Arvo "Classic" Build

[bratislav]

That was quick ! Thank you very much . I'm a bit more confident now that replacing the woofers isn't going to mess up with M8a part. And I can always use full eq (DEQ2496) to "massage" the woofers into the shape I need them... But I will try to do that first via analog crossover Jon suggested.

Back to the drawing board ...

[cjd]

Ahh. How heart-warming it is to see a true DIY spirit at work.

er...

hmm, I think I need my morning coffee! Too smarmy and sappy, not enough sharp ironic (with a touch of sarcasm) wit.

C

[JonMarsh]

It's not really 8dB boost unless you measure from the bottom of the 500 notch. More like 4-5dB from the 850 Hz level. Jon's gets by without all that by a combination of a wider baffle, asymmetric mid placement and a higher cross to the woofers. The asymmetric mids avoid the notch at 500. The wider baffle lowers the frequency where the dipole boost starts a bit and the higher XO reduces the total dipole boost needed. Crossing 2/3 octave higher buys you 4dB less boost on the mids so it all works out.

Thanks Dennis! :T you've been paying a lot more attention than I realized!

I prefer acoustic solutions to acoustical problems when possible.

[bratislav]

Too smarmy and sappy, not enough sharp ironic (with a touch of sarcasm) wit.

C

Put it this way - I can get Peerless XLS (or XXLS) for 2/3 of what 315HF would cost me here. How's that for sarcasm? 8)
Or would that be a tragedy ? Hmmm ... time to brush up on old greek ! :roll:

[cjd]

I was talking about *myself* but hey.

The word you're looking for is "pity" - it's a pity the Daytons cost that much. Take what you're dealt and do what you can. The Peerless are no slouch either. May be other options too. Look at the driver parameters you seek rather than brands, perhaps. Pro-audio gear may have an answer...

C

[bratislav]

I was talking about *myself* but hey.

The word you're looking for is "pity" - it's a pity the Daytons cost that much. Take what you're dealt and do what you can. The Peerless are no slouch either. May be other options too. Look at the driver parameters you seek rather than brands, perhaps. Pro-audio gear may have an answer...

C

Not sure "pity" has Greek origin :B
There is one (good) reason for me to stick with "names" - no-names often have wildly different parameters from what is on the box. I'd rather get a cheap-ish Peerless (SLS) than a fancy looking "house" name (rebadged Chinese generic clone).
Pro drivers tend to have highish resonant frequency and very little Xmax. On the plus side they tend to be very efficient, low distortion, ultra high SPL capability and reliability "hi-fi" stuff can only dream of. Not quite sure pluses outweigh the negatives in my case.
Found several implementations of SLS in open baffle arrangement on the net.
High-ish Le, but XLS isn't much better either in that respect.

[JimS]

Sorry, I somehow missed the part where you said you had used the TBL before. I'm not trying to talk down to you. I just blacked out in that part of your last post. :roll:

Backwards (or maybe sideways) progress . . . you would think I would pay more attention since I've done this finish before :roll:

Lots of sanding and three light coats of primer is NOT enough to cover flaws in MDF and BB edges despite it looking and feeling smooth . . . finished 4th coat of textured paint last night and decided it's not quite covering remaining flaws in the finish . . . so started another round of sanding, primer, and more sanding . . . did I mention nice finishes are a PITA?!?!?

maybe by this weekend

[JonMarsh]

Yes, they are a PITA, but that's where the pride comes in, knowing you've done the work, walked the talk. :T

[soho54]

Sorry I jinxed you. :cry:

The easy way to check before putting on the TBL is to use flat black as the last coat, and then snap a picture of it from several angles with a digital camera with the flash on in soft back lighting.

Another way is to use a gloss/semi gloss black paint to check for problem areas. This way you don't have to waste all the more expensive TBL, and saves the elbow when sanding it down.

Water will work somewhat too. :B

Good luck.

[JimS]

Slow progress

[JonMarsh]

slow progress

When it comes to speaker projects, Jim, I don't think there's any other kind of progress! But it looks like you're definitely making some!

I just got back from Singapore, and I'm making a little progress today, too. Nothing I can post, but tomorrow, maybe so!

Jon

[soho54]

After staring at mine for the last year the inverted color scheme is messing with my head. :B

Looking good.

[soho54]

One thing make sure you know how you are going to wire things up before you finish the trim work. You don't want to end up cutting holes after the fact, and have to redo some of it.

Ask me how I know... ops:

[JimS]

One thing make sure you know how you are going to wire things up before you finish the trim work. You don't want to end up cutting holes after the fact, and have to redo some of it.

Ask me how I know... ops:

Already done :T will be routed through the base to binding posts in back (which dry fit nicely, at least before the textured paint was added . . .) thanks to Paul & you for the idea!!

got the tweeters & M8As installed tonight & they look really good (photos don't do them justice - especially when I have to crop & compress them to <100KB) - can't wait to find some time to get the crossovers wired up and make some noise . . . :B

[JimS]

quick double check before wiring cabs . . .

M8As are series wired in this version, correct?

[JonMarsh]

Yes! In all versions.

[JimS]

Cabs done and one wired up

got the LP and zobel done . . . still need some dabs of hot glue and still need to layout the HP

sorry for the slightly blurry pics (either too much or not enough coffee - haven't figured out which yet . . .)

[chasw98]

Looking very good there Jim! :T
I am hot on your heels. I have just finished assembling the cabinet for my second one and am getting ready to load up the drivers. Keep going!

Chuck

[ThomasW]

Gee, all of a sudden there's a flurry of new Arvo activity... :B

[JimS]

Looking very good there Jim! :T
I am hot on your heels. I have just finished assembling the cabinet for my second one and am getting ready to load up the drivers. Keep going!

Chuck

Chuck - yours are looking good as well :T

I'd be willing to bet you'll pull ahead this weekend . . . off to a soccer game now (son's), golf tournament (me) this afternoon, tomorrow is baseball (daughter) and hockey tournament (son) . . . sleep is overrated :Z

[chasw98]

quick double check before wiring cabs . . .

M8As are series wired in this version, correct?

Yes! In all versions.

Jon, why are the M8A's wired in series? Not questioning, just want to understand the reason behind it. The LF drivers are in parallel, correct?

Chuck

[JimS]

Jon, why are the M8A's wired in series? Not questioning, just want to understand the reason behind it. The LF drivers are in parallel, correct?

Chuck

For LF I'm using series for an 8 ohm load on the amp (since I've got the 4 ohm versions), yours (the 8 ohm versions) would be parallel for a 4 ohm load.

[Brian Bunge]

Chuck,

I imagine it was to keep the efficiency down so that the LF drivers could mate properly. Chris did that very thing with my big 3-ways. The dual RS180's in parallel were too efficient in parallel to work with the dual RS270's. So he wired the RS180's in series.

At least that is my understanding of why this was done.

[ThomasW]

Jon, why are the M8A's wired in series? Not questioning, just want to understand the reason behind it. The LF drivers are in parallel, correct?

Chuck

Yes just the 12"s, and doing so lowers the distortion just a bit.

[chasw98]

I have the 12's in parallel for a 4 ohm load and have tried the M8A mids in both series and parallel. They were rather efficient in parallel.

[JonMarsh]

Jon, why are the M8A's wired in series? Not questioning, just want to understand the reason behind it. The LF drivers are in parallel, correct?

Chuck

Two reasons-

1. In comparison to the LF drivers, we don't need the increased voltage sensitivity that wiring in parallel would bring-

2. In series, the load impedance is higher, and with the crossover, the net impedance on the amplifier is more benign. Although most Arvo Parts have been built with people biamplifying them, my first version was an all passive design, and this was a way to help balance the sensitivity without using LPADs wasting power.

[chasw98]

Thanks, Jon. In other words a free pad that helps balance the levels between lo, mid, and hi.