# T/S parameters and impedance sweep of the new Stereo Integrity TM65 mKiv



## cman (Aug 24, 2020)

I have posted the measured values with my Dayton DATS... the lighter box is my WinISD window with the specs taken directly off of Stereo Integrity's website.

They match very closely, especially considering the driver is not broken in at all.. I expect once I have broken them in that the FS will lower slightly and it will be even closer to the published parameters.

Still even how it is right now, it is pretty close to the listed parameters compared to some other drivers that I own, (and the fact that the DATS can be a little finnicky at times compared to more expensive measurement devices)

I am extremely impressed with the build quality, not anything half way done or rushed like messy (or under or over applied) glue, dust cap is aligned nice, glue is where it is supposed to be on the surround, spider, etc. It gives me confidence that the important components like the voice coil are properly aligned inside the gap which is something you cannot see.. but sometimes when i see sloppy assembly from certain manufacturers it makes me think "damn i hope the coil is not crooked or offset" So, in this case, seeing that the outside looks nice and the fact that the t/s parameters are close to the manufacturers, makes me feel like the quality control is good.

Also pretty impressive is the shallow mounting depth.. this driver has a lot to offer considering how shallow it is.. it has a 2" coil, aluminum cone, low inductance (i actually measured lower than advertised inductance!) so yeah it is pretty dang cool considering the price.


Obviously something I have not done which is very important, will be frequency response. The data Stereo Integrity has posted looks great, and I will be using this as a mid bass in a 3 way so i don't care about anything over 500hz.. but I always like to see real 3rd party testing not just what the manufacturer shows just because us in the car audio industry have been lied to by so many companies I don't believe anyone until I see 3rd party testing.. but in this case it looks like the data Stereo Integrity is showing is accurate, granted I have not tested the frequency response.. since what I have measured matches.. I would be inclined to say the xmax and FR that SI posted on their website is also accurate.

I'm sure somebody will post 3rd party frequency response (and maybe even klippel if somebody can talk Erin H into testing a pair) once more people start to get these in their hands. I dont have a good way to measure it before i throw these in my car.. but once i do that i will take a FR measurement.


Anyways, Stereo Integrity did not know I was going to measure this nor do they know who I am.. this is just a random pair I bought.. so nice job as far as I am concerned (considering the data I have right now). I will update this post once I get them in my car.


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## cman (Aug 24, 2020)

having some technical issues... i am re uploading the pics now for some reason they disappeared..








































OK, looks like the pics are back, here are a few more


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## Racer71 (Nov 24, 2021)

mine showed up Thursday and I put them in Friday eve. I’m still learning rew etc so I don’t have any measurements to post yet. They do look and seem very nice, mine is a three way setup as well. All I’ve done this far is set crossovers in the helix software, I have a long way to go yet.


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## Racer71 (Nov 24, 2021)

A few pics I snapped before install.


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## Nathaniel117 (12 mo ago)

Whats the xmax? The way erinscorner would measure it OR there abouts. Thnx for any help.


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## SloVic (Oct 1, 2016)

Don't think the OP has the means to measure xmax. Need expensive specialized equipment for that.


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## ballz50401 (Apr 14, 2018)

I'll share my measurements from my pair of TM65 mkIV's with the DATS V2. Each photo is before and after break-in. These guys are super quiet while breaking them in around the 20-40 Hz range compared to the mkI's and mkII's.


Driver #1











Driver #2


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## JI808 (Nov 20, 2013)

cman said:


> I have posted the measured values with my Dayton DATS... the lighter box is my WinISD window with the specs taken directly off of Stereo Integrity's website.
> 
> They match very closely, especially considering the driver is not broken in at all.. I expect once I have broken them in that the FS will lower slightly and it will be even closer to the published parameters.
> 
> ...


The specs on Stereo Integrity's drivers comes from Klippel tests.


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## fish (Jun 30, 2007)

Do any of you guys who've installed these have any initial listening impressions you'd like to share? For $400, I'm on the fence with these right now.


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## bbfoto (Aug 28, 2005)

fish said:


> Do any of you guys who've installed these have any initial listening impressions you'd like to share? For $400, I'm on the fence with these right now.


Sorry, I can't offer any experience or listening impressions for this latest version.  But are you planning to swap out the 18Sound 6nd430 midwoofers in your current 2-way front system listed in your signature for the TM65 MK IV in the OEM front door locations?

Even without having heard these, I believe that their performance would be excellent given the specs and quality of construction alone. And I have fairly high confidence in the specs and performance since they were tested on the Klippel.

At their introductory or pre-order pricing, I believe these were an absolute no brainer. And even at $400 for the pair, I believe you'd have a very hard time finding other drivers with this level of performance combined with the features and shallow mounting depth for less than 2x the price or more (Audiofrog GB60, for instance). That's also taking into account that these are designed for a typical OEM car door location in terms of specs and environmental protection factors, though the 6nd430 also had the environmental protection aspect covered as well.

My ONLY issue and reservation with most of the Stereo Integrity products is their production longevity and stock/supply issues. They are not like a standard Peerless, Vifa, Scanspeak, or even mainstream car audio manufacturer's component set where you had confidence that they would still be available in 5+ years.

As is clear, these are on their 4th iteration. And while the constant improvement of the driver design is commendable and appreciated, there were large gaps in the availability of each subsequent version, until ultimately each was finally discontinued.

Future availability for each was a constant gamble unless you ordered several sets to have as backup or future installs during the pre-order sale.

That meant that if you had planned your system around using these drivers (or S.I.'s other drivers in the lineup), you might have found out the hard way that they were no longer in stock or available by the time you were ready to order, and you might be SOL.

The same applied to if you had an accidental failure, manufacturing defect, or damage at the time of installation (the surrounds on at least one of the previous versions would tear easily if you didn't use the exact screws and washers and take extreme care during installation).

In any of those instances, you were extremely lucky if you could still order a replacement due to stock shortages or that model being discontinued.  So you might get stuck with having to buy a complete set of the newer version and being left with a pretty much useless single orphaned driver, or going with something completely different which might mean additional work to accommodate mounting the different drivers.

The in-stock/out-of stock guessing and timing game was always frustrating to me. But so far that seems to not be as much of an issue lately, and I hope that continues!

Otherwise, I would have no reservations in buying and using these as they were intended.

I was hoping to pick up a pair of this latest iteration while they were still at the pre-order pricing, but the timing of my various installs just wasn't right. I still might order a pair even though I have no immediate use, because I do think that they would offer SOLID performance.

To be fair, I haven't used the 6nd430 either, so have no idea regarding their performance IRW use, though it also looks "good on paper". But maybe not as good in terms of playing down close to their Fs in a typical I.B. car door, considering their low-ish Qts.

What are the 6nd430 lacking?


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## JI808 (Nov 20, 2013)

bbfoto said:


> Sorry, I can't offer any experience or listening impressions for this latest version.  But are you planning to swap out the 18Sound 6nd430 midwoofers in your current 2-way front system listed in your signature for the TM65 MK IV in the OEM front door locations?
> 
> Even without having heard these, I believe that their performance would be excellent given the specs and quality of construction alone. And I have fairly high confidence in the specs and performance since they were tested on the Klippel.
> 
> ...


I spoke with Nick about the upgrades over time. No other company does this. What they do is make different lines of the same size driver. Nick would rather make one of each size. But he takes pride in the stuff and is always wanting to make it better. If you're on this forum, it's likely we're all like that - "good" never good enough. Always refining.

So anyway, I talked to him about the Mk I, Mk II, Mk III...and so on and told him to finally be done with the constant upgrades. The TM65 MkIVs are great drivers. No need to change them. 

He agreed and said that the product line-up now (TM65 MkIV, M3 Carbon, and M25 tweeters) won't be seeing revisions in the future. These are the drivers that you'll see in those sizes going forward.

For anyone worried about a replacement for an older series, I'm sure you'd just end up with the new, better performing stuff.


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## JI808 (Nov 20, 2013)

fish said:


> Do any of you guys who've installed these have any initial listening impressions you'd like to share? For $400, I'm on the fence with these right now.


I love them. I built the Stereo Integrity Audi and have given tons of demos to people in it. Between Nick and I one of the constants we get in feedback is "Man, those midbasses are doing some work".

There's a guy on the forum, *dmparker5725, *that has the TM65Mk IVs and the new M25 tweets in his A6. We were all at Bertholomey's SQ meet. He had been having issues with his tune and Nick voluntold  me to tune the car for him.

So in about 20 minutes I had a tune on the car that he loved. I forget who it was at that meet, but someone got in Damien's car and was so impressed with the TM65s that they bought some at the meet.

I typically run them 70-2500 with the M25s and 70-300 with the M3s. All with LR4s.


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## fish (Jun 30, 2007)

bbfoto: Like most of us on here, it's just the urge to try something different... maybe finding something better suited for the application. I agree, the specs look very well-suited for a car door, but I like to read reviews/comments before purchasing just about anything. Regarding the 6nd430s, they're phenomenal throughout the midrange & have them playing up to 1k with the GS25s taking over from there. I prefer the lower midrange coming from a larger speaker to provide more body down low. Like it's been mentioned by a few before me, this driver does fall a little short below 100-120hz, so that's the primary reason for the urge to try something else. My doors are pretty dead, so I think a stronger midbass driver could be beneficial. You made some very valid points for both sides of the argument with some great insight.


JI808: I appreciate you chiming in. That's some great news from your discussion with Nick saying the current drivers in the lineup are gonna be around for a while. That definitely helps me solidify my choice. Thank you for your personal experience with these as well!


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## bbfoto (Aug 28, 2005)

fish said:


> bbfoto: Like most of us on here, it's just the urge to try something different... maybe finding something better suited for the application. I agree, the specs look very well-suited for a car door, but I like to read reviews/comments before purchasing just about anything. Regarding the 6nd430s, they're phenomenal throughout the midrange & have them playing up to 1k with the GS25s taking over from there. I prefer the lower midrange coming from a larger speaker to provide more body down low. Like it's been mentioned by a few before me, this driver does fall a little short below 100-120hz, so that's the primary reason for the urge to try something else. My doors are pretty dead, so I think a stronger midbass driver could be beneficial. You made some very valid points for both sides of the argument with some great insight.
> 
> 
> JI808: I appreciate you chiming in. That's some great news from your discussion with Nick saying the current drivers in the lineup are gonna be around for a while. That definitely helps me solidify my choice. Thank you for your personal experience with these as well!


Cool. I think they would be an upgrade in terms of their increased potential in midbass output where the 6nd430 is lacking. Good midbass output has always been the hallmark of the TM65 series. 

I also like where you currently have the X/O to the GS25, because...

The ONLY thing that I didn't like seeing in the measurements for the TM65 MK IV in regards to using it in a more typical 2-way with a 1" to 1"-1/8" tweeter is that relatively significant blip in the impedance curve around 1.2k-1.3k, which indicates a resonance and is right in a very sensitive range of our hearing.

But in your setup with the GS25 you have the wiggle room in the X/O region to minimize it's potential audible effects, *if* there are any. Again, unfortunately I have no personal experience with this version of the TM65...yet. In a typical 3-way front setup it would be a non-issue.

To be fair, many good 6.5" midwoofers have a similar impedance blip and resonance in this area, though usually not quite as pronounced, and it is an inherent trait due to the diameter of the driver. IIRC, it is most often attributed to the intersection of cone/surround transition.

If you are using the Audiomobile MASS 2212 subwoofer in this system, you also might use *ErinH*'s suggestion to try using your subwoofer to help supplement the midbass response...


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