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Old 23rd May 2020, 02:49 PM   #11
oldspkrguy is offline oldspkrguy  United States
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Old 23rd May 2020, 02:50 PM   #12
oldspkrguy is offline oldspkrguy  United States
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Old 23rd May 2020, 03:23 PM   #13
oldspkrguy is offline oldspkrguy  United States
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Sorry, not used to new photo software or attaching images here. As you can see; "close shave" (i. e. tight fit)! This is the knock down box from PE (Denovo Audio; PE part no. 300-7076). I knew it was "quite narrow" for the SB29's. I have some 12 X 12 inch MDF panels and 12 X 12 inch high density cork panels. These will mount to the baffle board; MDF on baffle, cork in front of that. This gives the woofer extra distance/space off of the narrow baffle, allows for better mounting and provides a better seal and damping as the woofer frame compresses the cork slightly. Because the internal dimension is very close to the cut out diameter of the woofer; having the woofer "out" an extra 1 inch from the inside will help allow me to get more pad damping material on the walls the full depth of the box. I would normally never have a box width so narrow as compared to the driver size but as I said earlier; I no longer have a shop with lots of tools handy so I go with knock down boxes mostly these days and modify them to suit my needs.

I left one panel off when I glued up the rest of the box. I will make this a removable panel. I will add "cleats" (wood blocks) to the inside edge of all panels so I have a better and stronger fit for the remaining panel to screw into. When I glued this up; I also used fasteners. I used special point (self starting) screws that don't require a pilot hole to be drilled first. I used number 10 screws; I really wanted no. 8 or even no. 6 screws but couldn't find any in stock at the correct length with self start points. I chose flat head, "TORX" drive screws. No. 8 or no. 6 were not in stock with the torx flat head either. At first; screwing these in caused some splitting in the MDF. I increased the drill/driver torque setting, speed up the drill speed and "pushed" in with more force. This gave better results and stopped the splitting. I think this would have been much less of an issue with smaller diameter screws. These splits cause me no concern as there is plenty of adhesive (high quality wood glue) in the joints. I also added more adhesive at the joints as one would normally do with caulk and a caulking gun. So, a very tight and strong bond and seal; I am not worried about anything rattling or shaking loose.

More later...
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Old 25th May 2020, 06:09 PM   #14
oldspkrguy is offline oldspkrguy  United States
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One side almost finished; details and photos to follow. These SB 29's are very well designed and built; if you want some serious kick-*** rock and roll woofers; these are a great choice. For more refined tastes; highest quality HiFi, serious jazz, classical, etc. I think these will NOT be my final choice! I have Satori 6 inch mids and woofers both; also the MA P7PHD, etc. The Satoris and Pluvias just do music MUCH better than the SB29; closed box and vented both.

Inside the box; I have all of the dampening padding installed. I also installed the SS "Flow Resistors" (for Aperiodic). The bass IS much improved in this box vs. the test box. Boominess is gone; a bigger box, damping, Aperiodic ALL contribute to this MUCH better in-room behavior!

What I find lacking is a quick and precise transient response; finer details; nuance; pick your own terms, are just MISSING! I am running them full range now; no X/O, one side only. I think for 40 or 50 Hz up to maybe 150 Hz; these are probably good enough for most people. I really want 40's to low 50's well up to 300 to 400 Hz WITH quick transients; articulation, detail, accuracy, Musicality, etc. I am now leaning toward the Satori 9 1/2 inch or even the ETON 11 inch.

Speaking of ETON 11 inch; I am finding 3 different model numbers online; VERY confusing indeed!

I want the lowest possible fs matched with an appropriate total Q that will agree well with my 33 liter closed (Aperiodic or not) box. As I said earlier; I have a sub-woofer for below 40 Hz; I don't have a large enough room for a vented 9 inch to 11 inch stereo pair (2 ft^3 up to 4 ft^3) will NEVER fit this smaller room unfortunately!
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Old 30th May 2020, 07:05 PM   #15
oldspkrguy is offline oldspkrguy  United States
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Getting back into the project again; had to take a few days off to give the muscles and arthritis a rest! I have pretty much finished up one box; I can still tweak the stuffing, damping, Aperiodic vent, etc. as needed.

For today; I am going to start fine tuning the X/O's (all passive except the sub plate amp). My brother is coming over to give a hand. I played electric bass back in the day along with many of the lower voiced woodwinds. He also; but, he is still an active musician where as I am not. He also learned to play the acoustic (up-right) bass which I never mastered. We also have a cello player and a few piano players in the extended family so now it is time to get the "trained ears" involved.

As I said earlier on; I tried 1st and 2nd order low pass; with and without a Zobel and even played with different Zobel values. Right now; I am trying the 1st order again with the modified Zobel. The idea is to blend seamlessly with the next drivers up the line; the combination Satori mid and Pluvia FR. I don't have a calibrated microphone (coming soon I think!??) but have some very well recorded bass and cello CDs and LPs. I have been using test tones and sweeps available free online; time for more MUSIC!

I have 4 amplifiers total including the sub-woofer plate amp. The sub is totally disconnected and out of the room for now. The "woofer" amplifier is the Dayton I mentioned earlier (APA150). It is bare bones; a power amp with a "volume" control only on front. I have it set for flat, mono (but NOT bridged mono) so I am by-passing the built in sub X/O. This will eventually be set for stereo so these two SB 29's will be a stereo pair (woofers only). I have control over the gain here. The next amplifier is feeding the combination Satori/Pluvia "mids" so I have gain control there also. The super tweeter is now on it's own amp. as well with, yep; gain control.

Well, that was fairly quick! We decided the best blend of bass including harmonics, overtones, etc. is just the 1st order passive low-pass all by itself (NO Zobel, etc.). I am using a 3.6 mH inductor; 13 AWG (Jantzen "P-core"). This is a Ferrous powder type core instead of layered steel or regular Ferrite (they call it "Permite"). Looking at the SB29NRX75-6 impedance curve; I estimate the Z to be approximately 6.7 Ohms at 400 Hz; 6.5 Ohms at 300 Hz. 3.6 mH would then give me a -3 dB point at just under 300 Hz. [Without a Zobel; the HF roll-off will be somewhat less than a true 6 dB per octave (most likely anyway)].

While this may fly in the face of some; I have ALWAYS preferred the sound of a 1st order X/O when I can get away with it. The SB29 drops sharply at about 900 Hz so this is obviously helping me get away with 1st order.

I do eventually plan on getting another calibrated microphone (it's been over 20+ years since I had one). I have the REW software now on my laptop so it's only a matter of time before I can do real, in-room measurements.

I'm happy to say that these SB29's have FINALLY loosened up! Break-in took a lot longer than I anticipated. I think I would probably still prefer the 9 1/2 Satoris or maybe even the ETON 11 inch woofer. At least now I can be satisfied with these SB29's! Originally, they sounded WAY too relaxed without much definition or resolution. The f3 is around 37 Hz; VERY respectable for a closed box of only 1.2 ft^3 (33 l) and that INCLUDES the SS "Flow Resistor" for Aperiodic. As I said before; the calculated Qtc should be almost exactly 0.707 not counting for the stuffing, padding, vent, etc. (Of course; there is also my room gain).

They are starting to open the bars and restaurants on a limited basis as a trial phase in. Many places are reporting more COVID infections after they phased in re-openings so we all must still be careful. BUT; I have a nice place right across the street (literally) with an outside patio. It is Saturday afternoon and there is a cold beer over there with my name on it! ha ha ha ...

Cheers; more later...
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Old 31st May 2020, 10:40 PM   #16
oldspkrguy is offline oldspkrguy  United States
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Currently on the CD player Shostakovich Symphony 1 & 7. This is a DG recording with the Chicago S.O. under direction of L. Bernstein. It won a Grammy in 1991. On Symphony 1; there are some very loud bass drum "thwacks" that really impress (obviously quite a large bass drum)! These SB 29's certainly show their stuff here! I don't have the sub-woofer back online yet but you wouldn't know it here! Yes; there is something to said for more surface area and moving more air in the room. These really should be called 11 inch instead of 10 inch woofers. The basket outer diameter is 290 mm or about 11.4 inches. Seas and SS 10 inch woofers are about 269 to 272 mm for comparison. They do have a larger surface area than the SB29 but has a 3 inch VC and LINEAR X of 22 mm peak to peak! Comparably priced Seas and SS have a linear travel only half to a third of that!

The recording is DG 00289 477 7587

I had the Atlanta S.O. Telarc CD of Stravinsky's Firebird; I remember it also had a huge bass drum. That CD got lost somewhere in my many moves but not since then do I remember a recording with such a loud and low frequency bass drum! One of my old buddies said he read that Telarc had their own giant bass drum and it was used on many classical recordings regardless of which orchestra, conductor or city.

I do like the larger pipe organs so I will still need my subs for the 16 Hz to 32 Hz octave!
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Old 1st June 2020, 10:55 PM   #17
oldspkrguy is offline oldspkrguy  United States
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Currently on the CD player we have bass player Eddie Gomez. "Power Play" and "Street Smart" both. Back in my US Navy days; I traveled the world (literally). My favorite place on Earth is the district in Tokyo known as Akihabara. This translates loosely to "electric town". It is the big boy toy electronics and stereo capital of the world! Me and a few of my buds had the weekend off so there we went. We took several CDs and hit all of the "high end listening salons". This was in the 90's but even then we heard stereo systems costing in excess of $500,000 US. To this day; I still have an aural memory of that experience!

Then; we went back to Yokosuka to the exchange and did even more listening...Klipschorns, B&W, Infiniti, etc...the best available on base; top of line that most Sailors and Officers could afford anyway.

What I now have meets or exceeds these experiences in almost every way and well within a reasonable price range!

More later; critical listening and evaluation moment of "ZEN" going on now!

(ps; I forgot to add; on the streets of Tokyo; you can buy beer out of a vending machine and walk around drinking it so that was real bonus for ANY Sailor for sure!)
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Old 2nd June 2020, 07:49 PM   #18
oldspkrguy is offline oldspkrguy  United States
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Gary Karr: J.S. Bach Solo Suites- Complete

On the CD player now. JS Bach Suites for Cello as played on double bass. Excellent recording!


Brian Bromberg - Brian Bromberg

On the wish list; I had the original CD; also lost in the shuffle. This is a remaster. His "My Bass" is a great electric bass demo track; check it out on YouTube

My moments of "ZEN" bass and cello critical listening days continue...
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Old 2nd June 2020, 10:58 PM   #19
diyiggy is offline diyiggy
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sure, the cello suits played by Rostro. is one of my disc for critical listening and loudspeaker or devices benchmark, as the jazz Bass... piano (one I like is the 15 first minutes for the test of K Jarreith La Scala. And voices of course. Indian tablas for the rythm and speed consistency... Triangle and drums ... We are difficult!



Like the description and story and follow the thread, thanks for all the details
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Old 3rd June 2020, 12:41 PM   #20
oldspkrguy is offline oldspkrguy  United States
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Originally Posted by diyiggy View Post
sure, the cello suits played by Rostro. is one of my disc for critical listening and loudspeaker or devices benchmark, as the jazz Bass... piano (one I like is the 15 first minutes for the test of K Jarreith La Scala. And voices of course. Indian tablas for the rythm and speed consistency... Triangle and drums ... We are difficult!



Like the description and story and follow the thread, thanks for all the details
Thanks!
I always said if you got the piano and female singing voice just right; you've really done something! Now, about the upper overtones and harmonics of the violin; THAT gets really tricky!

What are some of your other favorite music testing tracks? I have a CD player and a turntable; both very good sounding for their given price range. Like everything else; I'm always wanting to improve things!

Cheers!
 

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