Another Arvo Pärt MKII.V Build

[seattle_ice]

I have 4 of the HiVi M8a's and a couple of the rs28a's laying around as leftovers from another project. I decided I would really like to experiment with something different than box speakers for my next project. So the project I have decided on is the Arvo Mk 2.5, the one with the tapered baffle and the above speakers with the TC2+.

I also have a Cinenova Grande that I will be using to drive them with.

I have some questions, though, that I would appreciate some help with.

1. How much would it affect them to slightly arch the top of the baffle?

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2. It seems the TC2+ DVC is not available anymore. Will the SVC be suitable? I understand it might not be a perfect fit as is, but it looks close.

3. Can someone explain this crossover in a little more detail? Which drivers are which? I can guess, based on the size of the inductors, but I want to be 100% positive. Which parts are really necessary to use the good stuff on? I have a couple North Creek 12awg inductors laying around that I will use, but any advice as to where money should be spent, and where it is not so critical will be appreciated. And are the mids and woofers wired in series?

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Thanks. I am really looking forward to hearing what all the fuss is about with Dipole speakers. Plus it is fun to build stuff.

Darryn

[soho54]

D1 Woofer-series
D3 Mid-series
D5 Tweeter

[seattle_ice]

D1 Woofer-series
D3 Mid-series
D5 Tweeter

That is what I thought, just wanted to be sure. Thanks.

[soho54]

Use the good stuff for parts in series with the drivers. The entire tweeter portion if possible, especially L2.

The woofer section will have to be tweaked for the SVCs.

[soho54]

That is a 5 channel amp right? Have you thought about running the woofer section actively? It would get rid of the hassle of working out a new passive crossover for the low end.

[BobEllis]

Going active isn't quite as simple as dialing in an LR4 at 125 Hz. Although you no longer have to deal with changing driver impedance with frequency, you still have to apply some EQ for the open baffle and driver FR irregularities. If Jon published the transfer curves it shouldn't be hard to make an active filter with the appropriate response.

If you want to go active and make your own filters, I have boards that can handle the filter and EQ. PM me for details.

[ThomasW]

If you have a generic active LR4 crossover and some form of active EQ (Behringer BFD, etc.), that setup can be used for the woofer to MTM XO point.

That's how I've been running my Arvos since they were first constructed and it works fine.

[JoshK]

I plan to biamp my arvo part variation. I might actually get to building them this summer too. :lol: A bitch of a professional exam, a bathroom complete gut/remodel and central heating/air (all doing myself) have kept me from getting started. The lonely drivers are just sitting on my shelf begging to used.

[JoshK]

by the way, I like the arch look. I thought of doing that too.

[seattle_ice]

The Amp I have is a three channel (300wpc@8ohm/600wpc@4ohm) version.

If I really need to bi-amp, I will pursue getting another one. I would prefer not, but hey, it is what it is.

[soho54]

You don't have to bi-amp, if you had the five channel version it would have cost about the same amount to go active since you didn't have to buy another amp, and you wouldn't have to redo the woofer passive crossover section. Since you only have a 3 channel amp might as well go all passive. no need to buy another amp. I was just thowing options out there.

[soho54]

1. How much would it affect them to slightly arch the top of the baffle?

This is what Jon has said about rounded corners in the Heavy Metal thread,

The problem with arc boundaries roughly equi-distant from drivers is that they concentrate baffle boundary effects at one frequency, and the frequency response of the driver on the baffle is less smooth.

Not a stern never, no way, but be aware it could have audible effects.

[seattle_ice]

The problem with arc boundaries roughly equi-distant from drivers is that they concentrate baffle boundary effects at one frequency, and the frequency response of the driver on the baffle is less smooth.

I understand that, I was more asking for the severity of the effect in relationship to a minor arc such as I have drawn. I was hoping someone could model it. I can always try it and measure the effect, and cut it flat if it bothers me.

[seattle_ice]

What size inductors should be used in the various spots? I know Jon is always going on about the North Creek 12awg jobbies, but they are pretty pricey.

[ThomasW]

The 14 gauge perfect lay are good.

[Eric S]

2. It seems the TC2+ DVC is not available anymore. Will the SVC be suitable? I understand it might not be a perfect fit as is, but it looks close.

I just contacted Todd at OAudio and there is but a single SVC TC2+ driver available and none of the DVC. There are no plans to restock the driver.

Any suggestions on where to get this driver? I found a guy on e-bay who has some that are new, but the parameters don't match what is on the OAudio web page. I suppose they are very old - looks like they have a foam surround in his photos

Is the Hi-Vi M-12 still a suitable replacement? Adire's DPL12?

Guess I've been fence-sitting for too long again!

Any help would be appreciated!
Thanks!
Eric

[soho54]

Dayton RS 12" HF.

That sucks about the SVCs. I had a few applications in mind for that driver. Oh well...

[Eric S]

Looks like this is the one from the "Testing 1, 2, 3" thread: DAYTON RSS315HF-4 12" HIGH FIDELITY SUBWOOFER ?

Then I have 2 more questions: What crossover changes are necessary and will there be a center channel design for these? I am planning on using them in my dedicated theater for the front array and a 4 foot tall tower will be problematic with the projector...

Eric

[ThomasW]

If you use a active crossover and EQ, you can drop in almost any woofers.

Don't hold your breath for any passive crossover updates or new speaker designs. Jon's life is now 60+hr work weeks and tons of travel. He doesn't have time to post to the forum, so he doesn't have the time to develop audio projects.

[Eric S]

I was thinking that I haven't seen as much from Jon lately - that's a shame to hear work is consuming all of his time. Thanks for the update, Thomas!

[WillyD]

Don't hold your breath for any passive crossover updates or new speaker designs. Jon's life is now 60+hr work weeks and tons of travel. He doesn't have time to post to the forum, so he doesn't have the time to develop audio projects.

:cry:

[soho54]

Looks like this is the one from the "Testing 1, 2, 3" thread: DAYTON RSS315HF-4 12" HIGH FIDELITY SUBWOOFER ?

Correct. :T

What crossover changes are necessary and will there be a center channel design for these? I am planning on using them in my dedicated theater for the front array and a 4 foot tall tower will be problematic with the projector...

I am planning on building a center later on. Using the same tweet/mid passive crossover and only one 12"woofer with a modified crossover. It's coming in around 36-40" right now depending on the slope of the baffle. I plan on covering the front with felt and cloth so it doesn't look like I have two left speakers up there. :B

That is, if I don't just get the MMG-W center and surrounds.

[Dennis H]

The TC-1000 drivers, available directly from TC Sounds, are basically the same thing as the TC2+ drivers O-Audio was selling, although they cost a few bucks more and the TS parameters may be different.

http://www.tcsounds.com/tc1000.htm

[ThomasW]

Those wanting a Arvo center could build the MTM with flanking woofers using the existing crossover for the MTM section and an active XO for the woofers. That's what I plan to do after the Maggie projects are done.

[seattle_ice]

The TC-1000 drivers, available directly from TC Sounds, are basically the same thing as the TC2+ drivers O-Audio was selling, although they cost a few bucks more and the TS parameters may be different.

http://www.tcsounds.com/tc1000.htm

According to the literature at TCSounds the TC-1000 uses the TC2+ motor with a copper shorting ring added. The specs are similar, although not exactly the same.

[Dennis H]

Thomas, is the passive MTM crossover for your active/passive version posted anywhere? Is it as simple as just deleting the highpass part of the mid crossover (probably not)?

[ThomasW]

The XO is designed is modular.

[Dennis H]

Hmmm..... so you're keeping the highpass on the mid drivers which rolls off the low frequencies? Are you also running the mid section through the active crossover? Maybe I'm overthinking this but it seems like you've got two separate circuits - one active, one passive - rolling off the lows on the mid drivers.

[soho54]

Maybe I'm overthinking this but it seems like you've got two separate circuits - one active, one passive - rolling off the lows on the mid drivers.

A simple y-adapter would remedy this. If one had aversion to it. Send full range to the MTM with one end, and run the second end through the active crossover to the woofers. Select a 4th order lowpass at the right freq and you're done.

Well, almost done. Still need to address EQ.

[ThomasW]

Yep mine's a kluge. I XO the woofers actively, then send the high out to the passive for the MTM. In spite of this they sound great.

[Dennis H]

then send the high out to the passive for the MTM

Okay, I think I've got it. Just to be sure, you're hooking the high output of the active crossover to the MTM amp, right?

[ThomasW]

Yep....

[seattle_ice]

I found a guy on e-bay who has some that are new, but the parameters don't match what is on the OAudio web page.

I saw those also, and was wondering the same thing. They are the SVC model also.

[ThomasW]

Follow up for Dennis H,

Been a while since I checked the Arvo XO. When Jon and I built the XO we disconnected the low filter part on the MTM section. So it's not the kludge I imagined...

[Eric S]

OK, It seems that there are several options for completing the Avros. As usual, I don't have all of the necessary knowledge to make informed decisions among them, so I am hoping you guys can provide some advice for me :B

The TC1000 driver looks VERY close in specs to the TC2+ driver, however, I have found other TC2+ drivers with a different set of specs. This all raises the issue of what are the specs for the TC2+ driver used in this design?

Back in 2004, I downloaded a PDF file from OAudio about the TC2+ with these spec:TC2+ Specs 2004. These are the specs that match what the fellow on E-Bay is selling.

Then, there are a different set of specs on the OAudio web site July 2006 Specs.

So, my first question is which specs are appropriate to the passive XO that appears in the top of this thread?

The specs indicated for the TC-1000 driver over at the TC-Sounds Web Page come very close to the specs for the TC2+ DVC on the OAudio web page. It seems that this would almost be a drop in replacement, but at a cost of $225 each.

If I go with the RS315HF from Parts Express, it looks like I would need an active XO (which I know nothing about...). Is using an active XO as easy as set the XO point, set the slope and work out the equalization?

The TC-1000 is priced about $100 more than the RS315HF. Would it end up being less expensive to just purchase 6 TC-1000's ($1350), or purchasing 6 RS315's ($650) and then buying 3 active XO's, and needing extra amps?

So, now that I am beginning to ramble, my questions are:
1) what are the specs for the appropriate TC2+ driver to use?
2) Is the TC-1000 a "close enough" direct replacement for the TC2+ as spec'd on the OAudio page?
3) would it be cheaper to use RX315's with active XOs than to buy 6 TC-1000s?

Thanks for the help! I've been hanging around for a years, but still consider myself a noob :baby:

Eric

[soho54]

1) what are the specs for the appropriate TC2+ driver to use?

The Oaudio TC2+ DVC is the correct driver, it was custom made for OA. It's specs are on the Oaudio site. The problem is the specs are with both voice coils in use. Jon has stated the OA TC2+ DVC with one coil in use is pretty close to the RS 12". The graphs are on page 12 of the HM thread I think.

2) Is the TC-1000 a "close enough" direct replacement for the TC2+ as spec'd on the OAudio page?

No, would be my guess.

3) would it be cheaper to use RX315's with active XOs than to buy 6 TC-1000s?

Depends on the active crossover, EQ, and amp costs. Why six drivers?

[Eric S]

Why six drivers?

Left, Center, Right...

I'm thinking that I'd prefer to keep the speakers more simple and not have to use active XO since I'm also currently building 3 Class A amps (150w into 4 ohms) to drive the front speaker array. But, if I can't find any original TC2+ drivers, it looks like I will have to go the active route. :M

Going active would mean 3 active XOs, and three MORE amps :E Any suggestions on capable active XOs?

By the way, the RS 12" are on sale this week for $100@ (makes it mighty tempting...)

[derekbannatyne]

Left, Center, Right...

I'm thinking that I'd prefer to keep the speakers more simple and not have to use active XO since I'm also currently building 3 Class A amps (150w into 4 ohms) to drive the front speaker array. But, if I can't find any original TC2+ drivers, it looks like I will have to go the active route. :M

Going active would mean 3 active XOs, and three MORE amps :E Any suggestions on capable active XOs?

By the way, the RS 12" are on sale this week for $100@ (makes it mighty tempting...)

Only for another 3 1/2 hours...

[Eric S]

While we are on the topic, what is the appropriate cross over point to the 12" woofers and what order is the XO?

[soho54]

Going active would mean 3 active XOs, and three MORE amps

Just get two stereo crossovers and two stereo amps. Keep the good stuff powering the MTMs.

Passive can be made to work with the RS 12", if you can measure the speakers in the baffle. Since the woofer section is crossed so low it wouldn't be to hard. Just use the same crossover layout and play with the numbers until the FR matches Jons. You should be able to get an 80% match pretty easily.

[soho54]

While we are on the topic, what is the appropriate cross over point to the 12" woofers and what order is the XO?

The passive lowpass is around 200hz with a 4th Order roll-off. You will also want to boost the <60hz signal with the EQ to taste.

[ThomasW]

The original Arvo passive crossover is specific to the DVC-TC2+ from Oaudio, and no this is not a stock TC2+.

This is an expensive passive crossover if properly built.

My guess is that eliminating the woofer section entirely, and removing the high pass section of the MTM, one would come surprisingly close to paying for the electronics.

Using a active XO like the Behringer CX2310 and something like the Behringer A-500 amp to power the woofers would work fine. I use the CX2310 for my Arvo's

So my suggestion is get whatever 12" drivers you like and go active. The RS315 are a good choice in this situation.

[soho54]

This is an expensive passive crossover if properly built.

This is an understatement. :B

[Eric S]

This is an expensive passive crossover if properly built.

Thomas, do you recommend Northcreek's method of bypassing capacitors to reach the desired values?

Looks like making a 200uF cap for the tweeter takes quite a number of caps. Is it appropriate to use "less expensive" larger caps and gradually move to more expensive ones as the smaller values are needed as bypassing reaches the desired end value? Say, maybe using a mix of larger value Auricaps, middle value Sonicaps, and then small value Thetas?

It looks like passive XO parts will quickly become many multiples of raw driver cost...

Thanks,
Eric

[soho54]

Looks like making a 200uF cap for the tweeter takes quite a number of caps.

Are you talking about the woofer? The biggest in the tweet is around 68.