Question about updating caps

[Squishman]

I bought another pair of walnut Minimus 7's to use as rear heights. Walnut because it'll be easier to bracket into the wood as opposed to the metal cab version with the super tiny screw holes and they are lighter, which might be better to hang. With my other Minimus 7's, I had upgraded the xovers using kits or 2-way replacement xovers from Amazon. All sound great. This set, one terminal plate (which will be changed also!) was upside down, so I knew someone had done something or other to it, so I asked him. This was his reply: "Hello, the crossovers on these realistic speakers only have one capacitor and I had some MPT film caps of the same value on hand and just put them in as an experiment. The speakers were working fine before but in my opinion they sound a little bit better with the new caps. "
My question is: is that all that is nessesary to upgrade them? I am not a speaker or crossover expert. I just know how to solder and follow instructions. So I was wondering if what he did would get them up to snuff. Attached is a google photo of original Minimus 7 crossovers in case that helps answer my question. I don't have them until next week, but of course, I will be doing an A/B comparison with my existing upgraded ones.

 

[Squishman]

Btw, I have an ebay search saved for 8 ohm Miller and Kreisel tweeters model number 17500 which I have in three pairs of these speakers. I decided to do an A/B comparison stock tweeter vs M&K with the same Amazon crossover. No comparison playing some mono Beatles music fading left to right and back. Maracas, etc just stand out in the M&K and with the stock tweeter, not so much. Wow, big difference. So I bought another pair. I need to find more fiber board to make mounts now. Here is a photo of one of my front heights that I have had for over 5 years.

 

[TLS Guy]

I bought another pair of walnut Minimus 7's to use as rear heights. Walnut because it'll be easier to bracket into the wood as opposed to the metal cab version with the super tiny screw holes and they are lighter, which might be better to hang. With my other Minimus 7's, I had upgraded the xovers using kits or 2-way replacement xovers from Amazon. All sound great. This set, one terminal plate (which will be changed also!) was upside down, so I knew someone had done something or other to it, so I asked him. This was his reply: "Hello, the crossovers on these realistic speakers only have one capacitor and I had some MPT film caps of the same value on hand and just put them in as an experiment. The speakers were working fine before but in my opinion they sound a little bit better with the new caps. "
My question is: is that all that is nessesary to upgrade them? I am not a speaker or crossover expert. I just know how to solder and follow instructions. So I was wondering if what he did would get them up to snuff. Attached is a google photo of original Minimus 7 crossovers in case that helps answer my question. I don't have them until next week, but of course, I will be doing an A/B comparison with my existing upgraded ones.

Those Minimus speakers have simple first order crossovers with 6db roll off on the woofer and tweeter. So there is a lot of overlap. I would bet they were designed with much effort or thought, shown throw together to make the the cheapest crossover possible. The used to be popular because they were cheap.

 

[Squishman]

Those Minimus speakers have simple first order crossovers with 6db roll off on the woofer and tweeter. So there is a lot of overlap. I would bet they were designed with much effort or thought, shown throw together to make the the cheapest crossover possible. The used to be popular because they were cheap.

Thx for your reply! So I may be better off with the Amazon xover I imagine. You tested one M7 with the Amazon xover and it was fine if you recall. So I will get another pair of those crossovers if you agree. Although, I know little about it, it seems that the Amazon ones are way more elaborate. https://www.amazon.com/gp/product/B016FBNNCY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[TLS Guy]

Thx for your reply! So I may be better off with the Amazon xover I imagine. You tested one M7 with the Amazon xover and it was fine if you recall. So I will get another pair of those crossovers if you agree. Although, I know little about it, it seems that the Amazon ones are way more elaborate. https://www.amazon.com/gp/product/B016FBNNCY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I just measured the impedance curve. The specs on Amazon are not correct, that is not as described. It is a first order 6db low pass and 12db high pass. It claims to be at 3,500 Hz. The issue is that crossovers can not be generic and have to be individually designed for the drivers concerned.

 

[Squishman]

I think the A/B test then will be both with M&K tweeters, one with this seller's cap install and the other with the Amazon xover.

 

[Squishman]

I just measured the impedance curve. The specs on Amazon are not correct, that is not as described. It is a first order 6db low pass and 12db high pass. It claims to be at 3,500 Hz. The issue is that crossovers can not be generic and have to be individually designed for the drivers concerned.

I think the A/B test then will be both with M&K tweeters, one with this seller's cap install and the other with the Amazon xover.
I wish I could get the crossover kit that I got on eBay years ago. He sold hundreds of them and then disappeared a few years back. I think that guy knew what he was doing for these speakers.

 

[TLS Guy]

I think the A/B test then will be both with M&K tweeters, one with this seller's cap install and the other with the Amazon xover.
I wish I could get the crossover kit that I got on eBay years ago. He sold hundreds of them and then disappeared a few years back. I think that guy knew what he was doing for these speakers.

Here is a circuit from a DIY designer, and he has measurements to show it is a good crossover. The circuit was originally published on Adiokarma I understand. Of course that would require the original tweeters, as changing tweeters would require a different design. This circuit is a second order high and low pass, with a pad to the tweeter.

The above circuit would be easily constructed. According to this article there was no crossover in the Minimus 7. It just had a cap to the tweeter.

 

[Squishman]

Here is a circuit from a DIY designer, and he has measurements to show it is a good crossover. The circuit was originally published on Adiokarma I understand. Of course that would require the original tweeters, as changing tweeters would require a different design. This circuit is a second order high and low pass, with a pad to the tweeter.

The above circuit would be easily constructed. According to this article there was no crossover in the Minimus 7. It just had a cap to the tweeter.

Some of this is Greek to me, but this is the back sheet in the installation instructions from the ebay seller. He is the guy btw, who originally told me about the M&K tweeters. In fact I bought a set from him after he sent me two sets free of charge for his metal cone kits which have a different crossover that he designed. One of my metal cone kits is for Minimus 77's, which have 5" woofers. The other metal cone kit is for M7's which are 4". This page of the instruction sheet is for his original Radio Shack driver crossover, not his metal cone kit. I hope the resolution is ok with the attachment.

 

[TLS Guy]

Some of this is Greek to me, but this is the back sheet in the installation instructions from the ebay seller. He is the guy btw, who originally told me about the M&K tweeters. In fact I bought a set from him after he sent me two sets free of charge for his metal cone kits which have a different crossover that he designed. One of my metal cone kits is for Minimus 77's, which have 5" woofers. The other metal cone kit is for M7's which are 4". This page of the instruction sheet is for his original Radio Shack driver crossover, not his metal cone kit. I hope the resolution is ok with the attachment.

There is nothing there to say it is a good crossover. Those are just impedance curves. What I see is a generic second order high and low pass crossover and no zobel as the designer claims.

You do have to know what you are doing to design a good crossover, and ALL have to be specific to the drivers involved.

I have confirmed that those speakers as they left the factory had NO crossovers.

 

[Squishman]

There is nothing there to say it is a good crossover. Those are just impedance curves. What I see is a generic second order high and low pass crossover and no zobel as the designer claims.

You do have to know what you are doing to design a good crossover, and ALL have to be specific to the drivers involved.

I have confirmed that those speakers as they left the factory had NO crossovers.

Thanks for checking that. I never knew that had no crossovers! Hoping they sound good as is... or when I install the tweeters that is.