Mods to Improve Andrew Jones Pioneer Speakers?

As many of you are aware, the Andrew Jones designed Pioneer speaker line is considered a giant killer for the price. Mr. Jones is an outstanding designer, very well regarded. However, these were obviously constrained by the very low final selling price.

I'm referring to the models SP-BS41-LR (reviewed by Stereophile with good results), SP-FS51-LR, SP-BS21-LR and the newer versions, SP-BS22-LR and SP-FS52.

Home Theater Speakers | Pioneer Electronics USA

These all have microwave formed curved wall cabinets of decent quality, making them a promising starting point for those who like to mod rather than starting from scratch.

Has anyone had a chance to look into modifying these with better parts/dampening to bring them into a yet higher realm of sonic quality?

The only mod I've seen so far is exchanging the tweeter for a Vifa BC25TG15-04. The fellow that did it (over on the PE forum) was very happy with the results and it looked like a very easy mod. Just swapping the original faceplate onto the Vifa.

Other ideas would be to line the cabinet walls with fiberglass or UltraTouch, or even some Acry-Tech Acoust-X or maybe a homebrew mix of latex based tile adhesive and playground sand (supposedly very good). The trick would be reaching in there! Small woofer hole.

Of course, there's always replacing the crossover components with something more 'audiophile approved.'

As far as appearance, I wonder how hard it would be to add some real wood veneer to the vinyl veneer that's on there.... might test the limits of a good contact adhesive to make that work.....

Any experimenters been playing around with these?

I'm sure Mr. Jones could give us some good pointers in terms of where he cut corners to meet the price point and thus the best places to focus on for improvements.... but he's not talking. :)
 
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At the price point that these speakers sell at all manufacturing goals are to get something that sound good enough for most people and the lowest possible manufacturing cost.

In my opinion it doesn't make sense to spend much time modifying these speakers. Speakers like this are often engineered to get good sound from minimalist materials. Swapping drivers is not likely to yield too much improvement. Although often substituting a 25 dollar tweeter for the 3-5 dollar one in the speaker could easily be a cheap upgrade that would yield instant results.

Would be better to just build a good quality set of speakers. Though better speakers will not often yield an instant improvement because they often need better and more powerful electronics to drive them.

Actually, well designed inexpensive speakers can sound pretty good when driven by high quality electronics.

But, inexpensive speakers are usually designed to sound good with low power integrated amplifiers. They don't need much current to drive them.

If you are using modest electronics to drive the speakers and you want better sound without upgrading all those electronics you need to build at least a medium sized higher sensitivity speaker design. If so, then you need to get all ideas of really small size out of your mind.
 
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A quote from the last link above by A Jones:
"A vertical tube feeding out the bottom sucks away standing waves." this is misquoted. There is a vertical tube inside the speaker. It acts much like a quarter wave stub in antenna design. At the frequency of the main standing wave within the cabinet, it is tuned, by means of its length, internal absorption and location within the cabinet, to short circuit the standing wave and virtually eliminate it. Very neat trick!

I think it actually works, I believe! Nevere heard of this! It should be done more I guess, instead of various felt treatments in BR boxes. Also highly stuffed sealed boxes might benefit from this. Design, material choice and positioning requires lots of testing... I hope someone should have a look inside and tell us about the tube!
 
Have modeled this with LATL. By adding a ¼ wave resonant trap (stub) within the enclosure (if possible). Placement is critical and not easily done maintaining cross sectional area. Adding it externally reduces issues.

Here's an example of a dual trap ¼ wave MLTL...
 

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There is a vertical tube inside the speaker. It acts much like a quarter wave stub in antenna design. At the frequency of the main standing wave within the cabinet, it is tuned, by means of its length, internal absorption and location within the cabinet, to short circuit the standing wave and virtually eliminate it. Very neat trick!
... I hope someone should have a look inside and tell us about the tube!

Most likely it is something like what is shown in the attached Pioneer Patent #US6324292.

Another method(better in my experience) for eliminating standing waves in tall loudspeaker cabinets when you want to minimize use of internal damping material is to use an appropriately tuned perforated panel absorber spaced just above the bottom of the cabinet.

Based on this quote from a review of the YG Acoustics Carmel loudspeaker, it sounds like they are using this method or something similar:
"Interestingly, the main volume of the mid/bass driver enclosure uses no stuffing material at all, and according to YG none is needed. Down near the bottom of the enclosure, however, there is an internally vented, metal-walled chamber loaded with precise quantities of a proprietary damping material. YG’s larger speakers—the Anat and Kipod models—also use conceptually similar dedicated internal damping chambers, albeit ones that are implemented somewhat differently in the bigger speakers."
 

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copy-paste from the document.

When done properly there are several (at least 3) tubes/traps inside the box to kill standing waves. The opening of the tube should be at the node of a wavefront - certaind distance from the boundary.

This one is for the diyer with Aspergers's syndrome!
 

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Trap

If you have a chance look at the now very old TAD 2001H horn. You will see the helmholtz resonator covered with a bit of open cell foam (to keep insects out). The resonator is glassed in atop the main horn body and opens into the main horn structure just behind the mouth.

Cyclotronguy
 
There are 2 threads over at audiocircle.com in the cheap and cheerful circle or area.

I have just completed the totally teardown, new tweeter and mew crossover designed by Dennis Murphy of the SalkSound and Philharmonic fame..,.a real rocket scientist.

The results are absolutely amazing I have reviewed them over at audiocircle.com..

Very well worth the mod,

Alex
 
Folks,

I have a pair of the BS-41s and just noticed a couple of days ago that volume output from one speaker has dramatically fallen. The other speaker has a nice level but the other one is considerably low. I have checked the connections and also interchanged the speakers to rule out a bad connection. Did the voice coil burn or is there an issue with the crossovers. Any thoughts on what could be wrong would be very helpful?
 
Just purchased SP–BS22–LR $66 brand new in the box eBay

$66 brand new in the box eBay
I bought these at this price as test speakers secondary back up because so many reviewer‘s with big names in a lot of followers recommend them at the price point even after a rocky mountain audio fest . All I can say is that they suck I’m glad I did not pay full price for them. If I bought them used for $30 I would not feel so bad but even at $66 brand new out-of-the-box I barely feel they are worth that price point. Test room size 12‘ x 8‘. Speaker placement 2 feet from the back wall 1 foot from the side walls . Source music from Flack files and HD , you Tube‘s highest quality that’s not saying much , Spotify, source amplifiers, #1: marantz 2218 I just recapped the power supply and amp driver board with all high-quality Nitchicon New fets and new transistors. Amp#2: SMSL SA98E. Amp #3: Amp Camp Amp Mono blocks driven by separate left and right linear power supply’s. Speakers used for comparison. 30-year-old surroundsound speakers from my old Harman Kardon AVS10 3 inch drivers. Comparison speaker number two my hand built fostex bk-20 folded horn with Fostex FE206EN drivers. Music genre used classical jazz New Age Indy and Pop. In all comparisons I was very disappointed in these pioneers. Except in one situation at low volumes they were OK near field or my mother who has very sensitive acute hearing in a close confined space in a quiet room then these speakers would be OK . My hearing starts to roll off at 12.7 kHz and I’m stone cold death after 15,000 kHz and I can say the highs on the speakers are muddy dull lackluster . My sons ears on the other hand can hear those mouse illuminators that you plug in the walls outlet to scare away rodents in your house. As soon as my son enters anyone’s house he hast to go around and unplug them out of the outlets because they hurt his ears and disturb him from reading or studying or watching TV. And he says the highs on the speaker sucks in comparison with the other two above mentioned speaker is being used for comparison. On all three amplifiers when you try to turn up the volume the speakers distort badly starting to pop up and click and snap. You definitely cannot enhance the base by turning up the bass or using a based boost feature due to the distortion on the base driver on the pioneers. Hands down compared to the other two speakers there is no comparison. But I am glad I found this thread even though it would be a waste of money to purchase new drivers to stick into these cheap cabinets that need so much mods to make them sound better . As a DAC used for all three amplifiers from the source music A ifI Black Label. Computer for source used Microsoft surface pro 4 and iPhone 6S.
I will put a little time and effort into trying to modify the cabinets and follow other people‘s recommendations without spending money with resources I have I already have a sound deadening material is sound reflecting materials sound absorbing materials and sound deadening adhesives. Let’s see what I can do with other people’s recommendations to make the sound a little bit better.