u/VB_longy

I’ve been working on a large 3D printed waveguide/horn design based on an the ATH R-OSSE formula. It’s a 1” throat waveguide, intended to sit above a 10” woofer in an active DSP speaker build. Measures about 450mm.

I’ve printed and assembled the horn, then bogged and primed it. It’s structurally together, but the finish still isn’t as smooth as I’d like - I can still see/feel some print lines and uneven areas - some of which are my poor filling and sanding.

I’m looking for tips on getting a better final surface. I’ve heard people use spray putty then sand back and repeat. Is that the way to go for a large printed horn, or are there better methods/products? Also curious whether people recommend damping or coating the inside differently from the outside.

For the compression driver, I’m probably going to pair it with either the SB Audience ROSSO-44CD-PK or
Peerless DFM-2544R00-08. The plan is to run it active with DSP, probably crossing somewhere around 1.5 kHz above a 10” woofer. I’ll likely add a series protection cap on the compression driver, and only use an L-pad if hiss/gain becomes an issue.

Any advice on finishing the horn properly, or thoughts on which compression driver would be the better match?

Hi everyone,

First time posting here after lurking for many months. I’m planning my first serious DIY build and would really appreciate feedback before I start buying the remaining parts.

The goal is a pair of active 2-way horn speakers for room-filling playback rather than nearfield monitoring. They’ll be used in an untreated room, around 10 m × 5 m, mostly for house/electronic music.

Current plan
2-way active loudspeaker
External DSP and amplification
No passive crossover, except a protection capacitor on the compression driver
Future subwoofer may be added later

Horn
Custom fibreglass round horn, I have a quote to get a pair fabricated
1” / 25.4 mm throat
420 mm internal mouth diameter
270 mm acoustic depth
Intended for 1” compression driver
Likely crossover target: around 1.2–1.6 kHz depending on driver and measurements

Woofer
Considering SB Audience BIANCO-10MW200
10” paper cone
Intended cabinet volume: roughly 50–60 L
Vented box, likely tuned around 44–48 Hz

Compression driver
Still undecided. Considering:
Celestion CDX1-1747
B&C DE250
LaVoce DF10 or similar

DSP / amplification
Considering miniDSP 2x4 HD or ADAU1701 DSP
Four amplifier channels
Likely TPA3255 Class D amp boards in an external amp/DSP box
One 4-core SpeakON cable to each speaker:
1+/1− = woofer
2+/2− = compression driver
Planning to use a series film capacitor on each compression driver for protection
I’m very open to more simple setups or using a fosi etc but this seems to give good bang-for-buck

Cabinet concept
Approx. 400 mm wide × 360 mm deep × 650 mm high cabinet
On a 250–350 mm stand
18–24 mm ply
Heavy bracing
Front slot port or large round port
Horn in a bold colour

Attached is a draft concept drawing, I’ll be building the cabinets myself. Honestly my biggest fear is spending all the money and time on building the system and ultimately not liking how the finished product sounds. I’m equally considering buying a vintage system and rebuilding it, the issue is there’s not a lot of good options where I live (Northern NSW, Aus) or speakers from Main Audio https://mainaudio.id/ but these are also an unknown, and much less fun than making them myself.

Any feedback, tips or lessons would be greatly appreciated!