For you horn guys: What kind of compression driver are you using for high frequencies? Why that choice (if you know...)

[morricab]

Have a look at the Voigt pipe. This design has been around since the 1930s and very popular indeed with the diy scene.

Interestingly, a double tapered quarter wave tube (DTQWT) gives smoother bass as you tune the two "pipes" to different frequencies and this reduces some of the cancellations that happen in a normal TQWT.

 

[the sound of Tao]

The Cube Audio Nenuphar is tapered quarter wave tube single driver. The lack of crossover and very detailed presentation is quite apparent here... there does seem to be an overwhelming amount of information coming through though.

 

[Duke LeJeune]

TQWT. It's some kind of transmission line tapered bass, and apparently those who use it do use a high cut off

Ah. Yes, I built some back in the 80's. I think that placing the woofer halfway down the reverse-tapered line mitigates the response dip at the frequency where the line length is equal to one wavelength.

A ported box

It can be, but stuffing damps the Helmholtz resonance.

A "mass loaded transmission line" is also arguably a ported box, but with the port placed at a particular location which damps one of the internal resonance modes, if I recall correctly.

 

[Audiophile Bill]

Interestingly, a double tapered quarter wave tube (DTQWT) gives smoother bass as you tune the two "pipes" to different frequencies and this reduces some of the cancellations that happen in a normal TQWT.

Brad - are you designing your TQWT from scratch or using an existing design? I saw a good calculator on the MHL site if you want?

 

[morricab]

Brad - are you designing your TQWT from scratch or using an existing design? I saw a good calculator on the MHL site if you want?

I have a design in the computer already that I will likely start with but probably will require trial and error to optimize. This is where the digital xo accelerates the development. If the cabinet is wrong it won’t help of course.

 

[morricab]

The Cube Audio Nenuphar is tapered quarter wave tube single driver. The lack of crossover and very detailed presentation is quite apparent here... there does seem to be an overwhelming amount of information coming through though.

Cubes are good except for the highs, IMO, which despite the engineering effort to improve them, still sound like Whizzer highs. I don’t like Whizzer highs. The bass from Nenuphar is pretty good as are the mids.

 

[the sound of Tao]

So time for reflection as I’m temporarily in a preliminary choice loop... I am still at an early place in the DIY horn plan and I keep circling back to a fundamental point in the essential design strategy. Looking for any reflection points here if possible.

I’m chasing the same essential dilemma that many have faced before of (using a sub also) with either a 2 way V more multi way... then that also feeds back to the question of 1 inch V 1.4 inch V 2 inch compression drivers potentials and constraints.

Logic does say that I have the Pap horn which as a 2 way and is really just doing everything I could ask of it in terms of small to medium and even large scale music and covers all genres well in my medium scale room (5.6 x 7.2m). Also it will be getting an OB sub to augment it.

Desire leads me to consider a multi-way for use for primarily the biggest scale (classical) music for a larger room (which is future build in planning).

Wise voices (not mine) have said keep the Pap horn as a reference (and to play while developing the other) and then also do a new DIY as an alternate and (thanks Christoph) that fits as a great way to go.

So the dilemma is somehow I still keep circling back to proposing a better (in terms of build and parts) 2 way with a OB sub rather than stretching to going more horns. I am a coherency junkie but part of me says if this is to be an alternative setup I should just risk complexity and go for the more horns route (ie so going for both a 2 inch CD and a 1 inch CD for mids and from there on up above dual 15 inch mid bass woofers and multiple OB subwoofers)

or still try and keep with simpler (and hopefully more coherent) less ways with a much better beryllium 1.4 inch CD and try and cover mids and up as a wide ranger.

The 1.4 inch CDs could be the Radian 951pb-be or the BMS 4594HE coaxial neodymium (though the beryllium radian is more likely).

The 2 inch of the radian would be possibly the choice if I was adding a tweeter on top which could possibly then be the fostex T500AM mk2

A SEOS 24 autotech horn is looking like a good potential choice for the simpler 1.4inch option

For horns I really like/visually prefer iwata but the autotech 300 Iwata is however designed for a 2 inch CD.

If I got it all working right and felt it was the horn I’d ultimately live with I’d be happy down the track to then also cnc whatever horns I chose in a wood version.

My current birch Iwata horn is a 1.4 inch diameter but unsure of the exit angle or if it’s then the ideal horn for the 1.4inch Radian beryllium. I still could try this as an option but am getting that I should aim to just getting the best horn/horns for the best compression drivers as I still have the question of crossovers and active V passive to surmount. I am very much looking forward to trying this all out. Having a good setup already takes out any real pressure so I can afford to explore a bit and give plenty of time to it’s development.

Thanks for any thoughts or feed in
Cheers
Graham

 

[DaveC]

So time for reflection as I’m temporarily in a preliminary choice loop... I am still at an early place in the DIY horn plan and I keep circling back to a fundamental point in the essential design strategy. Looking for any reflection points here if possible.

I’m chasing the same essential dilemma that many have faced before of (using a sub also) with either a 2 way V more multi way... then that also feeds back to the question of 1 inch V 1.4 inch V 2 inch compression drivers potentials and constraints.

Logic does say that I have the Pap horn which as a 2 way and is really just doing everything I could ask of it in terms of small to medium and even large scale music and covers all genres well in my medium scale room (5.6 x 7.2m). Also it will be getting an OB sub to augment it.

Desire leads me to consider a multi-way for use for primarily the biggest scale (classical) music for a larger room (which is future build in planning).

Wise voices (not mine) have said keep the Pap horn as a reference (and to play while developing the other) and then also do a new DIY as an alternate and (thanks Christoph) that fits as a great way to go.

So the dilemma is somehow I still keep circling back to proposing a better (in terms of build and parts) 2 way with a OB sub rather than stretching to going more horns. I am a coherency junkie but part of me says if this is to be an alternative setup I should just risk complexity and go for the more horns route (ie so going for both a 2 inch CD and a 1 inch CD for mids and from there on up above dual 15 inch mid bass woofers and multiple OB subwoofers)

or still try and keep with simpler (and hopefully more coherent) less ways with a much better beryllium 1.4 inch CD and try and cover mids and up as a wide ranger.

The 1.4 inch CDs could be the Radian 951pb-be or the BMS 4594HE coaxial neodymium (though the beryllium radian is more likely).

The 2 inch of the radian would be possibly the choice if I was adding a tweeter on top which could possibly then be the fostex T500AM mk2

A SEOS 24 autotech horn is looking like a good potential choice for the simpler 1.4inch option

For horns I really like/visually prefer iwata but the autotech 300 Iwata is however designed for a 2 inch CD.

If I got it all working right and felt it was the horn I’d ultimately live with I’d be happy down the track to then also cnc whatever horns I chose in a wood version.

My current birch Iwata horn is a 1.4 inch diameter but unsure of the exit angle or if it’s then the ideal horn for the 1.4inch Radian beryllium. I still could try this as an option but am getting that I should aim to just getting the best horn/horns for the best compression drivers as I still have the question of crossovers and active V passive to surmount. I am very much looking forward to trying this all out. Having a good setup already takes out any real pressure so I can afford to explore a bit and give plenty of time to it’s development.

Thanks for any thoughts or feed in
Cheers
Graham

Sounds like an opportunity to build-in a proper bass horn.

If that built-in concrete bass horn covers ~20-50 Hz or so and you want the best results with large scale music I'd consider a multi-way horn system that uses the horns within their effective range combined with steeper filters, something more like @kodomo built vs covering more bandwidth with a single horn.

Personally, I don't listen to large scale music that much so I prefer using a wideband midrange. My speaker covers 400-15,000 Hz using the mechanical rolloff from the horn + a single cap to limit excursion a little more. Then a single cap to both crossover and attenuate the tweeter (Fostex T500). You may think about keeping your PAP system like this and a the big system for complex music in the other direction.

I think the tradeoffs are mainly a 4+ way horn system is more costly and complex, needs a big space and may take an exceptional amount of time and effort to put together. The simpler 2-3 way system is still a lot of effort, and imo can often be better for smaller scale music anyways. It will cost a fraction of the cost, time and effort to get to a place where results are good. Having a midrange that covers 400-15,000 Hz makes a multitude of potential issues mostly irrelevant.

I also think it's 100% necessary to have a reference system while putting your speakers together. I'd consider something in addition to the PAP speakers that's as neutral as you can find. I have Pioneer S-1EX (TAD Evolution towers in cheaper cabs) w/ modded Odyssey amps, nothing special but it's a good reference, the mids and highs are really excellent by any standards, that TAD Be tweeter is among the best imo. The PAP isn't a very standard speaker especially when used with a full range driver, it won't have as even a frequency response as a speaker designed with that as a priority.

It's hard to wrong with anything though, as long as it's a good implementation. One thing I noticed on my speakers that's a make or break issue, it's not straight forward to combine driver types. The coherence from a speaker has A LOT to do with the drivers sounding alike, it's not always a crossover issue. I went through quite a few tweeters and woofers, and finding ones that matched my midrange driver was really key to making it all come together. That T500 is super-neutral though, it's an exceptional tweeter imo... And for the same reason built-in horn subwoofers will be totally worth it!

 

[the sound of Tao]

Thanks Dave,
Yes... and I’ll have the Harbeth 40.2s also for sonic reference but the Paps are the speaker I am just drawn to listen to most all of the time so the reference point with the paps might just purely holistically be about which speaker makes me enjoy music the most.

Great thoughts.

I do enjoy subjective assessment and should accept the time this will likely take but no matter which way I head I will also enjoy the build process as well. I like playing with materiality and your comment on coherence makes complete sense. The Maggie 20.7s are the most coherent speaker I’ve had and it comes out of the coherent driver types. I’ve been surprised how coherent the paps are now but think that relates to its simplicity as well. I do think I’ll try and stage it so I build up to the project through time with some options for re-use or adaptability along the way.

Though if I design the subs as standalone they can serve either horns or maggies (plan c )... and could go without super tweeter initially and then add the supertweeter then if the top needs opening up.

The advantage of committing to having the super tweeter from the start as part would possibly be I could then go with the 2 inch Radian beryllium CD and that would let me also go with the autotech Iwata 300.

So it is perhaps coming back to what horn I prefer and which mid horn CD pairing will be the best choice. I can just go safer simpler with the Radian beryllium 1.4 inch in the SEOS and then have a plan (d) to still then add the fostex t500 the way that you have if it all then needs a tilt up.

But the notion of building coherency from the mid driver out also makes complete sense to me... it’s the way I try and balance the sound as well always teasing out from the mids but always still staying anchored in the mids. Much appreciated thank you.

 

[bonzo75]

So time for reflection as I’m temporarily in a preliminary choice loop... I am still at an early place in the DIY horn plan and I keep circling back to a fundamental point in the essential design strategy. Looking for any reflection points here if possible.

I’m chasing the same essential dilemma that many have faced before of (using a sub also) with either a 2 way V more multi way... then that also feeds back to the question of 1 inch V 1.4 inch V 2 inch compression drivers potentials and constraints.

Logic does say that I have the Pap horn which as a 2 way and is really just doing everything I could ask of it in terms of small to medium and even large scale music and covers all genres well in my medium scale room (5.6 x 7.2m). Also it will be getting an OB sub to augment it.

Desire leads me to consider a multi-way for use for primarily the biggest scale (classical) music for a larger room (which is future build in planning).

Wise voices (not mine) have said keep the Pap horn as a reference (and to play while developing the other) and then also do a new DIY as an alternate and (thanks Christoph) that fits as a great way to go.

So the dilemma is somehow I still keep circling back to proposing a better (in terms of build and parts) 2 way with a OB sub rather than stretching to going more horns. I am a coherency junkie but part of me says if this is to be an alternative setup I should just risk complexity and go for the more horns route (ie so going for both a 2 inch CD and a 1 inch CD for mids and from there on up above dual 15 inch mid bass woofers and multiple OB subwoofers)

or still try and keep with simpler (and hopefully more coherent) less ways with a much better beryllium 1.4 inch CD and try and cover mids and up as a wide ranger.

The 1.4 inch CDs could be the Radian 951pb-be or the BMS 4594HE coaxial neodymium (though the beryllium radian is more likely).

The 2 inch of the radian would be possibly the choice if I was adding a tweeter on top which could possibly then be the fostex T500AM mk2

A SEOS 24 autotech horn is looking like a good potential choice for the simpler 1.4inch option

For horns I really like/visually prefer iwata but the autotech 300 Iwata is however designed for a 2 inch CD.

If I got it all working right and felt it was the horn I’d ultimately live with I’d be happy down the track to then also cnc whatever horns I chose in a wood version.

My current birch Iwata horn is a 1.4 inch diameter but unsure of the exit angle or if it’s then the ideal horn for the 1.4inch Radian beryllium. I still could try this as an option but am getting that I should aim to just getting the best horn/horns for the best compression drivers as I still have the question of crossovers and active V passive to surmount. I am very much looking forward to trying this all out. Having a good setup already takes out any real pressure so I can afford to explore a bit and give plenty of time to it’s development.

Thanks for any thoughts or feed in
Cheers
Graham

Tao, your questions come from reading too many forum post, and not one reference design you want to build to. A few points:

1. When you mull over Radian or BMS, or Lyra or VDH or Koetsu, or any A or B, when you are doing blind, you end up doing both. So these questions don't help unless you know one you want to get to. As you go deeper into the process, you will want to do more, including some vintage, some unobtanium, and some bargains that come up that you were not looking for previously. Radian is as good a driver as any I have heard, question always is if people like something different. Some like paper opposed to Be, for example, some like both. So you can choose different types of drivers (either you get Lyra Etna, Atlas, Etna SL, Atlas SL, or you get Lyra, Koetsu, Opus, etc).
2. If you want to use a 1.4 inch driver on a 2 inch iwata (or any other horn), you either need an adapter, or you can get the Radian 950 which is same as 951 with a 2 inch
3. For your big room, you first need in place a big design. Neither PAP nor Harbeth cut it, sorry. So you need to start afresh.
4. Regarding 2 way or multi-way and your point on coherence, I have heard single driver up to 5-ways. The most coherent are dual FLHs - the design just gets things right - the timing, integration (no hybrid stuff), and they sound point source too as long as you have like 4m from them. The bigger the room, the greater the FLH advantage. So it is just not about how many ways, it is the design too. You can also do BLH, Anima, Avaton, SLOB, or whatever, but you need to know what design you want to get to.
5. You can start 2-way, then add tweeter, then add subs. I don't know anyone, Cessaro included, who have been able to build a perfect 5-way - it does get too complex and that causes some lack of coherence as well as lack of ease in driving it.
6. 1 inch or 1.4/2 inch dilemma that you mentioned is more of small speaker/big speaker. With a 1 inch you will end up with a compromised bass like Onken.

 

[the sound of Tao]

Thanks Ked,
If I was going to do a reference design I’m not sure David would like me doing a bionor clone which was my first instinct .

I’m a bit stuck given current travel restrictions so happy to ballpark in initially. I’m seeing this as a journey even if I don’t leave the Covid lockdown perimeter. I’m not even expecting to get it right in one go. Given any auditions will cost me long term isolation (or if unlucky an early grave) I’m considering this as an investment in buying in the discovery.

I have heard beryllium type drivers though not the radian but feeling it’s a good starting point... though I’m tempted to also think wood horn will be the go as that is the one constant in horns that I have really connected with. So I may initially buy autotech but then if the horn shape is a good fit sonically I would do a custom wood horn and see if that suits better.

With you 100% on starting 2 way then trying the subs and if needed topping off with a separate tweeter. That said I have really enjoyed the paps top end and that starts rolling off at around 18k.

Had you decided if you are going to try out the TD4003s. Would love to hear a video when you get your dual flh happening either way. I was influenced by the horns in Germany that you reported on with the dual flh and autotech Iwatas... great look!!

I’ve loved all videos of the big horn setups from WE and like the idea of having one setup just for the big classical listening especially now as options for large scale live music are still dim and we won’t really have many options to get a fix that often except at home... certainly not a good time for the traveller or the live music lover

 

[bonzo75]

The TD 4003 videos will be of Leif's set up. If I wean myself off Netflix/prime I will finish the article and post it.

Generally the design is more important. For me, A dual FLH can be done with Altec, Radian, JBL or TAD, vitavox, Gauss. So dual FLH comes first, and the type of FLH design. Then the driver plus horn combo that suits that design and cross over requirement. Then you need to see what you can access and who can help you.

There are too many bad implementations of all the drivers. If you go to DIY forum or Lansing heritage you will get confused by driver A better than driver B. Most of them don't end up building a proper horn, they just keep building a new thing every month. It is the same madness as trying different cables or changing VTA. Maybe there are some really good ones there too, you will never know until you hear. So if you hear one and think it is as good as a sound you are ever going to get, that's your design. Otherwise you will be building forever. Which can be fun too

 

[the sound of Tao]

Much looking forward to the videos from Leifs, that’ll be a really interesting thing to watch.

I have been reading up a lot and I also get how much of a problematic skew that can put on things. I’d love to have heard more... it would help a lot. It’s easy to hear when things are just right.

I am however slow to decide and usually put in a few months after I’ve made up my mind purely as hesitation. It might be optimism but I strangely feel more OK with the unknown these days... it might be 2020 syndrome I think. Though I’m sure I’m not on my own in owning the uncertainty.

 

[kodomo]

A 4 or 5 way horn speaker is a really big undertaking just keep that in mind. Not just the drivers but also the crossover, the horns and the structure that holds it altogether are all important. Everything has to work really well together, you need to plan a lot, make small experiments and you will definetly need measurement equipment both electric and acoustic. Do not just go for trial and error, there are way too many variables to be able to make a complex design such as this without measurements. Then you also need a room so that you can be at least sitting as far as where the driver integration occurs. The multiway horns start sounding coherent from that point on, if you are closer it is not physically possible to have coherency because of the distance between acoustic centers. These distances etc are all have to be taken into account, like maybe a jmlc horn with 200hz cutoff is better suited for your planned bandwidth, however having also the midbass horn, and tweeter, upper mids in between, the jmlc would be too high tand wont give the response accordingly to plan...

A small and rough guide that you can work on may go like this;

20hz - 80hz - A bass solution you prefer, I very much prefer the OB servo bass array
80hz - 600hz - A dual FLH (rectangular mouth so as to gain space without loosing much else)
600hz - 5khz - JMLC cf 350hz - 2" cd
5khz - 10-12khz - JMLC cf 1400hz - 1"cd
10-12khz+ - Fostex t500amk2 or TAD ea703 or similar

This would be just the horns and drivers. Now, the crossover design is no simple matter and I would tell you to work with professionals and if you need I can give you some contacts for people who design multiway horn crossovers for a long time.

Then comes the structure, your drivers should be able to move and get adjusted along vertically and for depth. You will want to align them.

I can keep on going but I just want to remind you again that this is a very rewarding but a very big undertaking. I love my multiway installation but I never thought of it as a product like cessaro does, it is quite complicated. This was the reason for my new speaker design not being a 5 way horn. A 5 way is not home, wife and user friendly

 

[the sound of Tao]

That is awesome Kodomo, I think there is much wisdom going on there right through to the end. Some trepidation now included as well as feeling taking this on might be exactly what I need to keep the life force going forwards.

I would say that your small rough guide seems to me to be quite a very great help thank you.

A modular component based system with really well engineered adjustability in the structure sounds like a nice design element on its own.

The crossover design sounds like the part I have least capacity for and would be something I’ll definitely look to you for your references on.

I enjoyed upgrading my existing crossovers in both the Maggie 20.7s and the Paps but that was really just about upgrading parts using existing values.

I am feeling I could perhaps settle in for a longer journey with this. It feels like a renewal. All the advice is helping to bring something a bit more solid through on the vision even just now. I admit in design I enjoy the quiet darkness in the unknown where the ideas all form up from. This is starting to take some better shape for me, very much appreciated to all.

 

[bonzo75]

No horn is wife friendly. My gf says we came up with the term WAF just to pretend we are showing some consideration for our ladies to lessen our guilt

 

[the sound of Tao]

Guilt is good... oh no that was greed wasn’t it... though WAF = wishing alternative friendships

 

[kodomo]

No horn is wife friendly. My gf says we came up with the term WAF just to pretend we are showing some consideration for our ladies to lessen our guilt

On the other hand my wife loves our system and especially the horns. Not because they are big and bold but because they sound really good and has been built by me She is proud and talks about it too!

 

[bonzo75]

On the other hand my wife loves our system and especially the horns. Not because they are big and bold but because they sound really good and has been built by me She is proud and talks about it too!

Ok, that means she loves you and treats you like a baby where this hobby is concerned

 

[Audiophile Bill]

That is awesome Kodomo, I think there is much wisdom going on there right through to the end. Some trepidation now included as well as feeling taking this on might be exactly what I need to keep the life force going forwards.

I would say that your small rough guide seems to me to be quite a very great help thank you.

A modular component based system with really well engineered adjustability in the structure sounds like a nice design element on its own.

The crossover design sounds like the part I have least capacity for and would be something I’ll definitely look to you for your references on.

I enjoyed upgrading my existing crossovers in both the Maggie 20.7s and the Paps but that was really just about upgrading parts using existing values.

I am feeling I could perhaps settle in for a longer journey with this. It feels like a renewal. All the advice is helping to bring something a bit more solid through on the vision even just now. I admit in design I enjoy the quiet darkness in the unknown where the ideas all form up from. This is starting to take some better shape for me, very much appreciated to all.

Hi Graham,

Personally I wouldn’t go down the complex multi-way route as the first major build because it will be a very tough project and integrating all those horn channels will be very difficult indeed and also costly if it doesn’t work out (horns, drivers and plethora of crossover parts).

In terms of the above posts - I just wanted to clear something up. When people talk about dual woofer flh - there is the purist route (such as Leif’s) or the hybrid cabinet like the Altec 817, 211 etc. The latter produce reflex bass below their horn cut off, which is in reality around 80hz+ for say a 817. Below that, you effectively have normal reflex bass so are a hybrid solution. That is helpful if you want to simplify because then a 2 or 3 way is possible but also with less horns required - you effectively got 35-40hz to 500hz covered in that one cabinet.