STOP PRESS ..... Bombshell

[macaroonie]

Nelson Pass now has 4343's and is coming round to active .
I met him once in Sacramento , lovely man.
He's very positive re GT.

I always liked his amps.

[Ian Mackenzie]

Here is the video interview and its quite interesting.

https://www.youtube.com/watch?v=zgWJuBjKdIo&feature=youtu.be

Nelson Pass is a fascinating guy and really clever.

If you view the video and are wondering who the acquaintance in Australia Nelson Pass refers to that's me.

The advanced pre launch PR is nice to have.

I will be rolling out more about the product soon with more videos.

Ian

[grumpy]

Interesting interview, amp design philosophies, and industry cross-path/relationship stories.
Nelson's never boring :)

Looking forward to the upcoming crossover implementation/collaboration... that was quite a circuit board!!

Best regards and success,

-dave

[Ian Mackenzie]

Hi Grumpy,

That young guy can be my PR man...

I am hoping it won't be far off now. There is quite a product story behind this and I hope to put up some aspects of that in an interview format.

On the board its grown to 16.75" wide by 13.25" deep since the last revision.

Its quite a piece of work and is the culmination of lots of discussions, market feedback, international travel, listening in peoples homes and hundreds of emails over the past 3 years.

Some insights for you.

Commercial crossovers are more or less cost driven cookie cutter products and the user has to figure out the rest.

I have gone about it differently in that the product delivers key performance outcomes with exotic analogue circuits in a number of key areas. The product is also scaleable from a simple plug it in make it go situation to catering for the thinking cap type of customer who wants to make adjustments, tweaks and evolve a system over time.

Working out how bring the concept to a design, build and then manufacture has been a significant exercise.

The board can be configured by the factory or the user in a number of ways such as a traditional stereo 3 way tri amp situation, stereo bi amp situation, stereo bi amp situation with sub woofer and special tri amp configurations like the Everest DD67000. In the context of these configurations the user can specify a particular model loudspeaker for bi amp operation and a set of plug in daughter boards are provided which are set up for that specific system. If the customer wishes to make a system fully active that can configured with daughter boards for customised equalisation of low, mid and high frequency drivers. This is all in a single stereo chassis.

A bi amp stereo product is also in the works which will have many of the above concepts. Just a bit less of everything which l should point out is still a lot.

I am happy to answer questions.

If the Mods want move this thread to a more appropriate forum please do.

[Chas]

Hey Ian, any plan to have balanced I/O and slopes/freq. correct for biamping 4345’s? If so, I’m a potential customer!

[toddalin]

A really nice guy. At one time (Sept. 2016) I presented my 075/2402 lenses to him and he was very impressed and wished me luck in the endevor. He also asked if I could/would make them in larger sizes.

[Ian Mackenzie]

Hey Ian, any plan to have balanced I/O and slopes/freq. correct for biamping 4345’s? If so, I’m a potential customer!

Hi Chas,

The board l was referring to does balanced and unbalanced in/out.

On the 4345 yes. The crossover requirements of 4345/4343/4350 and clones with the 2123H will be available. Also the other bi amp monitors and consumer models. Those crossover requirements will also be available in the stereo two way product.

[macaroonie]

This is pretty exciting Ian , you are a dark horse.
Best of luck with your project.
NP is a dude , you are in good company.

M

[Cyclotronguy]

We're Ian Mac in a bubble he'd be a dark horse.
But I have it on good authority that he's had some pretty learned assistance on this project
I think this is going to be very very special!

[BMWCCA]

Were Ian Mac in a bubble he'd be a dark horse. Fixed it for you!

[DavidF]

"...Working out how bring the concept to a design, build and then manufacture has been a significant exercise. …"

I have to think this a modest understatement! Exciting endeavor none the less.

[Chas]

Hi Chas,

The board l was referring to does balanced and unbalanced in/out.

On the 4345 yes. The crossover requirements of 4345/4343/4350 and clones with the 2123H will be available. Also the other bi amp monitors and consumer models. Those crossover requirements will also be available in the stereo two way product.

Very cool, can’t wait to hear more. :lurk:

[Champster]

That was a great interview and what a nice guy to make himself available for such an in depth interview.

Hi Ian,
Are you considering an active crossover for the M2/SUB18s? It seems to me that if there were an option for less technically capable audiophiles, JBL would sell a lot more of these speakers to home listeners. Not only would it allow us to step away from fan based amps, it would eliminate the huge learning curve of Audio Architect.

From your reply to Grumpy above, it appears you’re heading down the analog path and as such, would they have fixed crossover points/slopes/etc parameters making for a great plug and play product?

Thanks
Paul

[Ian Mackenzie]

Hi Paul,

You are correct. The learning curve is a barrier to obtaining optimal results using an active crossover.

I discussed this with Greg Timbers early on in the development of the product. Greg said a plug in card set up for a specific system was much easier way to go for consumer users.

I talked this through with Nelson Pass and we worked towards the concept of plug in active crossover cards. The cards can be set up in a number of ways to create the desired crossover configuration using a unique motherboard. The genius of Nelson Pass at work here.

We will certainly take on board your request for a M2 / Sub crossover configuration. I have put this in the to do bucket for investigation.

The objective is to provide factory set up active crossover cards for specific systems. A range of adjustable cards will be made available for audio amateurs who wish to develop their own systems.

I will host insight webinars for owners of the product and Facebook groups where users can share their experiences and learnings.

[Robh3606]

The objective is to provide factory set up active crossover cards for specific systems. A range of adjustable cards will be made available for audio amateurs who wish to develop their own systems.


Hello Ian

How are you going to handle CD compensation on horns?? Typical canned CD curves in crossovers are usually a compromise at best. Are you going to have provisions so there are more than one curve and would the curves be adjustable??

Rob:)

[Ian Mackenzie]

Hi Rob,

Great question.

We can provide more than one pre set curve or full adjustment for the user.

There is latitude for multiple EQ points.

Some users will bi amp in the conventional sense and use the existing JBL Horn passive EQ or that pertaining to any loudspeaker system.

The thinking cap customer as Nelson Pass refers to may wish to make the system fully active and we can provide EQ modules for that.

We are still working though some of these things and appreciate your questions.

Ian

[Wayner]

+1 for applying this to the M2.

[Ian Mackenzie]

An update.

In view of the current circumstances this is going to take a bit longer than expected to get to market so bare with us.

Some progress. l just signed off on the industrial design by one of the leading designers in the industry Desmond Harrington.

https://m.youtube.com/watch?v=i571p0xdbho

l will be looking to arrange some prototype evaluations in the field. When l to get to that point l will ask for a show of hands.

[brutal]

Here is the video interview and its quite interesting.

https://www.youtube.com/watch?v=zgWJuBjKdIo&feature=youtu.be

Nelson Pass is a fascinating guy and really clever.

If you view the video and are wondering who the acquaintance in Australia Nelson Pass refers to that's me.

The advanced pre launch PR is nice to have.

I will be rolling out more about the product soon with more videos.

Ian

I watched the whole thing and saw the quick show of that mainboard!

I especially liked it when Nelson Pass proclaimed to have an extensive Frank Zappa collection!

[Ian Mackenzie]

As l am sure you all appreciate COVID 19 is going to be around for a while and unfortunately this has impacted on plans to get product to market on a number of levels.

However, l thought l would put it out there that this would be a good time to conduct some user evaluations with prototype product while people are at home.

We have previously completed some user evaluations and are at a 3rd prototype revision. Nelson Pass and l have spent many many hours on refining the product towards the current modular design concept and at this point we would like to see some product feedback from out in the field.

I have some prototype product set up for the JBL Everest DD65000, DD66000, DD67000 systems in either bi amp or triamp mode.

Therefore if any LHS members with the Everest’s would be interested in being engaged in a product evaluation or if you have a close friend with the Everest’s who is interested please contact me via a PM. l will then discuss the evaluation process in detail with you and work it out from there. This applies to LHS members in mainland USA, South America, Mexico, Canada, Europe, Asia and the UK.

Other jbl system evaluations will be investigated.

I will post some images of the prototypes in the next couple of days.

[Robh3606]

Hello Ian

Glad to see things going forward! Best of luck!

Rob:)

[Ian Mackenzie]

Hi All,

I thought l would let you know where this is at.

With the flux of time during Covid 19 there has been some pondering of matching needs to product features and benefits.

With that in mind l am interested in your impressions and thoughts on the following:

Option 1.
A simple to use stereo 2 way universal analogue active crossover with continuously adjustable crossover points from 200-1500 hertz or similar.

24 dB LR slopes, state variable with balanced/unbalanced inputs and outputs.
Designed with premium TI audiophile chips and hi quality Wima capacitors and high quality pots.

This will be an improved Ashly or other universal crossovers like the Rane.

The idea is too keep it simple for those who want premium sound quality but aren’t into taking the lid off and making fine adjustments.

It won’t cost an arm and a leg because you will deal direct with the factory.

Option 2.
A stereo 2 way analogue active crossover that can be set up for specific Jbl systems using plug in cards.
In concept like the DX1. It will also feature a sub out put with an optimal low pass filter.

The crossover frequency, slopes ect are all set precisely for your particular Jbl systems.

The design will use premium class A Jfet buffers and high headroom studio quality discrete op amps.
Available in unbalanced as this crossover is for consumer hifi fanatics. Balanced connection and circuits add cost and complexity and frankly don’t promise improvement in sound quality.
All parts are of the highest quality. This product will be endorsed by Greg Timbers.

Option 3.

A Stereo 2 way or Tri amp analogue active crossover for the audio amateurs who enjoy building project loudspeakers of their own design.

The design will feature premium class A buffers like option two but with adjustable plug in crossover cards for crossover points and slopes. Special purpose plug in cards will be made available for equalisation of low and high frequency drivers and phase alignment of low and mid frequency drivers.

It will available with unbalanced or balanced connectors to a customers requirements.

Option 3 will be sold with the Dayton Omni Loudspeaker measurement system.

I have a reasonable inventory of popular JBL small and large format compression drivers and a growing collection of horns and woofers. So I can offer users with ball park crossover set up guidance.

Why Analogue? Because it’s simple with not a lot to learn and adjust. The focus is on doing the least damage to your precious analogue source. Vinyl is well and truly back and it sounds incredible with with a pristine signal path.

I have some state of art test abs measurement equipment on order.

Just a show of hands would be useful or other ideas.

Ian

[BMWCCA]

Thanks for the update.

I could be in for either option #1 or #2, price dependent, for the 4345 Clones. I'm currently still using the Ashly XR1001 with a spare for backup.

[Ian Mackenzie]

Thanks.

It’s too early to call out pricing.

In a conventional distribution chain you have an importer/wholesalers and then a retailer. This creates several markups.

Active crossovers are a specialised component and not something normally stocked by a hifi shop. Invariably the user needs after sales support so a direct factory relationship an option.

[DavidF]

A hybrid of Option 2 & 3 would be more of interest to me. A unit configured as with Option 1 would compete as just another Ashley or Rane competitor, albeit with much better component parts. May be more cost-acceptable than Option 2 or 3 but there may be just too many alternatives out there to differentiate this configuration.

Keeping the product tied to specific JBL designs may be OK but I think it would limit reach into the market. Having the option to customize Option 2 to other configurations would make it more appealing. Obviously a more hands-on than Option #1 but far more usable to the typical sound-oriented or DIY-oriented user.

[Ian Mackenzie]

Thank you for your feedback.

[Ian Mackenzie]

One thing to appreciate is that at least on this site a number of users have adopted either the Rane or the Ashly crossovers.

I am not sure if that is a user choice or a price decision?

Only a few have adopted a switchable crossover such at the Bryston 10B or the FirstWatt F4.
Neither are pre set or programmed for a pre described loudspeaker with bi amp capability as intended by the loudspeaker designer
These are priced above US$1500.

There have been a number of enquiries or the discontinued DX1.

[Ian Mackenzie]

A hybrid of Option 2 & 3 would be more of interest to me. A unit configured as with Option 1 would compete as just another Ashley or Rane competitor, albeit with much better component parts. May be more cost-acceptable than Option 2 or 3 but there may be just too many alternatives out there to differentiate this configuration.

Keeping the product tied to specific JBL designs may be OK but I think it would limit reach into the market. Having the option to customize Option 2 to other configurations would make it more appealing. Obviously a more hands-on than Option #1 but far more usable to the typical sound-oriented or DIY-oriented user.


If I refer to my earlier post

http://www.audioheritage.org/vbulletin/showthread.php?42350-STOP-PRESS-Bombshell&p=430027&viewfull=1#post430027

Is this more along the lines of that you would like?
Btw option 2 could be customised to another loudspeaker system either commercial or diy. The plug in cards can be offered in a adjustable format.

[Robh3606]

Hello Ian

I like option 2. I like the added sub output. Are you planning on summing to mono or having it in stereo with the option to sum?

I am intrigued about option 3. Why are you including a measurement system??

Rob:)

[Ian Mackenzie]

Hello Ian

I like option 2. I like the added sub output. Are you planning on summing to mono or having it in stereo with the option to sum?

I am intrigued about option 3. Why are you including a measurement system??

Rob:)

Hi Rob,

Summed mono or stereo sub can be switched.

The inclusion of a measurement kit is an option but will be priced as a package.

In the 1980’s companies like Sony and Accuphase made elaborate analogue crossovers with plug in modules with different crossover frequencies and slopes. They were deemed the ultimate solution for a hi end hifi system using system of art drivers.

But no driver is perfectly linear and the shape and location on a baffling has a significant effect on the system overall integration and frequency response. The crossover characteristics therefore need to consider these factors.

The above 1980’s crossover assumed text book drivers and results when integrated into a system. This is never the case in practice.

So the inclusion of a measurement kit is a tool to close the loop on optimising the overall results objectively and subjectively with listening . Listening is important but measurement guides the user in dialing in the system.

This also applies to setting the precise driver levels, accounting for room gain to achieve correct system tonal balance and fine adjustment of horn response all come into play. So the owner buys the product and can buy other additional plug in cards with the evolution of the loudspeaker.

Setting up an active system is not necessarily straightforward. We found Setting the levels important and users found this challenging. It requires a procedure as power amp sensitivity can vary and adjustment by ear is inconsistent.

I have such a design(s) mapped out and are designing and evaluating the building blocks.

I will have a portal on my website where a new customer or product owner can specify the product or product update and have the solution provided.

The design will focus a very low residual noise below -100 dB. A filter card may have nose below -110 with good design practice.

On paper you often see distortion rise below 1.00 volt output of a preamp because the test is total THD plus noise. The thing is that class A circuits are very linear with unmeasurable distortion at low signal voltage levels.

So the problem is noise and hum. This points to low impedance circuits which means the active devices must be able to drive sufficient current to maintain linearity and low distortion. This requires specialised audio circuits with very low noise and distortion with massive headroom. Such hardware with SOA performance is used in the recording and broadcast industries.

The crossover functionality, equalisation and other special purpose modules will be plug in.







The business will offer other key resources to support the product owner.


Without any means of measurement obtaining a good result can be time consuming and difficult.

[Ian Mackenzie]

Hi All,

I thought l would let you know where this is at.

With the flux of time during Covid 19 there has been some pondering of matching needs to product features and benefits.

With that in mind l am interested in your impressions and thoughts on the following:

Option 1.
A simple to use stereo 2 way universal analogue active crossover with continuously adjustable crossover points from 200-1500 hertz or similar.

24 dB LR slopes, state variable with balanced/unbalanced inputs and outputs.
Designed with premium TI audiophile chips and hi quality Wima capacitors and high quality pots.

This will be an improved Ashly or other universal crossovers like the Rane.

The idea is too keep it simple for those who want premium sound quality but aren’t into taking the lid off and making fine adjustments.

It won’t cost an arm and a leg because you will deal direct with the factory.

Option 2.
A stereo 2 way analogue active crossover that can be set up for specific Jbl systems using plug in cards.
In concept like the DX1. It will also feature a sub out put with an optimal low pass filter.

The crossover frequency, slopes ect are all set precisely for your particular Jbl systems.

The design will use premium class A Jfet buffers and high headroom studio quality discrete op amps.
Available in unbalanced as this crossover is for consumer hifi fanatics. Balanced connection and circuits add cost and complexity and frankly don’t promise improvement in sound quality.
All parts are of the highest quality. This product will be endorsed by Greg Timbers.

Option 3.

A Stereo 2 way or Tri amp analogue active crossover for the audio amateurs who enjoy building project loudspeakers of their own design.

The design will feature premium class A buffers like option two but with adjustable plug in crossover cards for crossover points and slopes. Special purpose plug in cards will be made available for equalisation of low and high frequency drivers and phase alignment of low and mid frequency drivers.

It will available with unbalanced or balanced connectors to a customers requirements.

Option 3 will be sold with the Dayton Omni Loudspeaker measurement system.

I have a reasonable inventory of popular JBL small and large format compression drivers and a growing collection of horns and woofers. So I can offer users with ball park crossover set up guidance.

Why Analogue? Because it’s simple with not a lot to learn and adjust. The focus is on doing the least damage to your precious analogue source. Vinyl is well and truly back and it sounds incredible with with a pristine signal path.

I have some state of art test abs measurement equipment on order.

Just a show of hands would be useful or other ideas.

Ian

Option 2 fleshed out for now.

Basic description
A stereo two way crossover with preset plug in crossover cards with D connectors and front panel level controls.

The user
The product is primarily for users of premium consumer JBL and sort after JBL vintage loudspeakers and other loudspeakers configured for bi amp operation. Audio amateurs will find application with the design of their own project loudspeaker system.

Cards will also be available for other consumer loudspeaker of popularity that have bi amp capability. Adjustable plug in cards will be made available including adjustable crossover frequency and crossover slopes.

Specification - draft
The front panel will have adjustment for both Low and High Levels for left and right loudspeakers, a power indicator.
The level tim controls will have a range of +6 db to - 20 db.
24 VDC power input jack from an external smps.
The outputs and inputs for Left and Right Low and High channels outputs and a left, right and mixed mono sub output for external self powered subwoofers. A rear panel D link connector is specified. This will simplify fabrication and aid user setup and installation.

The interior has plug in crossover cards which are installed by the factory on a main mother board.
The plug-in crossover cards can be installed or changed by the user with a removable top panel.
The std specification is up to 24 db LR but higher order filters can be achieved.
The mother board will have capacity for additional plug-in card modules to expansion capability to a fully active two way loudspeaker system.
This modules include LF Shelf to compensate for room boundaries, LF Boost, Room EQ Notch, LF phase shift (delay), Horn EQ with trim adjustment.
The motherboard can be configured for mono three way operation (4 way with sub output)

The interior has low voltage DC power supply.
Internal are some adjustments to assist with earthing to minimise earth loops
The product is packaged with a simple set up tool and a more advanced set up option available as an add on sale.
The chassis is made of machined and anodised aluminium panels and is solidly constructed.
Dimensions 18" x 4" x 15"
Weight 15 Ibs.

Specification and design
Low Noise Linear System Jfets, Sparko Labs and Sonic Imagery discrete studio grade operational amplifier modules.
Bourins and TDK potentiometers
Wima polyropolyne capacitors
Vishay resisters

Noise - 100 db
Distortion less than 0.002%
Frequency response 20 - 20,000 hertz +-0.25 db

Price POA based on a users requirements which will be unique in many cases. So you only buy what you need and can update and expand later.

[Dr.db]

Awesome project, thumbs up!!!

[Ian Mackenzie]

Thanks

[Ian Mackenzie]

Btw the above was close to my original thinking early on.

Okay this is the thing:

Because there is a sub out there are two or three options.

1. Unfiltered sub out for an external self powered sub with built in low pass crossover and power amp.
2. Filtered low pass sub out for an external Diy sub with an external power amp.
3. As per option 2 with a high pass crossover on the main Low output. This will enable a main Low band pass filter. For example a crossover at 100 hertz to a mid bass horn or configuration of a 4355 or 4345 to an active 3 way monitor.

So the design is Transversal is its functionality.

Different user groups want different things. But the common denominator is the loudspeaker or proposed loudspeaker the crossover is allied to. This type of Transversal configuration allows the user to Step - Up the functionality to a higher level of active operation in the evolution of his overall system.

More options:
4. On the high output channel there are additional options to incorporate programmable horn EQ to smooth the horn and or extend the horn response in the case of a CD design. This Step - Up in functionality removes the in-build high pass passive crossover and passive EQ.

So there is application for multi way monitor users who want to Step - Up to 3 way active in a multi way monitor or Step to full active of a two way monitor.

This sort of flexibility supports project loudspeaker users who plan to build out their own augmented two way system and helps overcome the limitations of high sensitivity two way designs.

I haven’t looked at it yet but a plug in module that offers an adjustable room curve is also possible.

Offering a chassis that anything to anyone is needlessly complicated and confusing and ineffective. I may offer a mini version chassis of the above that is a plug in set and forget box for those who aren’t the tweaking type of user.

Because this is an open public forum there are limits to disclosure of the design.

If anyone here has specific questions please pm.

Thank you to those who offered feedback.

Once Christmas is out of the way start on the detailed design.

[Ian Mackenzie]

Attached are some of the voltage EQ and FR curves with the crossover.

This follows the protocol of measure, test and learn.

The user can obtain excellent imperial results with a measurement kit such as REW or the the Dayton kit.

The crossover’s objective is to add as little or no noise or distortion as possible while being flexible in attaining the crossover transfer function as intended by the loudspeaker designer.

In terms of economics yes there is a start up cost in terms of the crossover and an additional stereo power amp. However this cost is offset by:

1. A superior dedicated high frequency amplifier.
2. Flexibility of trialling different settings to evaluate the optimal performance.
3. Removal of expensive passive crossover parts.
4. Removal of complex trial and error design of passive crossover networks which can have
unpredictable results due to interaction with the drivers impedance.
5. More efficient use of power and superior diaphragm control resulting in lower distortion,
improvements in resolving power and transient performance.

It’s another step closer to the music according to feedback from trials. The user forgets about the equipment and becomes emotionally connected to their music collection.

[Robh3606]

Hello Ian

Looking at your first graph you seem to have some significant gain below 20Hz. Are you going to have a highpass filter there in actual use?? Anyone using a turntable could have some issues with any gain between 10 and 20 Hz not to mention anyone using reflex boxes in conjunction.

Rob:)

[Ian Mackenzie]

Hi Rob,

That’s a good point.

In production these EQ curves will have limits put on them and bandwidth limiting filters to avoid excess sub sonic gain. That will all be worked out in product field trials.

[Ian Mackenzie]

Hello everyone who has commented in this thread and the followers who are interested.

An update

Here in Down Under the state boarders are re opening on the 17th of December 2021. That signals the green light for the economy and logistical things important to business to start moving again. Melbourne has had longest set of lockdowns on the planet! So for that and some other reason am in the process of relocating to the Sunshine Coast in Queensland. Not far from Steve Irwin’s Australia Zoo.

So l am interested to pick up on where l left off in this thread gleaning insights from anyone interested in a more up to date active crossover with origins based on the DX1.

1. To kick off some new interest over a period of time there have been calls for SH DX1 Crossovers, and crossover plug in PCB’s.

I would like to see a show of hands for general interest in meeting that need?

Apologies for the detailed post below

Put simply

Are you in favour of one box can do all?

Are you in favour of expanding on product capabilities as you go?

For the Thinking Cap Customers do you want access to fine tuning things like bass response, CD horn EQ adjustment from the front panel?
Or are you cool with tweaking your Diy loudspeaker with internal adjustments? See my comments below.

[Ian Mackenzie]

Edited text and added a pdf diagram to make the post easier to understand


http://www.audioheritage.org/vbulletin/showthread.php?42350-STOP-PRESS-Bombshell&p=430027&viewfull=1#post430027

http://www.audioheritage.org/vbulletin/newreply.php?do=newreply&p=430950

http://www.audioheritage.org/vbulletin/showthread.php?42350-STOP-PRESS-Bombshell&p=433097&viewfull=1#post433097

http://www.audioheritage.org/vbulletin/showthread.php?42350-STOP-PRESS-Bombshell&p=433118&viewfull=1#post433118

http://www.audioheritage.org/vbulletin/showthread.php?42350-STOP-PRESS-Bombshell&p=433121&viewfull=1#post433121


http://www.audioheritage.org/vbulletin/showthread.php?42350-STOP-PRESS-Bombshell&p=433125&viewfull=1#post433125

This list of posts summarises the direction of the discussion at the time.

I have a some questions?

There is interest in Option 2 and or a Blend of Option 2 + 3. Great.

A. My question is would you prefer a product that can be configured in a single chassis to provide a number of
configurations and features at the outset with items 1,2,3 and 4? Version A Yes/No

Or

Would your prefer a simplified crossover as with items 1, 2 with the option to be able to expand the crossover
capability with other additional chassis's that can be connected to provide 3 and 4? Version B Yes/No

1. Stereo Bi amp
2. Stereo Bi amp with stereo Sub outs (no sub crossover
3. Stereo Tri amp with Sub outs and a crossover filter, a Low or Mid out with low and high pass crossover filters, and a high crossover filter. Adjustable filters available via internal adjustments.
4. Options for low frequency shelf filters, driver EQ, Room Curves EQ, CD horn EQ, Sub sonic filter, driver Delay. Full active via internal adjustments.


Human Connectivity.

Question?
Are you comfortable with accessing the internal crossover plug card inside the chassis by taking the lid off? This is done with the DX1 crossover and the JBL 5234 and JBL 5235. Yes/No.

Or

Would you prefer to have a slot for example that you put the crossover cards in at the front or the rear. The Accuphase active crossovers took the approach. Yes/No


Access to Adjustments item 4 - Advanced Adjustments for the invested thinking cap customer.

Question?

Would you prefer to access the item 4 adjustments internally on optional plug in modules with labelled rotary trimmers or Dip switches or small knobs mounted on the PCB modules internally. By using a screw driver and a measurement system the adjustments can be set accurately.

Lower cost
Busy internally
Optional plug in modules and can be acquired to customise a particular need. Buy as you need.
Only accessible internally
Requires removal of chassis lid
Rotary trimmers and Dip switches - fiddly, potential for mistakes adjustment of wrong module.
Requires a measurement system for accurate system adjustment.

Note : Subject to space and design requirements we may be able to offer small knobs and small labels with a two or three tier PCB module to assist the user in making the adjustments

NOTE : All items in item 4 with Version A are optional and are plug in modules where that are accessed internally with trimmers and dip switches and a small screw driver. Yes/No

Or

Would you prefer to have front panel access to all or some of these adjustments using knobs and switches in Version A - Single Chassis? Yes/No

Busy front panel
Easy to access the adjustments
Costly to implement
Higher upfront cost a item 4 is purchased with the single chassis.

Or

Would you prefer to have front panel access to all or some of these adjustments in an expansion chassis per Version B. Yes/No

Buy the adjustments as a separate Chassis
Permanent
Front panel mounted adjustments in a single extension chassis - Version B
Front panel accessable
Can be adjusted by hand for convenience
Requires a measurement system for accurate system adjustment.
This would comprise of a number of front panel mounted knobs and switches and would be a permanent.


Item 4 listing of Variable Adjustments for :

Low frequency shelf filter below 100 hertz (single control Left and Right)
Room EQ bump filters. below 300 hertz (3 controls per filter Left and Right per filter) Two bands
CD horn EQ. (3 controls per filter Left and Right) One band
Driver EQ. (3 controls per filter Left and Right). Two or three bands
Driver Delay. (1 control per crossover output). Two or three bands

Bare in mind the adjustments in item 4 really require a microphone measurement to make it worthwhile.
This is not that difficult as it might seem with some understanding of the relevant techniques.

There are limitations to making these adjustments by ear other than a basic bass and treble tone controls.
You might switch in and out a low frequency filter to hear the difference. Once correctly set which can take a period of time with objective measurements and subjective assessment. The user generally won't make further adjustments.

You might set it and leave it or need to make a numbers of changes with measurements over a period of time.
Once the adjustments are made they are out of the way internally and you can acquire them when you need them.

Or you might prefer the appearance of front panel visible controls and the convenience of front panel access. It will resemble a knob farm and cost more are to implement.

If the customer is building a clone and one of the drivers is now discontinued we can provide technical support for either a modified passive network or a active network. The execution in the active design is much easier and less expensive if the customer has some spare power amplifiers he can utilise.

The full active level is an advanced user scenario. I will be offering user support with demonstration webinars, technical tips, design examples.

I am interested in your thoughts and opinions.

[Riley Casey]

Reinventing the FDS360 ?

[Ian Mackenzie]

Reinventing the FDS360 ?

Your showing your age...LOL.


In some ways yes as to the functionality.

I am not out to make a crossover that is a universal one size fits all or will be everything to everyone.

The application or approach is different in that the active crossover is "tuned" precisely to a defined loudspeaker as the loudspeaker designer intended for the "Plug in and it goes" consumer customer. These are loudspeakers designed for bi amp operation. The consumer customer rarely if ever has the capability or the means to do this precisely. By focusing on one loudspeaker we can do that really well.

Then if this customer becomes more curious and adventurous they can take over the controls of the aircraft as it were and have fun flying it.

But careful what you wish for.

This is the "Thinking Cap Customer". We given the a maps, charts and teach them how to navigate, take off and land the aircraft.

They can progress in sophistication and complexity make the loudspeaker fully active.

This can include modifying the frequency response to improve the subjective performance in their environment or to their own preferences or minimise an annoying acoustic anomaly.

Or modify the loudspeaker design if they wish.

This might included different compression drivers, woofers and horns etc. The original divers might not be available for a particular loudspeaker design the customer wants to clone. So we offer a precision crossover characteristic to enable the customer to use an alternative driver. We have the technical resources to do that. We can offer more sophisticated crossover characteristics to improve on the original legacy design.

We can teach the customer how to make meaning acoustic measurements as part of the product offering. Once they pass this hurdle they will become more invested in their loudspeaker system and will be able to start making informed decisions around shaping the subjective results.

There are some pitfalls to doing this so its less risky to be selective in the approach by giving the customer a product that goes beautifully at the outset rather than over complicate it and overwhelm them.

[Ian Mackenzie]

Edit. Bells and Whistles or Useful Tools

“4 Options for low frequency shelf filters, driver EQ, Room Curves EQ, CD horn EQ, Sub sonic filter, driver Delay. Full active via internal adjustments.”

In looking at the adjustments in item 4 above you may ask are they bells and whistles or are they something l may need.

This is the thing.

An existing JBL loudspeaker System
When you have a predetermined JBL loudspeaker system which is Bi amp ready and want to simply Biamp a number of the adjustments are taken care of for you within the overall design of internal passive crossover such as driver response shaping, horn equalisation.

What we do.
What we do is look at the existing passive crossover and engineer the active crossover characteristics from that by measurements of what the passive crossover is doing with the drivers connected. We look at the whole picture. Not just the crossover slopes and determine the best approach for Bi amp operation. This might include some mild shelf LF EQ at 35 hertz, a room resonance Low Q dip at at 290 hertz and superior active filter slopes on the woofer.

We can’t account for every possibility in your own listening room but we can provide you with some optional tools like a tool box.

Your listening environment
For example you might be stuck for space and you can’t move the loudspeaker for the smoothest bass. Bass response in a domestic living space can be an involved subject. But we can help you assess your options and provide you with the most effective tools.

Product Support
After some discussion with us you buy a measurement mic and a USB interface so you can explore what’s happening with your JBL system with REW. You discover a bump in the response at 100-150 hertz and a sharp80 peak at 60 hertz.

Recommendation
We recommend you move the loudspeaker back as close to the wall as post to move the Combe effects that cause the bumps further up to a higher frequency. You re measure the the bump is now at 80 hertz.

You can’t eliminate low frequency room interaction with EQ but you can reduce the issue with carefully use of EQ.

We provide you with a set of Low Q EQ and High Q EQ plug in cards with instructions for installation and adjustment. You install the plug in modules and make adjustments by following a demonstration clip we provide you on a Zip drive which explains how to interpret your REW measurements and how to go about adjustment of your plug in modules. You do this on a Saturday afternoon and sit down to listen to your favourite tuned Saturday evening.

The improvement
You find the bass has more clarity and the system has better overall tonal balance. The listening experience is more enjoyable because you can focus on the music.

[Ian Mackenzie]

The. Thinking Cap Customer

You own JBL 4435 and you have longed for a better power amp but it’s really expensive.
You read a review of a Quick Silver power amp but is rated at only 50+50 watts. On the forums you read about Bi amping the 4435 and start to think about your options.

You contact us for advice on Bi amping the 4435.

The Recommendation
We discuss your situation with you, your budget and make a recommendation.

You order a Stereo Biamp active crossover with a plug in crossover module for the 4435.
You also order a kit of parts to assemble a charge coupled passive horn CD EQ for the bi radial horn.

Getting it all together
The crossover and the kit arrive. On a Zip drive we provide you with installation and set up instructions for the active crossover. We provide you with diagrams and instructions on assembly of the charge coupled kit and an installation guide.

Your new Quicksilver power amp arrives.

You refer to the installation guide for the active crossover and connect everything up.
We give you support to make some fine adjustments and you obtain the correct balance with the woofer and the horn.

The results
You listen to some of your favourite tunes on Saturday night.
The loudspeaker is far more revealing of fine details and the bass is firmer.
You feel closer to music and start to rediscover your record collection.

[Ian Mackenzie]

These scenarios are typical of how loudspeaker owners approach using an active crossover. They give you an idea of how the active crossover and some optional modules and kits can work together to improve your listening experience.

[Ian Mackenzie]

Okay, I have some good news.

After a lot thought in terms of the original idea for a configurable active crossover to suit a particular users needs I come up with a novel way of implementing the idea.

In conventional passive and active crossovers we think of multiway systems in terms of is it a two way, three way or four way system?

But suppose for a moment we stop and look at how a user starts to think about his particular system and what he would like to do next?

Or how he might want to build a clone using some alternative drivers or horns. Then the question of the crossover network comes up?

I am seeing more evolution in the use of alternative drivers where newer drivers are available or where a mid range cone driver is now N/A and how to sort out the passive crossover network. Or it might be a new woofer or a large format compression driver. Passive networks are complex to design and also really really expensive to assemble with high quality parts.

Yes this is the problem. I see lots of requests on how to do it.

So what this thing is going to do is allow a user to break down what's going on in his particular loudspeaker system to a level not easily done before in a controlled and precise way. The user is going to be able to experiment with it and do some tweaking. People like to tweak.

I told Greg about it yesterday and this is his reply:

"I really love the idea. You are basically talking about a monster DX-1. Unfortunately the DX1 was not set up for anything more than the crossover function. Your box is capable of so much more".

A Monster DX1.

So in terms of the next steps I am drafting up the overall design. The key has been to find a way of making it work in the practical sense so that only whats relevant is in use.

I nearly fell of my chair my chair when I figured this out.

Back in my days at uni I did some systems analysis and design for a potential career in IT. I ended improving and testing processes for banks. What they do is teach you how to look at systems and break down systems into different levels. What's on the face of it is a simple process.

But under that process you have inputs, more actual processes, interactions with the user and outputs. Passive crossovers are often compromises and often an active crossover doesn't get it right because people don't really understand passive crossovers and how they interact with real drivers.

Quite often the passive crossover design bends the response of the system to obtain a listenable outcome in the room.

I have new engineer to assist in the design of the project. He has spent over four decades designing mixing consoles and Hifi equipment, has a number of patents and is currently consulting. The aim is to obtain some really good specifications like really low noise and distortion.

If anyone has any requests on what they would like to do with their system post it here.

[Ian Mackenzie]

Okay, I have some good news.

After a lot thought in terms of the original idea for a configurable active crossover to suit a particular users needs I come up with a novel way of implementing the idea.

In conventional passive and active crossovers we think of multiway systems in terms of is it a two way, three way or four way system?

But suppose for a moment we stop and look at how a user starts to think about his particular system and what he would like to do next?

Or how he might want to build a clone using some alternative drivers or horns. Then the question of the crossover network comes up?

I am seeing more evolution in the use of alternative drivers where newer drivers are available or where a mid range cone driver is now N/A and how to sort out the passive crossover network. Or it might be a new woofer or a large format compression driver. Passive networks are complex to design and also really really expensive to assemble with high quality parts.

Yes this is the problem. I see lots of requests on how to do it.

So what this thing is going to do is allow a user to break down what's going on in his particular loudspeaker system to a level not easily done before in a controlled and precise way. The user is going to be able to experiment with it and do some tweaking. People like to tweak.

I told Greg about it yesterday and this is his reply:

"I really love the idea. You are basically talking about a monster DX-1. Unfortunately the DX1 was not set up for anything more than the crossover function. Your box is capable of so much more".

A Monster DX1.

So in terms of the next steps I am drafting up the overall design. The key has been to find a way of making it work in the practical sense so that only whats relevant is in use.

I nearly fell of my chair when I figured this out.

Back in my days at uni I did some systems analysis and design for a potential career in IT. I ended improving and testing processes for banks. What they do is teach you how to look at systems and break down systems into different levels. What's on the face of it is a simple process.

But under that process you have inputs, more actual processes, interactions with the user and outputs. Passive crossovers are often compromises and often an active crossover doesn't get it right because people don't really understand passive crossovers and how they interact with real drivers.

I have new engineer to assist in the design of the project. He has spent over four decades designing mixing consoles and Hifi equipment, has a number of patents and is currently consulting. The aim is to obtain some really good specifications like really low noise and distortion.

If anyone has any requests on what they would like to do with their system post it here.