First speakers, sorta done! Huge thanks to Paul Carmody! What next?

[mlau]

Smarties that know waaaay more about this stuff for me.
I'm just glad to find a more doable hobby than building guitars.
Also, it's very fun to choose veneers as my palette....ash, oak, wenge, mahogany, koa, rosewood, etc.

I might go with C-notes (for my friend, or my sister) or Classix 2 (for myself, recommended by Paul).

Currently, I'm trying to limit my spending.
I need to finish some guitars and ukuleles that I owe to friends/clients/etc.

[mlau]

This stuff is waaaaaay over my head!

That's why I appreciate guys like Paul, Jeff, Wolf, and all you other S

[Millstonemike]

Thanks.

Am planning on using the DC160-8 with a TPA3116d2 based mono amp rated at 100W RMS for a 4 ohm load and 50W RMS for a 8 ohm load with a 24V power supply.

Those ratings are incorrect.

First off, at 24 V (or the max 26 V rating of the amp), you can't get 100 W rms into 4 ohms or 50 W rms into 8 ohms.

The typical 100 W rms rating for a TPA3116 chip is with both channels operating in PBTL mode (e.g., paralleled) into 2 ohms. That would generate some 140 W buts the 100 W rating is the thermal limitation for the entire chip. The 2 X 50 W rating is each channel powering separate 4 ohm drivers while keeping to the 100 W thermal limitation of the chip.

The mono TPA3116s amps are in PBTL mode so each module has a thermal limitation of 100 W. The power output for a sine wave is defined by

P rms = (V_ps² / 2) / R = (24² / 2 ) / 8 ohms = 36 W rms. In reality there are semiconductor voltage losses in the chip so you looking at ~32 W rms into the DC160-8.

[Geoff Millar]

If you have a "small" setting on your amp, you could do that, which would limit low frequencies. But that's kind of spoiling the fun, because the DC160 loves playing low. It sings down there. Granted, it can't go super-loud, but it's only a 2-way bookshelf, so it wasn't going to be that loud to begin with.

I wouldn't worry about it.

Maybe the Classix 2.5 would be a solution here!\

Geoff

[Paul Carmody]

Hi,

The crossover point is 2.5KHz in the Classix II project. Effectively, a LP of 2.5KHz for the Woofer and HP of 2.5KHz for the Tweeter. So, the Tweeter gets protected at its lower Frequency Range. What about the protection for the Woofer for its lower Frequency Range / limits? What are its limits to avoid cone excursion issues.

If you have a "small" setting on your amp, you could do that, which would limit low frequencies. But that's kind of spoiling the fun, because the DC160 loves playing low. It sings down there. Granted, it can't go super-loud, but it's only a 2-way bookshelf, so it wasn't going to be that loud to begin with.

I wouldn't worry about it.

[bsl100]

Thanks.

Am planning on using the DC160-8 with a TPA3116d2 based mono amp rated at 100W RMS for a 4 ohm load and 50W RMS for a 8 ohm load with a 24V power supply. Will use a trimpot to ensure that the signal will not exceed 50W RMS and keep the signal clean (<0.1% THD). Am planning a RC high pass with a 12db slope on the amp itself to protect the woofer cone from bottoming out.

The enclosure is 15L and am planning on using a single 2" dual flared port tuning the box to around 45Hz.

[scottvalentin]

Typically protecting the woofer from excursion issues by using a high pass is done on the amplifier side (sometimes) and not in the crossover. As Geoff mentions above, cabinet tuning and size play an important role as well.

[Geoff Millar]

Hello

That's beyond my knowledge/expertise, I'm sorry. I expect the answer is something along the lines of the cabinet size and power handling capacity of the woofer, plus the listening volume and characteristics of the source material.

I'm sure the more experienced and technically-minded members will be able to advise you.


Geoff

[bsl100]

Hi,

The crossover point is 2.5KHz in the Classix II project. Effectively, a LP of 2.5KHz for the Woofer and HP of 2.5KHz for the Tweeter. So, the Tweeter gets protected at its lower Frequency Range. What about the protection for the Woofer for its lower Frequency Range / limits? What are its limits to avoid cone excursion issues.

[Geoff Millar]

Hello

Not quite sure what you mean in your question: the Classix II are two way speakers and there are high pass (tweeter) and low pass (woofer) filters in the crossover: the circuit diagram is on Mr Carmody's website and in the PE product manual.

The thinking behind the crossover is outlined in the Paul's description of the speakers' design.

Some older and cheaper crossovers (like the one in my Interdyn Pee Wee speakers!) only have a capacitor and a resistor to protect the tweeter and the woofer is allowed to do its own thing. The crossover in the Classix II uses a 'second order' crossover, i.e. two main parts: an inductor and a capacitor.

I was a complete soldering novice but found the crossover easy to put together.

Is this the sort of information you're after?

Geoff

[bsl100]

Is there any High Pass Filter used for the DC160-8 5.5" woofer in the CLassix II build?

[griffin443]

Congrats, they look great ! None of us are perfect. I know they sound great too. Enjoy and keep building.

[mlau]

Here's the pictures. Lighting isn't perfect. Camera is my phone. veneer work wasn't perfect (baffle was slightly proud). Finish wasn't perfect.

However, I think there are pretty stinking nice...and I'm satisfied.
The crossovers were a pain in the rear to solder to the PCB board--took me 8 tries! but I learned a ton.

Finish is freshly mixed Kusmi garnet shellac. Probably 200 weight. Hand scraped finish--pretty minimal sanding
Wenge baffles and front border. Mahogany for back and sides. Felt right.
Nilfisk Attix 8 hidden in closet...great vac.

Btw, fun fact--- I ran into Ervin Somogyi at the wood store when I bought the veneers.
He thought the speakers would look great naked, but I told him it was for a friend.

-Matt

ps. It sounds silly, but one reason I want to build more speakers is to see how much nicer the finish/veneers will be on the next one!

[mlau]

Thanks for the suggestions!

I might look into the Classix II. It's just that the GR Research X-LS has been on my lust list for a while.
Too bad, I can't demo them.

oh, and Paul. Check your email.

[Whitneyville1]

Matt, congratulations on your first builds! I have three sets of "bookshelf monitor" speakers, and I listen to the ClassixII's the most. For strictly music, unless you're a bass head, you really don't need a sub-woofer with the ClassixII's, and they are great for "modestly presented" music like Pandora, Spotify, iffy CD's, LP's or MP-3's. Monitors with really detailed mids (The "Veepers") can be very unforgiving of not-so-good music sources. But this is the super thing about DIY speakers: You can build for a type of music and music source. Enjoy yourself!