[DMurphy]

Dennis,

Since many of us already have the speakers and it is not cost effective to ship the speakers to you for the complete mod, do you have a curve for just the tweeter change out?

2nd question: It may be of interest for us to ship just the crossover for the mod and each individual could then order and install the new tweeter? Would this be of interest? With flat rate shipping boxes, this may be cost effective depending on the cost of the crossover mod.

Thanks

Hi.   You wouldn't want to just swap in the new tweet--that would produce a large dip in the lower treble response.   You would need to add a 4.0 uf series cap before the positive tweeter terminal.  That's an interesting idea about sending me the stock crossover.  You wouldn't want to order the tweet yourself--I can get it way cheaper.  I'll have to total up the cost, but it's not going to be super attractive.  I can sell a new pair with the mod for $150 only because I get the speaker wholesale and I don't incur any shipping costs.  You can't infer from the $150 cost that the mod only costs about $25 (based on the current retail price of around $129).   I would have to charge more like $75 plus return shipping to make it worth doing.   And even then I would be paying myself about $3 an hour.   The most attractive option for current owners, IMHO, would be to just do the tweeter and cap mod.  I've attached a simulation of that version.   The rise at the top end  looks worse than it sounds.  I doubt that you could hear it at all. 

[DMurphy]

I guess I'm confused. Are you fixing a specification error that Andrew over-looked or are you fixing a manufacturing tolerance defect? I certainly can't believe that Andrew would let a dip like this be the norm for standard product. And if you fixing this for a manufacturing tolerance, then none of the "repairs" will count, as one must assume that the deviation of the tweeter has a typical +/- tolerance to it's performance.

So, unless you sampled many units to determine that there is in fact a design error, or a manufacturing error, then the fix has no frame of reference, as it seems the tweeter's performance can be "all over the place".

So then I must ask, what are you actually trying to accomplish here?

Wayner

Hmmmmm     We seem to be talking past one another.   I'm saying that the actual run of stock tweeters varies widely in frequency response, but that they all have the same sonic problem that caused me to do the mod.  I don't know what the response profile was for the tweeter(s) Andrew used to develop the crossover, but I suspect it was like the "good" unit I posted.  The xover is extremely well done--lots of bang for the buck with excellent phase integration.   But I don't like the inherent  sound of the tweeter.   So I replaced it and adjusted the Xover for it keeping as many of the stock parts as I could.  And I like the new speaker much better than any of the stock units I've heard.  That's it.  there ain't no more. 

[Wayner]

Well, the up and down hum that is shown on the graph is what I believe the first model XX-XX21-XX had, and as I read his story, he changed the throating on the tweeter to smooth this out and to increase the speaker's efficiency for the now current SP-BS22-LR.

With the new mod, has the speaker's efficiency changed, and has the off-axis response changed?

Wayner

[DMurphy]

Well, the up and down hum that is shown on the graph is what I believe the first model XX-XX21-XX had, and as I read his story, he changed the throating on the tweeter to smooth this out and to increase the speaker's efficiency for the now current SP-BS22-LR.

With the new mod, has the speaker's efficiency changed, and has the off-axis response changed?

Wayner

I don't know the history of the tweeter.  I'm not sure why he would want to increase the sensitivity--he has to pad it down with a 6.8 ohm series resistor and a 33 ohm parallel.  For what it's worth, the 22's measured with more harmonic distortion at the low end than other tweeters I've worked with.   But distortion measurements are tricky to do, and I wouldn't want to swear that what I'm hearing is harmonic distortion.  It's just a possiblity.  Do you happen to know whether the tweeter uses cooling fluid?  I haven't disassembled one yet to see.  inconsistent application of fluid could cause QC problems like this. 

For the full mod, sensitivity is down maybe .5 dB.   I'm using more inductance on the woofer to blend better with the Vifa.   Off axis response is typical for this kind of design.   There's a little flare at the crossover point due to the tweeter's superior dispersion, but not any more (and perhaps a little less) than the vast majority of speakers.  It's a little hard for me to get a handle on the off axis behavior of the stock tweeter since the frequency response varied so much. 

[dlparker]

.....
   I would have to charge more like $75 plus return shipping to make it worth doing.   And even then I would be paying myself about $3 an hour.   The most attractive option for current owners, IMHO, would be to just do the tweeter and cap mod.
....

$75 plus shipping to send a pair to you have you do the mods? Sounds like a deal to me! Put me down for one! Where and when do I ship?

[DMurphy]

$75 plus shipping to send a pair to you have you do the mods? Sounds like a deal to me! Put me down for one! Where and when do I ship?

Hi.  Seems kind of expensive to me, but I guess they might be worth a total cost of around $200.  I plan on offering the modded speaker as a Philharmonic Audio offering (with full disclosure on its origins), but I will feel more comfortable about doing that after I get another review or two.  If I don't go through with that, then I couldn't make any bulk orders and couldn't meet the $75 price.   We'll have to see in a week or so.   

[MLS]

Did I miss which tweeter (Vifa) was used in the upgrade? Is it only the addition of a 4uf cap before the tweeter terminal?  I think I read something about more inductance on the woofer also?

 I looked but could not find anything. 

Sounds like a very doable DIY project for someone who has a soldering iron. 

Thanks,

Scott

[DMurphy]

Did I miss which tweeter (Vifa) was used in the upgrade? Is it only the addition of a 4uf cap before the tweeter terminal?  I think I read something about more inductance on the woofer also?

 I looked but could not find anything. 

Sounds like a very doable DIY project for someone who has a soldering iron. 

Thanks,

Scott

Hi    This is the tweeter, which can now be ordered retail for close to my wholesale price.    http://www.parts-express.com/vifa-bc25tg15-04-1-silk-dome-tweeter--264-1040

There are two mods--one just replaces the stock tweet with this Vifa, and adds a 4.0 uf capacitor in line with the tweeter positive terminal.  It also requires you to clip the 33 ohm resistor on the stock board, which can be done with a nail clipper.   The other more involved mod requires a complete rebuild of the Xover board, including more inductance on the woofer and some added and replacement parts to the stock tweeter circuit.  That's the mod I intend to offer as a finished speaker for $150/pr. 

[dlparker]

Hi    This is the tweeter, which can now be ordered retail for close to my wholesale price.    http://www.parts-express.com/vifa-bc25tg15-04-1-silk-dome-tweeter--264-1040

There are two mods--one just replaces the stock tweet with this Vifa, and adds a 4.0 uf capacitor in line with the tweeter positive terminal.  It also requires you to clip the 33 ohm resistor on the stock board, which can be done with a nail clipper.   The other more involved mod requires a complete rebuild of the Xover board, including more inductance on the woofer and some added and replacement parts to the stock tweeter circuit.  That's the mod I intend to offer as a finished speaker for $150/pr.

I may very well wind up with two pair of these - my existing pair that I mod myself, and the one I buy from Philharmonic Audio!

[jmc207]

Dennis,

Is the tweeter the BC25 or the DX25? I believe you mentioned the DX25 on a different site. Or, have you changed to a different Vifa tweeter?

Either way, hope this works out as I would like to get a modified pair.

Thanks, John

[DMurphy]

Dennis,

Is the tweeter the BC25 or the DX25? I believe you mentioned the DX25 on a different site. Or, have you changed to a different Vifa tweeter?

Either way, hope this works out as I would like to get a modified pair.

Thanks, John

I've used both models, but this one is the BC25. 

[MLS]

Thanks Dennis

I appreciate the info and your hard work.

Scott

[jmc207]

Thanks Dennis

I appreciate the info and your hard work.

Scott

Agreed!!!

[ttan98]

Dennis,

Will you publish the x-over schematics here or do we write to you individually?

Thanks.

[Wayner]

Here is a freq. resp. graph published in the Absolute Sound:


Wayner

[alphaiii]

I've used both models, but this one is the BC25.

Is there an appreciable difference between the two, other than retail price?  Do both work well with either of the mods?

[DMurphy]

Here is a freq. resp. graph published in the Absolute Sound:


Wayner

I wish the Absolute Sound would publish frequency response plots.   This one is from Stereophile, and shows considerable smoothing, plus it's averaged across a 30 degree listening window.  Still, it's pretty consistent with the "good" plot I showed.   Again, it's not the FR that prompted me to do the mod. 

[DMurphy]

Is there an appreciable difference between the two, other than retail price?  Do both work well with either of the mods?

They differ in their low-end characteristics, although I haven't tried the DX25 with this speaker and can't say for sure how it would work.  I did use it with the BS52, and ended up with some brightness at the low end, an indicatiion that it was being worked too hard.  It would require extra components to fix that, and I didn't need them on the Vifa I'm using for the 22.

[alphaiii]

They differ in their low-end characteristics, although I haven't tried the DX25 with this speaker and can't say for sure how it would work.  I did use it with the BS52, and ended up with some brightness at the low end, an indicatiion that it was being worked too hard.  It would require extra components to fix that, and I didn't need them on the Vifa I'm using for the 22.

OK, so the BS22 mod uses the Vifa BC25... and not the DX25.  As mentioned by jmc207, you linked the DX25 over at AVS. 

[Donald]

Thanks Dennis

I appreciate the info and your hard work.

Scott

Agree with MLS. Thank you for all of your time and effort.