B652 upgrade and other parts

[jpphun]

Hi all, looking to set up a cheap desktop system at work.
i found this in the reviews but am not that experienced in modifications. Can anyone help.
my goal is to match the B652 with a lepai lp-2020a and a dac(not sure yet, probably schitt but would take advice)

post was from Joel Grant. [COLOR=#38393B !important]From the factory, these only have a cap on the tweeter and no actual crossover network. The mini-AMT tweeters these come with are identical to those that cost $60 a pair and the woofers (though very cheap) are very good at reproducing a wider frequency range than most mid-bases here at PE. Thus, the drivers are good and the enclosures are okay if you make a couple simple modifications. What I did:
1) bi-wired the drivers
i am not sure what this means, did he change the binding posts (and wires) to just allow them to be biwired?
2) added cross bracing to the enclosures (little oak beams)
i get this , makes sense, more rigid
3) added 5 ounces acoustastuff to enclosures
i got this, makes sense
4) customized PE 4.5khz crossovers for the networks created by 4 drivers (woofers in series, tweeters in parallel).
IS this is this part number? Dayton Audio XO2W-4.5K 2-Way Speaker Crossover 4,500 Hz
Tweeters have been padded 3db
What does this mean? did this occur from the crossover or was something purchased and added here, if so what was it?
and a zobel has been added to the woofer circuit to keep the crossover stable.
so my research shows a zobel is a resistor, which resistor was purchased and where was it added?
Thank you for any help.


this is the remainder of the review.
The result is really impressive sound. Eliminated the cone breakup over 4khz present in these woofers that keeps the B652-AIR from sounding great from the factory. Much better bass response than I anticipated. Love the non-directionality (off-axis) response of the AMT. I purchased both b652 sets for half price as open box making the total mini-project under $150 for great sound. If PE would include a filter on the woofer at 4-4.5Khz to tame the sharp cone breakup peak I would give these 5 stars. This could be implemented for a couple dollars.[/COLOR]

[Millstonemike]

If you haven't bought the Lepai yet, I'd go with the new Lepai 2020TI version and pair it with a 24v supply (or 19v laptop brick). I think you'll need the extra power for B652s.

Can you post a link to the Joe Grant mods? I couldn't find it.

[bullittstang]

I would be skeptical of his modifications of the XO. Not enough information given to know exactly what he did, but bi-wiring and running the woofers in Series and tweeters in Parallel is not going to give you "stereo" sound.
Best modification is always to stiffen up the cabinet - 1/2"-3/4" wooden dowels are a great option and easy to fit. One top to bottom and one front to back should be sufficient.
A rework of the XO could certainly give better results, but you would need someone that has actually taken some measurements of the woofer and tweeter so you or someone could SIM an updated XO.
I have heard they sound pretty good as is, have you already bought them and listened to them? Most on this forum are "all-in" on the DIY side, so we modify everything, but PE products have some real R&D behind them and typically fit the average persons needs very well. Just my thoughts.

[Millstonemike]

Here's a B652 mod with a little more "science" behind it. Since you have the "Air" version, I don;t think the tweeter XO mods apply,b ut the woofer mods may. Replacing the tweeters NPE cap with a film cap can't hurt.

http://zaphaudio.com/Dayton-B652.html

[carlspeak]

Not sure if the OP has the original B652's or the AMT version, the 'AIR'. I modded the AIR version with much success. Details and MEASUREMENTS can be found here....

http://techtalk.parts-express.com/forum/tech-talk-forum/63991-dayton-b652-air-improved?244602-Dayton-B652-AIR-IMPROVED=&highlight=b652

[augerpro]

I reworked the crossover here: http://techtalk.parts-express.com/fo...ayton-b652-air . Cost for the mod is about $14 per speaker. I tried to keep it cheap so the primary focus was on the woofer breakup, tweeter roll-off, and BSC.

[jpphun]

Thanks for all the help.
I have not heard them yet, soon though. The post from Joel Grant was int he reviews of the post. Looks like i have some options so a nice little project.

[jpphun]

So, have the speakers, put in the PE XO 4500, some cross bracing, polyfill, and sealed up everything. After a couple of days listening to them they are filling out quite nicely. no my question is, should i use these to replace my HT set up. The current HT set up is a very old ML sub and on the wall microspeakers. The sub actually died (had a hum). So i am wondering if these would be a good replacement and is the XO 4500 the right one (this was from a comment in the reviews for these speakers) Thanks for all the help. Should i just follow the 14$ XO mod from above? The PE XO is 25$ but i wonder if the overall bit is better.

[wogg]

So, have the speakers, put in the PE XO 4500, some cross bracing, polyfill, and sealed up everything. After a couple of days listening to them they are filling out quite nicely. no my question is, should i use these to replace my HT set up. The current HT set up is a very old ML sub and on the wall microspeakers. The sub actually died (had a hum). So i am wondering if these would be a good replacement and is the XO 4500 the right one (this was from a comment in the reviews for these speakers) Thanks for all the help. Should i just follow the 14$ XO mod from above? The PE XO is 25$ but i wonder if the overall bit is better.

2 answers...
Yes, the crossover mods above that include actual measurement data to develop the crossover will be better than the off the shelf Dayton crossover.

Yes, the B652's will be better then on the wall micro-speakers for your HT.

[Whitneyville1]

Any half-way decent sub-woofer will fill-in the bottom octave either of the versions of the B652's can't reach. The general consensus that the woofer portion of the XO on either B652 is accurate. The single cap crosses over at almost the worst portion of the mid-woofer's break-up freq. Zaph's site and XO mods make this very clear. IMO, the $15 XO will sound better than any off-the-shelf XO.

[carlspeak]

Here's a B652 mod with a little more "science" behind it. Since you have the "Air" version, I don;t think the tweeter XO mods apply,b ut the woofer mods may. Replacing the tweeters NPE cap with a film cap can't hurt.

http://zaphaudio.com/Dayton-B652.html

There was a period where defective tweeters were shipped in the soft dome version like the one Zaph upgraded. It wasn't too long after that, the 'AIR' version appeared.
wonder if he had one of the soft dome versions with a bad tweeter..

[jpphun]

Thanks for the feedback. Going with the Auguerpro mod. I do have one question, I am getting around the parts list, but i am unable to find the 260mohm resistor labeled as R5 in the PE catalog. Any help with this?
Then i am ready to place the order.

[Millstonemike]

Thanks for the feedback. Going with the Auguerpro mod. I do have one question, I am getting around the parts list, but i am unable to find the 260mohm resistor labeled as R5 in the PE catalog. Any help with this?
Then i am ready to place the order.

It's not their best "audio grade" part but I would think the 0.27 ohm resistor PE stocks will work fine. Others may confirm or refute ...

[Chris Roemer]

That "R5" is just the DCR of the coil (around 0.3 ohms - just use the new Dayton #18 0.33mH air-core).

[Millstonemike]

That "R5" is just the DCR of the coil (around 0.3 ohms - just use the new Dayton #18 0.33mH air-core).

Didn't think of that. Thanks for the correcting.