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Insomnia has its advantages...
So earlier this week I noticed PE released a mid that is essentially a re-badged version of the Goldwood "heavy duty" 8 ohm midrange.
I noticed it has a pretty linear response, and as luck would have it the little Peerless waveguide tweeter is on sale. I added a pair of the 8" GRS subs and have the components for what might be a pretty nice little 3-way.
Years and years ago I built an all GRS TM/W as a rehearsal monitor for the band and I've been itching to do another ever since. The first version used the 8" poly, the sealed back mid, and that little Audax clone tweeter. It was ok. Worked perfect for playback when I would record or when surfing Youtube for new songs to cover.
So since I have insomnia, I drew this up (I didn't do the roundovers on the Isometric portion because quite frankly it ain't quick or easy and I'm damned tired right now):
Did a quick model with 0.5 ohms added series resistance and changed Qa to 20 to reflect some stuffing which it will need.
Q is a little high at 1.2, but screw it - I've heard higher Q speakers sound, well - fun. These should have a kick in the pants with that ~80hz ripple.
Don't know when I will start, but it won't be this weekend. Gotta finish up that damn truck. If my parts get here. Which they have not yet. Oh well. Sawdust it is. Gotta machine baffles for my 4" roundup, gotta knock together cabinets for the 4" SB/GRS ribbon project, and now these. Gonna be a messy garage for a few days.
I'm going to try and grab another couple hours of sleep.
Comments
link to the mid driver ? Thx
https://www.parts-express.com/GRS-5-1-4-Sealed-Back-Midrange-with-1-Voice-Coil-8-Ohm-292-433
I designed a system for a friend that has a sealed 10" woofer with a Qtc around 1.4 and an Fsc of 72 Hz. (3.5 db peak at 82 Hz) and they have great sounding bass, very full and rich. I think your design will be just fine.
Cool project with only about $100 in drivers👍
I'm going with a vertical alignment.
Old school with tweeter and mnidrange offset. It goes against my belief system but one must not get too comfortable within said belief system, so there.
Also will expedite crossover design on primary axis. I suspect the midrange will need all the help it can get. Tweeter will be as easy as pie due to the wageguide loading, and the offset baffle location. Woofer should be easy as well due to it being a poly cone. Have to ZOBEL...BEL...BEL...bel...bel.. the damn thing I am sure.
Cabinets cut and glued up today. Big day of routing tomorrow. Four pairs worth. Yay.
Ok, no routering today. Finishing up gas tank swap/interior upgrade on truck. Tomorrow is a new day...
I put in those new fangled 3-point safety restraints. That was a dumb job. Wow, what a pain in the peepee hole.
You probably should have cut the woofer holes BEFORE mounting in the truck.😉
Between tank and passenger side cab corner there appears to be room for a 6.5" tube style subwoofer. I imagine one of the Tang Band 6.5" drivers would be superb with one of those fancy new Class D amps.
Someone's been a busy beaver!
Better ramp it up, Craig, or you're going to lose this year. Jr's got you got a good head start on you!
InDIYana Event Website
He's already at the 660' mark and I'm still sitting on the starting line...
You got tree-d Craig!
The mid is garbage, so I'm going to drop the $7 mid in there instead. I have used a coupla three times before and it always impresses me.
The tweeter also will not work in a 3-way, it is fine otherwise. The combination of the waveguide, highish FS, and high impedance peak all conspire against a higher crossover point. I'll save it for a rainy day. I bought the Dayton DS soft dome instead. Liked what I heard in Wolf's design at Indy, so... yeah.
Onward and upward as it were.
Yeah, the DSN25F4 seems to be a great tweeter. I've used it twice now. I crossed it at 3rd/5k and -13dB pad. Loafing for sure it is.
InDIYana Event Website
I used it at 3k in the OSFA bluetooth speaker, so it can be used lower.
InDIYana Event Website
None of this helped the mid:
So, the https://www.parts-express.com/GRS-5-1-4-Sealed-Back-Midrange-with-1-Voice-Coil-8-Ohm-292-433 is a complete POS even without all of the snail trails you allowed to gather upon them?
Yeah, the $7 GRS sealed back mid is light years better.
Looking forward to the part number of the GRS and your findings, Sir.
https://www.parts-express.com/GRS-5SBM-8-5-Sealed-Back-Midrange-292-432
I've used it several times, I'm a fan.
Some modeling has yielded this with 11 (inexpensive) components:
Listening dependent of course, I usually take about four hours if persistent measuring, listening, and tweaking (no, not like that - my drugs of choice are all legal dammit) after using software.
Old school crossover points of ~1000/5000. Remember, this design is all about affordability and pushing crossover points higher allow me to do a couple of things.
The natural roll-off on the top end of the midrange is managed very well by a single coil. Similarly, a small cap is all that is needed on the bottom end. An L-Pad finishes off the midrange. Very cheap to hammer the mid into shape.
The woofer has a very nice response to work with. A damped second order using a small coil (small for woofer in a 3-way) and a large cap (less than $3 at PE) with a resistor to tailor the roll off.
The tweeter is somewhat problematic on the bottom end due to excessive high Q resonance. Driving the XO point to 5k gets that resonance -30db from the fundamental so I did not worry about tanking it. Otherwise, typical 3rd order electrical using pretty small values.
Anyways, this is the path I have chosen for this little monkey coffin.
That went very well, damn. I'm calling it. Will post some data later. Did not take polars of finished product since I pretty much know how offset HF drivers behave with the topology I chose.
The GRS subwoofer is just great. These should be fun speakers with enough power behind them. The HF and MR are crossed high enough they should be able to take some stress, and the woofer has plenty of thermal and mechanical grunt to play fairly loud.
Pissed the wife off this morning lol, she works from home M and F every week. I am on staycation currently. The 95db whoop whoops disturbed her.
So yeah, get your ducks in a row measuring and have a demo or two handy when it comes times to listen and tweak.
Long live the monkey coffins.
I'm working on a writeup currently. I'll post it here.
Writeup will seem a little condescending to anyone who has built speakers for 30 years, but I doubt anyone who has built speakers for 30 years will build these. Targeted to the novice/newbie.
I think I am out all of $200 on these, and come Iowa I think some of you may be impressed with them.
Time for beer.
You gotta love a good monkey coffin!
If I had the physical space, I would build a dual 15" 4-way using all pro drivers and power them with a kilowatt.
My neighbors need to know my love of musicians like Passenger and the Boss.