Beyma CP21F match for Beyma TPL150H

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steve s
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#16 Re: Beyma CP21F match for Beyma TPL150H

Post by steve s »

Fair point gents re regarding a peaky response.. But that to me is very different to what I would term 'control' of a bass driver.

In John's case a 1st order may or may not be right.. But he'll learn alot whilst finding out.
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#17 Re: Beyma CP21F match for Beyma TPL150H

Post by JohnG »

I am not the one to defend my corner against any of the foreseen failings with the driver choices.
The constraints are being pointed out by time served builders, so I will take note.
I am not at present,in a place where I feel I should abandon a few drivers for a couple of say Fane 18XB's.
A Steve has said, the Beta's will be usable as a initial Driver.
I don't think I'll be wasting my time, but should learn something, if they are functioning ?

The Eminence are probably the weakest link for more reasons than just the performance constraints.
I won Five PA Speakers for £45 and as a result removed five Beta 15's before selling on the Cabinets for £20.
It would be a shame not to give them their chance, they might be duffers, or they might be the most run in
Beta 15's in use on Audio Talk, as the Vendor had the Waltzer Parked next to the Caravan.

A person has to start somewhere, and as my other Drivers being included are not being as scrutinised ,
I am feeling good that the initial assembly will start the ball rolling to a better end point.
Remember, I am a complete numpty when it comes to electronics, so when I use a term like First Order Xover,
I have it as a proposal, as it is a less complex design and build.
Nothing is ruled out, if the end point seems good enough to be worth pursuing.

I'll keep posting on the build, I'm sure it will be of interest for multiple reasons.
At the moment, I am seeking out a Adjustable Virtual Xover, just to get the ball rolling.
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Nick
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#18 Re: Beyma CP21F match for Beyma TPL150H

Post by Nick »

FWIW (not much) I am still using Beta 15's in the OB's here with a first order series xover.
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#19 Re: Beyma CP21F match for Beyma TPL150H

Post by JohnG »

That's encouraging Nick.
I also know your proud of these speakers and have offered to me the invite to listen to them.
The Beta 15's are a driver I was pointed to in the past on here, I remember it being praised for its VFM to performance.
As mine are super cheap as a purchase, if all are functioning, the smile factor will be part of the equation, I hope the Honeymoon
isn't short lived.
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#20 Re: Beyma CP21F match for Beyma TPL150H

Post by simon »

Don't be put off (we can see you aren't). Throw some stuff together on a board. Have a listen. Enjoy the fruits of you labour. Get used to it. Start to think about what you might not like about the sound, and what you do. Then think about how you might improve them. Listen to wise words but remember they're your ears not someone else's. That's the point of DIY, otherwise you might as well just buy something from a shop. Get stuck in, keep posting, and enjoy the ride.
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#21 Re: Beyma CP21F match for Beyma TPL150H

Post by JohnG »

Thank you Simon
I attached myself to Audio Talk because of the OB Content, and reinforced that experience by visiting Owston.
The intention has been rooted for many years, Audio Talk took the idea to achievable, as the amount of projects completed proved this.
I like the idea of adding one more to the Build Thread, and reporting on how it evolves.
The 12P80ND is a driver not referred to often, but the initial investigation of its measurements are already reported as useful.
I think Phil got the Ideal Bass Units to go with the Beyma's, I had my eye on it as well, but I was dithering, maybe later on we can see if they can be used to get the idea of of a different bass unit in the array.
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izzy wizzy
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#22 Re: Beyma CP21F match for Beyma TPL150H

Post by izzy wizzy »

There's also something to said for simple crossovers. Sure you can eq things to make them "flat" whatever that is but you can end up with throwing other enjoyable things away in the process.
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#23 Re: Beyma CP21F match for Beyma TPL150H

Post by chris661 »

Seems to me that a simple crossover might just work here. 15"s tend to get messy above 1kHz, but using a 12" mid will mean you can cross fairly low, so you can keep the upper-mid mess of the 15"s down. I'd probably aim for a 2nd-order lowpass to cut the mess down further, but that's something that can be experimented with.

The 12P80Nd to TPL150 crossover, IIRC, has been done a few times elsewhere, so it might be worth drawing inspiration from those that have done this before. I'd consider a minimum 2nd order highpass on the TPL, just to avoid too much LF signal getting in and damaging the driver.

Complex crossovers have their place when they're done to achieve something, and they can sound really good. The system I have at the moment uses about 16 components per speaker, but each one has a specific job to do.

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#24 Re: Beyma CP21F match for Beyma TPL150H

Post by ed »

I'm not sure whether this is relevant but this is what I did back in the day. I messed with 1st order in a naive fashion(cos I didn't know any better) and ended up with something like this.
beyma ob.jpg
It's not simple but clio said it was spot on. I can't remember what it's all about(I do have notes if anybody is interested) but I did get it from Andrea Cuiffoli. He used to have a well written description on his website but I'm not sure if it's still available.
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#25 Re: Beyma CP21F match for Beyma TPL150H

Post by Scottmoose »

Well, referring to the diagram:

-The shunt LCR (4.7mH, 23.2uF, 25ohm) across the terminals is to flatten the impedance rise at / near the crossover frequency which will make life easier for high output impedance amplifiers & reduce the tendency for them to modify the response in line with the impedance curve.

High Pass (TPL150H):
-The 3.3ohm resistor shunted by a 3.3uF capacitor is level padding; however, by shunting the resistor with a cap you reduce the attenuation in the higher frequency range

-The 20uF series cap (2x10uF in parallel) & the 0.82mH shunt inductor provide a 2nd order electrical high pass. What the acoustical order is I don't know without back-engineering from the on-baffle response, but I suspect closer to 4th order.

Low pass (SM115N)
-The 2.7mH series inductor and the 15uF + 1.8ohm [nearly] resistor form a damped 2nd order electrical low pass. The latter is possibly also acting as a partial Zobel / Boucherot cell for flattening the rising VC impedance and allowing the series inductor to re-shape the response consistently. Without reverse engineering, not sure which; there is usually a reasonable amount of 'crossover' (no pun intended) in these cases -the Ariel low-pass is a good example of that also. Again, don't know what the acoustical slope is without back engineering the on-baffle response; I suspect it would be lurking around a 2nd - 3rd order slope to get good phase alignment with the TPL around the crossover frequency.

For whatever it's worth (nothing) re this baffle business, I would suggest that if single-element electrical filters are required for xyz reason, then a series rather than a parallel type is preferable, as Nick uses, and as the Quasar uses / used. Single-element (per driver, not including any padding resistors) series 1st order has some interesting properties not shared by any other crossover type. Electrically speaking, the drivers are locked together; all components are always in circuit at all times, and while it maintains 1st order characteristics, when the bass driver's inductance reaches a certain point, the acoustic rolloff starts to transition to a quasi 2nd order slope, which can be useful when you need to shunt some unwanted resonances out of the way.

Now back to lurking [very] far in the background.
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#26 Re: Beyma CP21F match for Beyma TPL150H

Post by JohnG »

The types of technical description offered are above my understanding.
For me they are another advisory to be presented to those who will assist with producing the Crossover.
I have been offered the chance to put the Beyma Drivers onto a Vidsonix Crossover to get the initial feel, and revisit the Bass, when a Xover is identified as usable.
It is a good start, if all goes to plan the Beyma drivers will be with me in a few days.
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#27 Re: Beyma CP21F match for Beyma TPL150H

Post by chris661 »

Which bits are you struggling with? There are lots of terms there that would further your knowledge with a bit of looking around online.

No offense intended, but your response comes across as rather ungrateful.

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#28 Re: Beyma CP21F match for Beyma TPL150H

Post by JohnG »

There is no Gratitude amiss at this end.
All thoughts/contributions in any measure being expressed on the build are being very well received.

I have a friend who lives local, who has worked on Xovers and Built a few of their own speakers.
This person is fluent on the speaker design subject and fortunately they are happy to offer their time to help with the
Xover.
Their initial request was for me to see if I could acquire a Schematic to help identify another builders choice for a Xover
when a combination of the Beyma's have been used.
It was stated that due to the cost for the Xover Components to work on the Bass, this would be introduced later, when the requirement is better understood.
The Bass may become its own independent build, so that it could be used to work with the ESL 57's.
It will have to be worked out if this will be a further compromise on the performance of the OB.
In the meantime, I have a offer to help build a Xover, combined with a offer to receive a training session with a Computer Software and Microphone to help set up the parameters for the Xover.
From another forum where a Schematic request is made, I now have a few web sites to read up on Xovers.
I would like to think, with the three sources of support, I will come out the other side a little more savvy, with a OB producing sounds.
As a update, I received a Text on Saturday morning, from the Vendor in Newcastle to inform me the drivers are now picked up 8)
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#29 Re: Beyma CP21F match for Beyma TPL150H

Post by ed »

Scottmoose wrote: Thu Nov 28, 2019 12:54 pm
High Pass (TPL150H):

-The 20uF series cap (2x10uF in parallel) & the 0.82mH shunt inductor provide a 2nd order electrical high pass. What the acoustical order is I don't know without back-engineering from the on-baffle response, but I suspect closer to 4th order.

Low pass (SM115N)

Without reverse engineering, not sure which; there is usually a reasonable amount of 'crossover' (no pun intended) in these cases -the Ariel low-pass is a good example of that also. Again, don't know what the acoustical slope is without back engineering the on-baffle response; I suspect it would be lurking around a 2nd - 3rd order slope to get good phase alignment with the TPL around the crossover frequency.
This may or may not be useful to John, or his fluent friend, but this is what Scott was alluding to:
both.jpg
apologies it looks a bit rushed with all the room interactions but it shows the gist.....
be aware this is not the finished response, it is merely 2 recordings superimposed.
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#30 Re: Beyma CP21F match for Beyma TPL150H

Post by Scottmoose »

Cheers for that Ed, I thought as much: roughly 4th order high pass acoustic slope, about a 2nd order low pass acoustic slope. Quite a common alignment, usually to get the phase lined up around the crossover frequency. Basically an asymmetric LR4.
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