for the woofer, and the other for the midrange/tweeter combo. Is this worth the effort and expense?

 

We know that the internal crossover network of the Heresy IV splits the signal at ~850 hz. If I'm going to biamp, why not use an external crossover to split the signal at this frequency? Then I wouldn't be sending full range signal to both pairs of binding posts. 20-850 hz from one amp, 850 and above from the other. Perhaps this is simply a waste of time.

 

Not using both pairs of posts makes me feel like I'm leaving something unused, something that might improve... something. 

 

BTW, my biamp setup worked fine, but either the Ashly crossover or the Fosi class D amp created occasional loud tones in one channel, so I'm dropping back to one amp (Schiit Aegir), which sounded great all along. I may try a Minidsp 2x4 HD /mic/REW combo to EQ the sound (because I can't seem to leave well enough alone.)

 

 

The configuration of your Heresy IV allows bi-amping. This is the mode WITHOUT active crossover but with two stereo amplifiers, one feeding the two bass inputs, the other the two tweeter inputs.

In your Heresy IV the passive crossover is ALWAYS in the signal path, no matter if you use one or two stereo amplifiers.

Therefore, it is completely unnecessary to use an active crossover before the two stereo amplifiers. A crossover always adds errors. If you use an active crossover and also a passive crossover then the errors of both crossovers add up to even bigger errors.

There is only one reason to use an active crossover in addition to a passive crossover, the use of a tube amp exclusively for the tweeter. This way the tube amp does not break down because it does not transmit bass.
But it is not an elegant solution. Even if the active crossover has only the job of separation and otherwise the signal is not changed in sound or phase, you would have an addition of slope. It is not a smart solution and results in unlinear distortion. Therefore a tube amp is not the right choice for passive biamping at all.

 

If you really wanted active control, then the passive crossover in the Heresy must be removed. For that you have to unscrew the speaker.

If you use only two amps and not three amps to go Active then ONLY THE PART of the passive crossover that separates the frequencies between the midrange and tweeter must still be used.

But the part of the high pass crossover that separates the midrange from the bass and addresses the low cut of the midrange must also be removed.

That's what Coytee means. There is the Jubilee cinema 3 way system, there is the tweeter horn of the K510 in addition. This system gets no third active path and no third amp but between K402 and K510 it is passively separated. In sum both, the K402 and the K510 are one tweeter which „sees“ the active treble part of the amplification as one whole signal for both of them together.

The example where Coytee connects a whole Heresy box including bass to his actively separated tweeter section of his Jubilee is misleading for your question. Sure, there's some sound coming out, but it's not technically correct, it's just a fun way to soundproof a party. Coytee?🤓

Link to comment
Share on other sites

@KT88, thanks for the reply. Your points regarding an active crossover are valid. I'm glad I only paid $75 for the Ashly (anyone want to buy a nice pro audio crossover?)

 

There is still the matter of gain matching if the two amps are not identical, and incorporating a sub will require additional work. If I understand your basic point, I don't want to introduce any external filters.

Link to comment
Share on other sites

Dave, the safest and easiest thing would really be if your preamp feeds two identical amplifiers for passive biamping. If they are different types of amps you need to know if their input sensitivity is the same and if the gain factor is identical.
If not then it will not work well. It might work if the power amps or one of them has a volume pot on the input but only regarding the sensitivity. But this will degrade the signal and it is also only a rough estimate of the ears if bass and mid/high section are exactly loud enough to each other.

Here gain and sensitivity are discussed a bit.

https://www.diyaudio.com/community/threads/understanding-input-sensitivity-gain-output-power.359586/

 

If you want a sub in addition you need a pre out signal which is volume pot controlled like the two stereo amps are also. The sub normally has a volume pot to adjust it to the other components. But the Heresy goes nicely deep (as I have learned, I do not have one) So the sub should only add the very low frequencies because the sound will be better from the main speaker in the region where it works itself.

Link to comment
Share on other sites

On 1/14/2022 at 12:16 PM, DaveF said:

Regarding Heresy IV:

  1. When I remove the binding post bridge and connect a stereo amp to the lower two posts, I get sound from the woofer. connecting the amp to the upper posts gives sound from the mid range and tweeter. Does this imply that the internal/passive crossover is being bypassed for the lower pair?
  2. I am testing an active crossover (Ashly RX-1001) for horizontal biamping. The active crossover frequency is set at ~850 Hz. The high/mid output for each channel feeds a class A amp, which is connected to the upper pair of binding posts. The low outputs feed a class D amp, which is connected to the lower pair. I'm managing the gain difference with the Ashly's controls. In this case, is the signal from the class D amp going directly to the woofer and the signal from the class A amp going to the internal/passive crossover and then to the mid range and tweeter?

 

I've seen suggestions that proper bi or tri amping requires bypassing the internal crossover, but I really don't want to mess around inside the speaker cabinet. This project is driven by curiosity, not necessarily the pursuit of better sound. It's a hobby... I do stop messing around and listen to music most of the time. But right now I'm trying to understand what's going on.

 

Heresy IVs are configured for bi-WIRING, not bi-amping.  That means 2 pair of wires from one amp channel to each speaker.  A dubious benefit if your wires are large enough. 

 

Bi-amping, actually for a Heresy, tri-amping, should bypass any passive x-over should be bypassed (short of a capacitor protecting  the horn drivers) and then the electronic crossover can contour the driver's response, minimize the overlap between drivers and time align the drivers. This has a verifiable benefit.

  • Like 1
Link to comment
Share on other sites

Here is another way to separate the high drivers from the low drivers,

if you have a tube amp with multiple taps on the output transformer...

 

These methods present the high and low drivers with different voltages

from the same amp through the different taps of the output transformer.

 

Multiple configurations are presented to get different relative attenuation.

 

"Bi-tranny tapping"

 

 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...