MBOWI 3-Way Phase and Measurement Question

[Alex2507]

The GTG was attended by a handful of guys that I've had the pleasure of meeting on a couple of previous occasions. I showed them the differing as-built high pass xo schematics that I had done the repair work on and thanks to Everett, I had the original DM schematic for them to look at. The phase of the drivers got played with and we tried inverting the bass cabinet to provide a little boundary gain for the 10" Peerless driver. I mean we tried everything and having the GR Research mid in phase with the woofer and tweeter was the crowd pleaser. I needed a lesson in what to listen for in regards to the changes in sound due to differing phase alignments.

I really need to look at the band pass and low pass xo boards to verify design adherence. As Swerd pointed out, this is a great way to learn stuff about xo's. DM provided a couple of options to balance the top end for in-room preference and that showed me what parts to tinker with. I thought they were a little bright at the GTG but once I have them back in Mantown, I'll get REW fingered out again for main listening position measurements.

The speakers are on their way to Eddy's for paint or Formica or something on the tortured bass cabinets. I'm considering making the xo boards fit for public viewing and keeping them external for a while: at least until I am satisfied that nothing wonky happened to them along the way. Plus I want to be able to swap out parts and pieces in the xo's. Verdinut was good enough provide some terminal strips to aid in this circuit board business. And I've got some plexiglass to help safeguard the boards while still providing a view.

EVERYBODY agreed with Rick that the high pass boards should be identical. Imagine that. Even so, the speakers did well in lots of areas, like really well. Making the boards symmetrical has the potential of further sweetening the performance of the OW1 tweeter. Parts Express, ready or not ... take my money!!!

I'll hammer out the remainder of the details to bring them up to their full potential. These speakers are another case of the upgrade being way more expensive than I'm interested in paying. This shouldn't take too long either. I miss having them and the weather is closing in.

So ... chop chop.

... and this xo thing has me really wondering about all the stupid stuff I could be doing with the parts and pieces of various Primus speakers. If I draw the schematics, I should be able to learn what Infinity did differently for identical drivers in a 2-way and 3-way design. Then maybe play with that stuff for ... fun?

I can't wait for the next "nerdy sausage-fest" ~billshu

 

[Swerd]

Thanks for writing all that. I haven't been to a DIY meet in over 10 years. Dennis is too busy and doesn't organize them anymore.

The closest I can manage is the Capital Audiofest coming up soon. Dennis & Jim Salk say they'll be there. The audio shows I've seen in the past are always interesting at first; seeing so many overpriced and sometimes terrible sounding speakers can be fun. But before long too many salesmen talk too much about their amplifiers, speaker cables, or turntables, and I have to walk out. That's when signal-to-noise ratio of audio shows goes quickly downhill. DIY speaker building meets are more fun.

 

[Alex2507]

I know to get 10 watt resistors but wondered about the voltage rating on the caps. PE has 1% tolerance on 250 volt caps of CLOSE (6.8 for 7 and 8.2 for 8) value but Solen has those values at 5% and a 400 volt rating. The value I need is 7 and 8. Prices are close enough to the five dollar mark that I don't care about cost. Not sure which to get.

I'm not going to bother trying to match anything on my boards. Just need a nod toward either the 250v or 400v rating.

tia

Edit: I just read that 100v rating is good to about 200 watts. Those are under a buck ...

 

[Swerd]

I know to get 10 watt resistors but wondered about the voltage rating on the caps. PE has 1% tolerance on 250 volt caps of CLOSE (6.8 for 7 and 8.2 for 8) value but Solen has those values at 5% and a 400 volt rating. The value I need is 7 and 8. Prices are close enough to the five dollar mark that I don't care about cost. Not sure which to get.

PE 1% tolerance vs. PE 5% tolerance
I have an inexpensive hand-held LC meter that I use to check caps and coils. With that meter, I've found that all of PE's 5% caps measure exactly as printed on the cap. If the label said 6.8 µF, that's what I measured. The one time I bought some 1% caps, they were no better. Those 5% caps have yellow ends, and the 1% caps have silver ends. Both are the same length and diameter. I think they're made in the same production run at the same factory. The only difference is that the silver ended caps are checked for 1% tolerance. and the yellow caps are checked for 5%.

Voltage ratings 250 volts vs. 400 volts
It has often been said by others that the Bennic company in Taiwan makes PE's house brand caps. Madisound sells Bennic caps and their Bennic XPP line is said to be the same as PE's 5% caps. Those caps have printed labels that say "160 volts AC, 250 volts DC". (Remember that audio is AC.) See the photos of each cap. So the same is probably true for PE's caps. For what it's worth, the MB27s are built with PE 5% caps or the Bennic equivalent.

If I can't find the right size from PE or Bennic, I'll order a Solen or an Audyn Q4 (both are rated at 400 volts).
6.8 µF cap prices:
PE 1% $5.19
Solen $4.10
Audyn Q4 $3.74
Bennic 5% $3.05
PE 5% $2.75

For what it's worth, Dennis like using the Audyn Q4 caps because their leads are a bit longer and thicker. That makes assembly easier.

I'm not going to bother trying to match anything on my boards. Just need a nod toward either the 250v or 400v rating.

Remember that the caps with higher voltage ratings are larger in physical size. That may matter as you assemble a board with little space on it.

I just read that 100v rating is good to about 200 watts. Those are under a buck ...

If that 100v cap is metalized polypropylene or mylar, its OK. Stay away from Non-polar electrolytic (NPE) caps. If I remember, they are usually rated at 100v and are cheap. Their capacitance ratings often vary by more than 10%. How many do you have to buy to get two that are both in spec? They just aren't worth it.

 

[Alex2507]

PE 1% tolerance vs. PE 5% tolerance
I have an inexpensive hand-held LC meter that I use to check caps and coils. With that meter, I've found that all of PE's 5% caps measure exactly as printed on the cap. If the label said 6.8 µF, that's what I measured. The one time I bought some 1% caps, they were no better. Those 5% caps have yellow ends, and the 1% caps have silver ends. Both are the same length and diameter. I think they're made in the same production run at the same factory. The only difference is that the silver ended caps are checked for 1% tolerance. and the yellow caps are checked for 5%.

Voltage ratings 250 volts vs. 400 volts
It has often been said by others that the Bennic company in Taiwan makes PE's house brand caps. Madisound sells Bennic caps and their Bennic XPP line is said to be the same as PE's 5% caps. Those caps have printed labels that say "160 volts AC, 250 volts DC". (Remember that audio is AC.) See the photos of each cap. So the same is probably true for PE's caps. For what it's worth, the MB27s are built with PE 5% caps or the Bennic equivalent.

If I can't find the right size from PE or Bennic, I'll order a Solen or an Audyn Q4 (both are rated at 400 volts).
6.8 µF cap prices:
PE 1% $5.19
Solen $4.10
Audyn Q4 $3.74
Bennic 5% $3.05
PE 5% $2.75

For what it's worth, Dennis like using the Audyn Q4 caps because their leads are a bit longer and thicker. That makes assembly easier.
Remember that the caps with higher voltage ratings are larger in physical size. That may matter as you assemble a board with little space on it.
If that 100v cap is metalized polypropylene or mylar, its OK. Stay away from Non-polar electrolytic (NPE) caps. If I remember, they are usually rated at 100v and are cheap. Their capacitance ratings often vary by more than 10%. How many do you have to buy to get two that are both in spec? They just aren't worth it.

Thanks.

I've got PT and am going to stop by Pat's. Otherwise I'd be asking about everything else on that hp filter.

The only thing stopping me from getting my hands on the lp and bp filters was a missing 9/64 allen key: threaded inserts to hold the woofer down.

I set up the PE account. Going with the 5% stuff unless TLS or equivalent says otherwise.

BTW, I understand that 6.8 and 8.2 are okay to use for 7 and 8 values but are 7 and 8 available? I have one Solen cap that is 7 and rated for 400v. I can't seem to find a match for that. The film and foil caps do have the exact values but 2 caps comes pretty close to a c note. But that question is answered: 5% and I keep some money.

The LC meter? Gotta run. The pain awaits.

 

[Swerd]

Going with the 5% stuff unless TLS or equivalent says otherwise.

TLS has said he likes to use Solens. They're 5% and rated at 400v. He agrees with me that the most important thing a cap must do is to be within the specified capacitance value. Higher voltage ratings and exotic materials such a silver conductor and oil-filled dielectric are not important for speaker crossovers. They raise the price considerably.

An additional note about Audyn Q4 caps. Besides their sturdier leads, Dennis also likes them because they are bright red. He has customers who actually open his speakers to look over the xo board. Big red caps impress them . The Solens and PE/Bennics are black.

BTW, I understand that 6.8 and 8.2 are okay to use for 7 and 8 values but are 7 and 8 available? I have one Solen cap that is 7 and rated for 400v. I can't seem to find a match for that. The film and foil caps do have the exact values but 2 caps comes pretty close to a c note. But that question is answered: 5% and I keep some money.

I keep to the metalized polypropylene caps, and have never bought any of what PE calls "film and foil" caps.

Yes, 6.8 can substitute for 7, as 8 can for 8.2. If you have one Solen 7 µF and one other 6.8 µF cap, I'd go ahead and use them. It comes down to just how anal compulsive you are. Remember, when a crossover schematic calls for a cap of 7 µF, there is a ±10% latitude in the design. That means any cap value of 7 ± 0.7 µF = between 6.3 and 7.7 will be OK. The same goes for inductor values. Except, if you have an inductor with a larger value, you can always unwind some wire until it gives you the value you need. One of those LC meters is handy for that.

The LC meter?

I bought something similar from Amazon years ago, but that one should do.

I looked on Amazon and found several LC meters in the $30-35 range. One of them, a Mastech MY6243 sells for $35 and looks identical to the meter PE sells for $47 plus $8 shipping.

 

[everettT]

It comes down to just how anal....

Careful

 

[Alex2507]

If you have one Solen 7 µF and one other 6.8 µF cap, I'd go ahead and use them.

Not to save seven bucks times 2. But that's exactly what I have here, Solen @ 7 and 400 volts. The 6.8 is AEON rated for 250 volts.

Were you the one who worked on these ?!?

The 4 caps I have are from 3 different manufacturers and two voltage ratings. Those caps have been tortured by the looks of them.

Having two hp xo's with matching caps and resistors is something I want for those tweeters and it's what I need for peace of mind. When I repaired the xo before, I just wanted it to work and not blow up tweeters so I also have mismatched resistors of differing values and watt ratings. Now it's about making the boards symmetrical and once I get a 9/64 Allen, examining the bp and lp for design adherence and symmetry. PT got in the way of speakering today. Tomorrow, always tomorrow.

Careful

Ah ... I see you've done this before.

 

[Verdinut]

I have been using Solen caps for many years for crossovers, and they haven't been making 7µF ones for a long time if they ever have, as I've never seen one. The current value which they sell and have been selling for years has been 7.5µF in various voltage and characteristics. The 6.8µF value is also available.
Their capacitors are among the best on the market.

https://solen.ca/product-category/capacitors/

 

[Alex2507]

I looked on Amazon and found several LC meters in the $30-35 range. One of them, a Mastech MY6243 sells for $35 and looks identical to the meter PE sells for $47 plus $8 shipping.

I'm going to check my pawn shop and used tool store for a meter. That 6234 has a few people selling them at differing price and shipping costs. I must say, you win the bargain hunter of the thread award.

dlr of PETT who hosted the DIY GTG said the woofer tester 3 would give me inductance readings. I believe him and my question is whether it will give me a reading for capacitance as well, thereby eliminating the need for a multi meter. I should probably just buy both and quit penny pinching but budget. This is the part where I wish I had money instead of good looks.

Snooping around PE, I'm finding that all resistors are not created equal. The ones I used for my prior repair job were from a local electronics store (the last one in the state) and they're likely not the ones I should be using so PE to the rescue. The resistors in the current boards are joined up in odd series/parallel configurations to achieve desired values. I'll replace them all for $1.38 X 6. I'm excited about this.

I have been using Solen caps for many years for crossovers, and they haven't been making 7µF ones for a long time if they ever have, as I've never seen one. The current value which they sell and have been selling for years has been 7.5µF in various voltage and characteristics. The 6.8µF value is also available.
Their capacitors are among the best on the market.

https://solen.ca/product-category/capacitors/

I know ... (better yet) ... there is strong evidence that a parts bin was picked over for my xo components. I will continue this scavenging technique to cobble together a MBOW1 center after the mains get sorted.

I'm going to use Dayton Audio parts where I can for the price break and for the convenience of 1 stop shopping. It's interesting that the original builder used a slightly lower DCR coil of the ERSE line which I'll match for the future center. It's 18 ga as opposed to the 16 or 14 mentioned in Dennis' instructions but as Swerd pointed out, size matters.

For the moment, I'm working on a parts list while learning a little about saving a buck.

I popped a dental crown eating Swedish Fish so today is gonna be about my teef ... and then eating ... but speakering is on the horizon.

And it's a gonna be a nice a day ... I am surrounded by Italians. Good food, pretty women ... life is good.

 

[Swerd]

Were you the one who worked on these ?!?

The 4 caps I have are from 3 different manufacturers and two voltage ratings. Those caps have been tortured by the looks of them.

I categorically deny anything to do with them.

I'm going to check my pawn shop and used tool store for a meter. That 6234 has a few people selling them at differing price and shipping costs. I must say, you win the bargain hunter of the thread award.

That makes my day .

dlr of PETT who hosted the DIY GTG said the woofer tester 3 would give me inductance readings. I believe him and my question is whether it will give me a reading for capacitance as well, thereby eliminating the need for a multi meter. I should probably just buy both and quit penny pinching but budget. This is the part where I wish I had money instead of good looks.

I didn't know you had WT3. Yes, it does read inductance. I don't know if it can read capacitance, so check to see if it does.

For the moment, I'm working on a parts list while learning a little about saving a buck.

Be sure to include shipping costs. I usually see that PE caps cost less than what Madisound offers, and Madisound's inductors sell for less than PE's. Usually, the savings in Madisound's inductors is enough for me to ignore the lower prices of PE's 5% MPP caps. Despite that, I sometimes order all parts from one vendor or the other just because shipping can make a difference. It depends on what parts you're ordering.

 

[Verdinut]

I'm going to check my pawn shop and used tool store for a meter. That 6234 has a few people selling them at differing price and shipping costs. I must say, you win the bargain hunter of the thread award.

dlr of PETT who hosted the DIY GTG said the woofer tester 3 would give me inductance readings. I believe him and my question is whether it will give me a reading for capacitance as well, thereby eliminating the need for a multi meter. I should probably just buy both and quit penny pinching but budget. This is the part where I wish I had money instead of good looks.

Snooping around PE, I'm finding that all resistors are not created equal. The ones I used for my prior repair job were from a local electronics store (the last one in the state) and they're likely not the ones I should be using so PE to the rescue. The resistors in the current boards are joined up in odd series/parallel configurations to achieve desired values. I'll replace them all for $1.38 X 6. I'm excited about this.



I know ... (better yet) ... there is strong evidence that a parts bin was picked over for my xo components. I will continue this scavenging technique to cobble together a MBOW1 center after the mains get sorted.

I'm going to use Dayton Audio parts where I can for the price break and for the convenience of 1 stop shopping. It's interesting that the original builder used a slightly lower DCR coil of the ERSE line which I'll match for the future center. It's 18 ga as opposed to the 16 or 14 mentioned in Dennis' instructions but as Swerd pointed out, size matters.

For the moment, I'm working on a parts list while learning a little about saving a buck.

I popped a dental crown eating Swedish Fish so today is gonna be about my teef ... and then eating ... but speakering is on the horizon.

And it's a gonna be a nice a day ... I am surrounded by Italians. Good food, pretty women ... life is good.

For a passive crossover, the DCR of series inductors matter as it adds resistance in the signal path. For example, if you are building a two-way system, the inductor's DCR should ideally not be higher than 5% of the real nominal impedance of the woofer. As you know, manufacturers don't always publish accurate nominal impedances for their products. It's preferable to have access to a product like Dayton's DATS V.2 Speaker Testing Hardware for getting the real picture.

One of the reasons to limit the series resistance is that the total resistance between the amplifier and the woofer, that includes the speaker cable and the series inductor, have the effect of reducing the amplifier's damping factor apart from reducing the speaker's overall sensivity. As for a parallel inductor, the DCR is not as critical, and I normally use an AWG size 4 digits higher than that of the series inductor.

 

[Verdinut]

@Alex2507

If I'm not mistaken, you are now living in Canada? If so, I believe you could save a lot of money by ordering your xover parts direct from Solen. Shipping costs from PE are outrageous. When I ordered a replacement hardware for the DATS speaker tester, the shipping costs for the tiny hardware were 50% higher than the price of the item shipped!

https://solen.ca/product-category/capacitors/

 

[Swerd]

If I'm not mistaken, you are now living in Canada?

Alex lives in the USA.

 

[Verdinut]

Alex lives in the USA.

Now I know and I shouldn't forget about it. I thought I could help someone, but that will be for another opportunity.

Thanks for informing me.

 

[Swerd]

Now I know and I shouldn't forget about it. I thought I could help someone, but that will be for another opportunity.

Thanks for informing me.

It's easy to be mistaken about him. He did grow up in Canada, and frequently goes there to visit family.

 

[Alex2507]

Now I know and I shouldn't forget about it.

Dude, you mailed me the terminal strips.

Let me guess, you changed your mind about weed and suffered permanent memory loss after the first injection.

Thanks so much, BTW. I really can't wait to get to soldering.

Speakering took a back seat again. But when I get going ...

 

[Verdinut]

Dude, you mailed me the terminal strips.

Let me guess, you changed your mind about weed and suffered permanent memory loss after the first injection.

Thanks so much, BTW. I really can't wait to get to soldering.

Speakering took a back seat again. But when I get going ...

I had forgotten as to where you were living. Too many things on my mind at present. It's always nice to read you however.

 

[Alex2507]

Too many things on my mind at present.

Well, you did me a favor by sending those parts. Remembering that is my job.

I didn't know you had WT3.

I don't have one. I want one. I just don't want to dish out $150 for a WT3 and a meter. That stuff adds up quick and I'm never flush by the time I have time for this sort of thing. My financial situation is the only reason I'm not buying the $50 caps.

I categorically deny anything to do with them.

I'd love to know who all did what to them: Eastern European Code Book Cipher IV: Whose closet am I looking into?

I know this has all the aspects of A Speaker Horror but I'm still pretty happy I got into this mess. Living with these speakers and comparing them to a couple of other serious efforts at DIY, these have the best top end and their potential hasn't been fully tapped either. The bookshelf has foam on the walls backwards seemingly. Pictures will tell that tale. When Dennis said not to stuff the upper cabinet, it was in regards to a Ported MBOW1 but my Sealed MBOW1 3-Way upper cabinet was stuffed. I don't know if that matters. Anyway, I have 1" rigid fiberglass for the walls and some o' dat peel&seal and maybe an all-thread brace addition ... I'm getting ahead of myself.

Still need to dig out the bp and lp from the bass cab. PT first. Pic's coming. Exposing all ... a full frontal, and a not frontal. Pretty good chance of one of them internal pic's. How the hell do they get those shots?

 

[Swerd]

The bookshelf has foam on the walls backwards seemingly. Pictures will tell that tale. When Dennis said not to stuff the upper cabinet, it was in regards to a Ported MBOW1 but my Sealed MBOW1 3-Way upper cabinet was stuffed. I don't know if that matters. Anyway, I have 1" rigid fiberglass for the walls and some o' dat peel&seal and maybe an all-thread brace addition ... I'm getting ahead of myself.

You're talking about stuffing in the upper cabinet housing the mid range driver and tweeter of the MBOW1 3-way? And this particular cabinet was originally an MBOW1 2-way that was later converted to 3-way. Right?

It's my understanding that stuffing or lining a cabinet matters for bass performance. When Dennis said not to stuff the upper cabinet, he meant that what had been in the cabinet when it was a 2-way no longer applied once it was converted to a 3-way. Lining or stuffing doesn't have a major effect on the mid range driver because its high pass filter prevents it from doing any bass. I'm not sure if that means the cabinet interior should be left bare. I would guess that lining of some kind wouldn't hurt, and might benefit.

Do those separate sealed bass cabinets have poly stuffing?