Integrating vintage Transmission Line Floorstanders into a Multi-Sub setup

[soundflo_w]

Hi everyone,
I’m in the process of building a home theater system in my living room and have the opportunity to use my father’s vintage Quadral Vulkan MKII Transmission Line speakers, including the original pre- and power amp stages.
The Vulkan MKII is a massive 55kg speaker, with the TL tuned very low (I believe around 20-25 Hz).

Quadral Vulkan Mk II | Hifi-Wiki

www.hifi-wiki.de

My Dilemma:
Initially, I planned to run bookshelf mains and a standard Multi-Sub Optimizer (MSO) routine with 3-4 dedicated subwoofers and a high-pass filter on the mains. With the Quadrals however, cutting them off at 80Hz feels like a waste of their massive cabinets and low-end extension making them very much oversized without benefit.
The Goal:
I want to utilize the Vulkan’s sub-bass capabilities as part of a multi-sub strategy and reduce the amount of dedicated subwoofers to two. Essentially, I’d like to treat the low end of the Quadrals as two additional subwoofers (making it a 4-sub system in the eyes of MSO) while still using them as my L/R mains.

(The Vulkan MKII allows for individual access to the three drivers. I considered driving the woofers separately, but the internal crossover point to the mid-range is at 400 Hz. If I treat the woofer as a dedicated sub-channel I would make them useless as mains (80-400Hz hole)

My Question:
Is there a way to use the full capabilities of the Quadrals?

Looking forward to your technical insights!

 

[janbth]

The first thing that springs to mind is to get an AVR with Dirac ART. Dirac ART doesn't do bass management in the usual way, but allows you to use your mains to their full capacity with your subs supporting them as needed. This will possibly let you get away with fewer subs as well.

 

[markstein]

Hi everyone,
I’m in the process of building a home theater system in my living room and have the opportunity to use my father’s vintage Quadral Vulkan MKII Transmission Line speakers, including the original pre- and power amp stages.
The Vulkan MKII is a massive 55kg speaker, with the TL tuned very low (I believe around 20-25 Hz).

Quadral Vulkan Mk II | Hifi-Wiki

www.hifi-wiki.de

My Dilemma:
Initially, I planned to run bookshelf mains and a standard Multi-Sub Optimizer (MSO) routine with 3-4 dedicated subwoofers and a high-pass filter on the mains. With the Quadrals however, cutting them off at 80Hz feels like a waste of their massive cabinets and low-end extension making them very much oversized without benefit.
The Goal:
I want to utilize the Vulkan’s sub-bass capabilities as part of a multi-sub strategy and reduce the amount of dedicated subwoofers to two. Essentially, I’d like to treat the low end of the Quadrals as two additional subwoofers (making it a 4-sub system in the eyes of MSO) while still using them as my L/R mains.

(The Vulkan MKII allows for individual access to the three drivers. I considered driving the woofers separately, but the internal crossover point to the mid-range is at 400 Hz. If I treat the woofer as a dedicated sub-channel I would make them useless as mains (80-400Hz hole)

My Question:
Is there a way to use the full capabilities of the Quadrals?

Looking forward to your technical insights!

You may run a MSO optimization with 2x main speakers (w/o high pass filter) and 2x subwoofer (with low pass filter) setup. This is know as "Geddes" approach.

 

[soundflo_w]

You may run a MSO optimization with 2x main speakers (w/o high pass filter) and 2x subwoofer (with low pass filter) setup. This is know as "Geddes" approach.

Thank you for the suggestion.

Could you please go into a little more detail how this works? Do I measure the main speakers up to 20kHz or just bass?
As far as I know, MSO works with delays. Wouldn't it be a problem when the optimization finds differing delays for the main speakers since that delay also applies to everything above bass frequencies?

 

[Oddball]

Hi everyone,
I’m in the process of building a home theater system in my living room and have the opportunity to use my father’s vintage Quadral Vulkan MKII Transmission Line speakers, including the original pre- and power amp stages.
The Vulkan MKII is a massive 55kg speaker, with the TL tuned very low (I believe around 20-25 Hz).

Quadral Vulkan Mk II | Hifi-Wiki

www.hifi-wiki.de

My Dilemma:
Initially, I planned to run bookshelf mains and a standard Multi-Sub Optimizer (MSO) routine with 3-4 dedicated subwoofers and a high-pass filter on the mains. With the Quadrals however, cutting them off at 80Hz feels like a waste of their massive cabinets and low-end extension making them very much oversized without benefit.
The Goal:
I want to utilize the Vulkan’s sub-bass capabilities as part of a multi-sub strategy and reduce the amount of dedicated subwoofers to two. Essentially, I’d like to treat the low end of the Quadrals as two additional subwoofers (making it a 4-sub system in the eyes of MSO) while still using them as my L/R mains.

(The Vulkan MKII allows for individual access to the three drivers. I considered driving the woofers separately, but the internal crossover point to the mid-range is at 400 Hz. If I treat the woofer as a dedicated sub-channel I would make them useless as mains (80-400Hz hole)

My Question:
Is there a way to use the full capabilities of the Quadrals?

Looking forward to your technical insights!

Couple of points.

Vulkan's are not subs - they have what people call "useful" output below some point - not sure if 80 or 60hz, but probably not lower. Subs are different and they will excel at these points, commensurate with their abilities, and up to their point of roll-off. At the end, it all depends on SPL you need. Even mighty subs do only around 100dB at 20hz.

You still might get the benefit of Vulcans as I would imagine (purely a guess due to size and house they come from) they can do higher SPL at lower distortion than the bookshelves.

If you are looking for top bass performance, then ART is the easy way out.

Not sure what is your bass management though. Some bass management solutions would allow you to duplicate the low end signal to both mains and the subs - called "double bass" or LFE+main. With lots of REW, this could kind of work relatively well.

 

[andyc56]

You may run a MSO optimization with 2x main speakers (w/o high pass filter) and 2x subwoofer (with low pass filter) setup. This is know as "Geddes" approach.

I would strongly advise against doing this.

When MSO first started out in 2015, it had only "subs+mains" configurations, for which it tried to optimize the integration of mains and subs among other goals. This was because the dominant "room correction" system at the time was Audyssey, which was notorious for getting the integration badly wrong. The idea was for MSO to fill that gap.

Later, as more robust room correction systems like Dirac became more popular, and did the integration right, people wanted to optimize just the subs in MSO and let the room correction do the integration. This led to the introduction of "sub-only" configurations to MSO, which soon became the dominant usage of it. Subs+mains configurations fell by the wayside, and lagged behind sub-only configurations in terms of available features. But if you want to use your main speakers to substantially contribute to low bass output, then a sub-only configuration won't help with that.

You can see a brief summary of the Geddes technique in the MSO "Tech Topics" documentation. Scroll down to the bottom of the page, and you'll see "Obsolete and Unsupported Topics". Click on the link beneath that, referencing the Geddes technique.

It's also worth mentioning why the Geddes technique worked at all. It was created around the assumption that people would be using Earl's main speaker design. These speakers, according to his own web site, have an anechoic low-frequency cutoff of 80-90 Hz. So they have a natural acoustical high-pass right around the frequency you'd normally introduce a crossover anyway. If you try to use that technique with main speakers having deep low-frequency extension, and you try to overlap subs and main speakers, you'll get a response hump that has to be removed with EQ both on the main speakers and subs. If instead you apply a low-pass filter to the subs at a very low frequency where the mains roll off, you'll lose the benefits of multi-sub optimization in the frequency range where it matters most.

I'd recommend Dirac ART for this application, as it's designed to allow for main speakers to have a substantial contribution to the response in the bass region at frequencies below which you'd normally have a crossover when using conventional bass management.

 

[Oddball]

I would strongly advise against doing this.

When MSO first started out in 2015, it had only "subs+mains" configurations, for which it tried to optimize the integration of mains and subs among other goals. This was because the dominant "room correction" system at the time was Audyssey, which was notorious for getting the integration badly wrong. The idea was for MSO to fill that gap.

Later, as more robust room correction systems like Dirac became more popular, and did the integration right, people wanted to optimize just the subs in MSO and let the room correction do the integration. This led to the introduction of "sub-only" configurations to MSO, which soon became the dominant usage of it. Subs+mains configurations fell by the wayside, and lagged behind sub-only configurations in terms of available features. But if you want to use your main speakers to substantially contribute to low bass output, then a sub-only configuration won't help with that.

You can see a brief summary of the Geddes technique in the MSO "Tech Topics" documentation. Scroll down to the bottom of the page, and you'll see "Obsolete and Unsupported Topics". Click on the link beneath that, referencing the Geddes technique.

It's also worth mentioning why the Geddes technique worked at all. It was created around the assumption that people would be using Earl's main speaker design. These speakers, according to his own web site, have an anechoic low-frequency cutoff of 80-90 Hz. So they have a natural acoustical high-pass right around the frequency you'd normally introduce a crossover anyway. If you try to use that technique with main speakers having deep low-frequency extension, and you try to overlap subs and main speakers, you'll get a response hump that has to be removed with EQ both on the main speakers and subs. If instead you apply a low-pass filter to the subs at a very low frequency where the mains roll off, you'll lose the benefits of multi-sub optimization in the frequency range where it matters most.

I'd recommend Dirac ART for this application, as it's designed to allow for main speakers to have a substantial contribution to the response in the bass region at frequencies below which you'd normally have a crossover when using conventional bass management.

We would first have to know what is the bass management and EQ that OP is using. Than we can take it from there.

As far as ART, it might or might not take up your large beds as support - mostly depending on sub firepower. But as I noted, large ones will generally have higher SPL and lower distortion which is not to be overlooked if your are pushing levels to reference. If not, they agree they might be a bit wasted if sufficient sub power.

 

[markstein]

Thank you for the suggestion.

Could you please go into a little more detail how this works? Do I measure the main speakers up to 20kHz or just bass?
As far as I know, MSO works with delays. Wouldn't it be a problem when the optimization finds differing delays for the main speakers since that delay also applies to everything above bass frequencies?

You need to do all acoustic measurements (each main speaker and each sub at each listening position) with acoustic loopback (I guess you are using REW). The measured range does not need to be higher than 500Hz, however, I recommend to look at a full measurement of your mains to get an idea of your target bass SPL you will be using in MSO.

Regarding background info for the Geddes approach, you may look at this link, and of of course at the MSO online help or just do a web search:

Geddes Approach on Multi-sub Bass Optimization: Video Presentation

Geddes Approach on Multi-Sub Bass Optimization: Video Presentation AV NIRVANA is happy to release one of our first video presentations addressing technical topics. This video is on the multi-sub approach developed by Earl Geddes, a man I consider an important mentor and influencer of my...

www.avnirvana.com

 

[soundflo_w]

Thank you all very much for your responses!

Regarding my current setup: I haven't committed to any specific hardware or bass management solution just yet. I’m willing to go with whatever proves to be the most "ideal".
I'm familiar with studio setups, routing, DSP, measurements and have successfully integrated 2 subs with my Neumann KH120s via Behringer DCX2496 Ultra-Drive Pro. However, I'm a complete novice when it comes to home cinema (I don't even own a TV yet).
As far as I understand, an AVR would make the most sense as the core component in the living room, as it provides a streamlined way to handle music streaming and movies while also allowing me to keep my digital piano permanently connected (for casual, non-studio use).

This would also play well with the common recommendation for ART. Simplest and best solution: ART-ready AVR, right?
Big downside is the hefty price tag for someone with DIY aspirations

One potential path I haven’t quite given up on finding is a more 'manual' solution. I’m wondering if I can achieve 80-90% of the result manually with only the AVR-internal filters and delays.

 

[soundflo_w]

Regarding Geddes approach or "double bass"/LFE+main:
Yes I could see this working relatively well.
My first thought was: A slight low shelf EQ on the mains and low-pass on the subs at "crossover". Adjust sub levels to desired house curve.

But couldn't I just run both the mains and 2 subs through MSO for an optimized result?
Are there even 'budget-friendly' AVRs that offer granular enough manual controls to actually implement the results generated by MSO? If not, then I would need a DSP anyway, which would close the budget gap to ART. I'd love to hear your thoughts on whether a manual AVR-based approach is even viable, or if the hardware limitations make it a dead end.

 

[soundflo_w]

Another question: If I ran with ART, I would need the complete bundle (+Room Correction +Bass Control), right?

 

[Oddball]

Another question: If I ran with ART, I would need the complete bundle (+Room Correction +Bass Control), right?

Cheapest ART capable AVR would be Denon 3800H and you would need Dirac Live + Bass Control + ART (so all three). It should be under $2K. If it proves that AVR can't drive the LCR adequately (possible with difficult speakers, but overall unlikely), you can always buy external amp which are nowadays more affordable than before.

There are some threads where people claim that mini-DSP and MSO can get them to 90% of ART. That is definitely true for FQ response - could actually be 100%. For delay, not really sure what would be so effective as ART except double bass array (a difficult thing to pull off actually) or some really heavy room treatment (relatively expensive, large and not practical). I never did MSO and before ART had Audy setup where I could import REW filters and it worked pretty well in LFE+Main and LFE distribution scenario. But was so difficult to set up that it drove me crazy for months and months.

If you have $2K to spare, I would advise ART and then spend your free time on other activities than tweaking.

 

[Flaesh]

double bass array (a difficult thing to pull off actually)

It depends. First of all, it depends on the room.

really heavy room treatment (relatively expensive, large and not practical)

Same thing. Front subwoofer array and a couple feet of fluffy wool on the back wall.

 

[MaxxC]

My first post here. I got in to HiFi about 25 years ago. I’ve had many different Amps, speakers through the years. About 3 years ago I started thinking about building a final reference system.

The speaker I finally fell in love with are a pair of NSMT Audio Model 50 Jamaica speakers . They replaced speakers that literally cost twice as much. I thought the expensive speakers were almost perfect until I heard the Jamaicas. That was a whole new ballgame something I had never experienced

The Jamaicas are a midsize Double Transmission line 2 way speaker with the same high efficiency as your Dads 100db

If you can get the bass in your dads speakers to integrate it’s going to be way better then any subwoofer.

It has 3 major advantages over a subwoofer

1) Huge Cabinet
2) Transmission Line
3) Very High efficiency

The new ball game . Transmission lines properly done The bass is very deep powerful fast and articulate. It’s about as far away as you can get from one note, bloated slow bass.

The other factor is the very high efficiency of 100db. The overall dynamics in mime are simply amazing for a speaker of that size. Once you hear it you realize the primary appeal of very high efficiency speakers isn’t because they can play loud It’s because they have so much dynamics and impact, vivid and colorful like music being heard live. Probably the most amazing part of high efficiency speakers they sound great at low volumes. Those qualities there is life going on at low volumes. Not your usual flat and boring where you want to goose the volume up a little.

I would just take your bookshelf’s to your dads and A/B You might just want to
Forgo the bookshelf all together

Good luck