High sensitivity soundbar project

[augerpro]

Unfortunately, that will take up too much space (if I understand you correctly).
I was hoping the short distance too the floor would help some with BSC.

You are placing a TV on the stand, correct? I'm just saying integrate this fact in to your design.

 

[ScottG]

What XO were you thinking of here?

..well if it was analog - probably just elliptical near 1 kHz with the Aurum Cantus.



HOWEVER I'd personally do it more like this:

miniDSP Kits : miniDSP 2x4 kit

2-way with the Liberty 8, ditch the Aurum Cantus.

Get the low-pass right on the 8 with the preferred amplifier, THEN

-use a cheap (yet good) digital amp with enough power for the treble section.

Then use an array of these (eq'ed and phase-shifted as needed) in a 1st order high-pass:

Peerless by Tymphany TC5FB00-08 1-1/2" Paper Cone Full-Range Driver 8 Ohm

http://feleppa.com.au/pics/speaker_imgs/plots/TC5FB0008_FreqResp.png

http://feleppa.com.au/pics/speaker_imgs/plots/TC5FB0008_RawHarm.png

-this way I'm not concerned with efficiency for the treble response and I can now focus on other aspects of sound.

 

[Defo]

You are placing a TV on the stand, correct? I'm just saying integrate this fact in to your design.

I'm actually going to use this Ikea TV bracket mounted to the center of the speaker/soundbar.
It mounts to the top and bottom of the enclosure with a height of 324 mm.
Hence why that height is set in stone

..well if it was analog - probably just elliptical near 1 kHz with the Aurum Cantus.



HOWEVER I'd personally do it more like this:

miniDSP Kits : miniDSP 2x4 kit

2-way with the Liberty 8, ditch the Aurum Cantus.

Get the low-pass right on the 8 with the preferred amplifier, THEN

-use a cheap (yet good) digital amp with enough power for the treble section.

Then use an array of these (eq'ed and phase-shifted as needed) in a 1st order high-pass:

Peerless by Tymphany TC5FB00-08 1-1/2" Paper Cone Full-Range Driver 8 Ohm

http://feleppa.com.au/pics/speaker_imgs/plots/TC5FB0008_FreqResp.png

http://feleppa.com.au/pics/speaker_imgs/plots/TC5FB0008_RawHarm.png

-this way I'm not concerned with efficiency for the treble response and I can now focus on other aspects of sound.

Sounds like a cool build!
However, I would prefer to keep the whole thing simple with a passive XO and a single amp.
I reckon getting that line array to work properly is out of my league.

Any thoughts on:

I've played with the thought of going 2.5 way with two Seas CA22RNY.
I could offset the rising response with that second driver, netting ~94 db sensitivity.

And then cross that to something like the Morel CAT 378.
Should be able to do that with nice shallow slopes

?

 

[ScottG]

Potential (likely) comb filtering problems with the double Seas and a high enough crossover for the Morel.

MOREL CAT 378 (Tweeter 1", 8 Ohm, 400 Wmax)

 

[ScottG]

Peerless by Tymphany DFM-2535R00-08 1" Compression Horn Driver 2/4-Bolt 8 Ohm

B-52 PHRN-1014 1" Horn 10" x 14" Bolt-On

 

[Defo]

Potential (likely) comb filtering problems with the double Seas and a high enough crossover for the Morel

Yep, unfortunately. But no free lunch in anything. Looking at pretty much all commercial speakers as well as designs by Troels Gravesen, they all seems to just accept the fact that comb filtering is something that you'll have to live with.

Peerless by Tymphany DFM-2535R00-08 1" Compression Horn Driver 2/4-Bolt 8 Ohm

B-52 PHRN-1014 1" Horn 10" x 14" Bolt-On

Is going the small compression driver and horn route feasible in a horizontal design like this? The impedance of a CD in a horn seems to be kind of hard to work with.

 

[Defo]

Here's a crossover simulation of the Seas CA22RNY drivers with the Morel.

Since I don't have data on the Morel, I've simulated it's published response (the one with a 5,6 uf cap) using a Seas 27TBFC/G with a 8,2 uf cap and a modified sensitivity rating.
The end response is pretty darn close to the Morel one.

A nice deep null on with the tweeter non-reverted.

Looks quite good to my eyes?

 

[ScottG]

..roll-off comparison - Morel vs. Seas:

 

[ScottG]

Yep, unfortunately. But no free lunch in anything. Looking at pretty much all commercial speakers as well as designs by Troels Gravesen, they all seems to just accept the fact that comb filtering is something that you'll have to live with.



Is going the small compression driver and horn route feasible in a horizontal design like this? The impedance of a CD in a horn seems to be kind of hard to work with.

-well, you could use a steep (added) low-pass for the .5 driver. That would help considerably - so comb filtering within a reasonably usable (presumably vertical) range could still be decent. (..assuming driver's were placed just about touching each other.) You could also improve upon this with a slight change in vertical orientation between the two drivers - but that might be a bit awkward for this use-case.



DE250's Impedance vs. it on a clone (actually the one below is the original) of the same horn:

https://5e8772ee-a-62cb3a1a-s-sites...m6DyKSuL7hsjMLCU9XxZeMnG-Pc-Y=&attredirects=0

https://5e8772ee-a-62cb3a1a-s-sites..._EuGbooLIZH2-n9DDooaT4wRHdCj4=&attredirects=0

 

[ScottG]

Also you can see its "reaction" to the Eminence APT-150s horn here:

(..blue curve is without horn, black is with horn):

Peerless by Tymphany DFM-2535R00-08 Compression Driver | audioXpress


I'd expect even less of a change in impedance than generated by the APT-150s..

 

[Defo]

..roll-off comparison - Morel vs. Seas:

Seas with a 8,2 uf cap is pretty close to Morel with a 5,6 uf cap. Out of the box they have totally different roll-offs of course.

 

[Defo]

-well, you could use a steep (added) low-pass for the .5 driver. That would help considerably - so comb filtering within a reasonably usable (presumably vertical) range could still be decent. (..assuming driver's were placed just about touching each other.) You could also improve upon this with a slight change in vertical orientation between the two drivers - but that might be a bit awkward for this use-case.

Here's the response of the 0.5 driver and the 1 driver.
Actually didn't think comb filtering between the two would be an issue (too low in frequency), but with just an inductor on the 0.5 driver, it actually still extends quite high. I'll look into a steeper filter on it.

If I were to go the CD/horn route, I was thinking DE250 + Faital LTH102. But since I've tried a CD/horn build some couple of years back, and failed, I'm a bit sceptical I do know a lot more about XO design now tho, so who knows...

 

[Defo]

Got the Morel properly modelled, and turns out it wont work well with the Seas drivers after all

It does however seem to match up pretty good with the Faital Pro 10FE200 with 2nd order filters at 1750 Hz. Might be a bit low of a XO for the Morel tho...