How to make a good three way loudspeaker - which bargain drive units ?

[Severian]

You have described me to a T there lol. Toss in the fact that I live next to a highway and things get tricky.

Yeah, and of course once I got everything set up, my neighbor fired up a lawn mower.

 

[DanielT]

Tangband. How are your thoughts regarding mounting tweeters with or without waveguide? If I remember correctly, have you built a pair of speakers with WG before? Why not try without WG this time?

If you use the SB Acoustics SB15NBAC30-4 and set the crossover to 2.2kHz, as you said you were going to do, then no WG is really needed, right? That regarding matching of the drivers you intended to use. See attached picture off axis response for SB15NBAC30-4 and thus the possibilities for matching with tweeter SB acoustics adc 26 without WG.

SB Acoustics SB15NBAC30-4 | HiFiCompass

The THD measurements at distance of 20 mm and voltage levels from 4 to 5.6 Volt were carried out with High Pass Filter "on" (4th order Butterworth type, 20 Hz cutoff, HPF4-20). The THD measurements at distance of 315 mm and voltage levels from 2 to 4 Volt were carried out with High Pass Filter...

hificompass.com

Here for inspiration. The round shape. Seems to measure well for Joseph Crowe when he tests it. Okay, with such a construction, it is the opposite of directing the sound via a WG, but it has its pros and cons. Or rather the sound it creates in the listening room vs WG mounted tweeter maybe you like it more then....or less, what do I know.

 

[DanielT]

A little more inspiration. Here a nice build with a FaitalPro 6HX150 coax at the top and an 8 inch bass at the bottom.

Tangband, you like coax if I'm not mistaken? Maybe something like that that you can try? Attached images, FR and distortion at 85 and 95 dB.

Coaxial Speaker Build Thread with FaitalPro 6HX150

Ok time for a new build thread! I’ve been planning my InDIYana event “Keeping up with the Jonzes” build for some time and am finally getting splinters from it! So let’s start with the name, it’s a “coaxial” driver build, or coax, to coax is to be persuasive, these cabinets will be very...

www.diyaudio.com

Damn nice and good woodwork on those speakers I must say.

Damn nice and good woodwork on those speakers I must say.

Edit:
The FaitalPRO 6HX150 costs $286. I don't know if it's a bargin or not, but I thought the DIY speaker above with that coax was really nice and it also seems to sound good.

"Choose the coaxial 6" 6HX150 driver from FaitalPRO for point-source, full range applications where space is limited. High output and power handling are combined with low distortion due to the use of an aluminum demodulation ring in the woofer's motor."

Home

FaitalPRO 6HX150 6" Neodymium Coaxial Driver 8 OhmFaitalPRO's 6HX150 professional 6" coaxial driver features neodymium motors for both the 6" woofer and the attached compression driver, for a full-range, point-source solution that weighs just under 3 pounds. A cast aluminum basket handles the...

www.parts-express.com

You don't need many watts to drive the HF part in the coax because it has a sensitivity (1W/1m) of 104 dB.

 

[Andrej]

I'm probably too late to be useful, but it might be worth it in the future. I used inexpensive drivers in waveguides/horms for the tweeter and the mid. I used Daytom AMT Pro and the above-mentioned SB acoustics 6in ceramic driver, and 15in FaitalPro I got used. Total driver cost/speaker is about $600. Extremely low distortion, which I measured, per driver (using Hypex 3-way plate amp, with DSP - note a notch at 40Hz to tame the dominant room resonance). I first set the output to be about 100 dB at 2 meters in midrange (simulating 106dB/1m), showing distortion at that location, then I moved the microphone to 4in from the bass driver cap, or 4in from the mouth of mid and tweeter horns. Distortion drops when measuring at 4in, removing many of the room effects, while also smoothing frequency response. It is informative to notice how the frequency response gets progressively smoother going from low to high frequencies (when compared to the 4in measurements). Waterfalls show absence of resonances, except at lowest frequencies when even at 4in you get room modes.
This is intended to be a center channel speaker in a dedicated media room, so deep bass was not a concern, but high output at low distortion, and good directionality down to low-ish frequencies was, thus the waveguides. The main speakers have much larger waveguides, going down to about 160Hz.
Final photos are of the speaker during buiding, and with the tweeter and the bass sections completed.