T2 Crossover upgrade

[oldwood]

Is it possible to get instructions and parts to upgrade the Airmotiv T2 crossovers to the new T2+ crossover?

Forced isolation has me looking for projects

[pedrocols]

Good question!

[Boomzilla]

Well, Emotiva is unlikely to offer it. Why? Because it would void your warranty. If an owner would like to post the schematic for their T2+ crossover, then we could do similar upgrades ourselves, but that wouldn't do us any good if Emotiva also changed any of the driver parameters...

If you're willing to do without warranty, feel free to disassemble your existing T2 crossover. Upgrade any parts you want using higher grade stuff & let us know if you can hear any diff. That way, you know that the crossover you're modding works properly with your drivers and that the finished product should still meet factory specs.

If I were going to redo the crossover, I'd do the following:

Replace any non-polarized electrolytic caps with film caps of equal and identical value. In fact, I'd buy a flock of caps and hand-pick the ones closest to the values I'm looking for. I'd also buy one or two grades higher voltage-rated caps for greater durability and less drift.
Replace any carbon or composite resistors with honking-high-wattage metal films - and again, I'd buy a flock of resistors and hand-pick the ones closest to the values I'm looking for. I'd also buy one or two grades higher power-handling resistors for the same reasons as above.
Replace any ferrite-core chokes with air-core ones (Might have to use some glue to secure the bigger air-core coils)
I'm already satisfied with the speaker terminals, so no prob there.

Would it make an audible difference? Maybe, maybe not...

[oldwood]

Mar 23, 2020 11:00:57 GMT -5 Boomzilla said:

Well, Emotiva is unlikely to offer it. Why? Because it would void your warranty. If an owner would like to post the schematic for their T2+ crossover, then we could do similar upgrades ourselves, but that wouldn't do us any good if Emotiva also changed any of the driver parameters...

If you're willing to do without warranty, feel free to disassemble your existing T2 crossover. Upgrade any parts you want using higher grade stuff & let us know if you can hear any diff. That way, you know that the crossover you're modding works properly with your drivers and that the finished product should still meet factory specs.

If I were going to redo the crossover, I'd do the following:

Replace any non-polarized electrolytic caps with film caps of equal and identical value. In fact, I'd buy a flock of caps and hand-pick the ones closest to the values I'm looking for. I'd also buy one or two grades higher voltage-rated caps for greater durability and less drift.
Replace any carbon or composite resistors with honking-high-wattage metal films - and again, I'd buy a flock of resistors and hand-pick the ones closest to the values I'm looking for. I'd also buy one or two grades higher power-handling resistors for the same reasons as above.
Replace any ferrite-core chokes with air-core ones (Might have to use some glue to secure the bigger air-core coils)
I'm already satisfied with the speaker terminals, so no prob there.

Would it make an audible difference? Maybe, maybe not...

It is my understanding that the difference between the T2 and the T2+ was the notches in the cabinet face (don't care) and the new crossover that gives a slightly smoother transition between high and mid frequencies. Am I mistaken in this?

I don't think the cost of the crossovers should be a huge issue and I am not overly concerned about the warranty issue. I regard the length of the warranty a manufacturer supplies with their product more of a indicator of their confidence in the product than anything else.

I was hoping I could just buy the same crossover Emotiva used in the T2+ and install it.

Thanks for the input,

Gerry

[Boomzilla]

If there are truly no differences in the drivers, Gerry, you might contact Emotiva and just ask if they'd sell you a T2+ pair of crossovers. The worst they can do is say "no." And if they DO say "no," then ask if they'd share the schematic with you for the crossover changes.

If I had a pair of T2+ models, I'd be happy to extract one crossover and send you photos & a schematic, but my speakers, like yours, are the original T2s - not the new ones.

Best of luck, and let us know what you find out!

Boomzilla

[oldwood]

It would be nice to hear some input from someone who has had a blind A - B listening test with the T2 vs the T2+ before heading down this road but I will probably call Emotiva just to find out if it is possible.

I will let you know what I find out.

Thanks

[klinemj]

Mar 23, 2020 13:16:09 GMT -5 oldwood said:

It would be nice to hear some input from someone who has had a blind A - B listening test with the T2 vs the T2+ before heading down this road but I will probably call Emotiva just to find out if it is possible.

I will let you know what I find out.

Thanks

By Emotiva's own admission, the sonic differences are minimal, so frankly - doesn't seem worth the effort to me.

Mark

[oldwood]

By Emotiva's own admission, the sonic differences are minimal, so frankly - doesn't seem worth the effort to me.

Mark

I remember reading the comments in regard to the crossover change but have not been able to find them. If the cost is not too high I would pursue it even if the changes are subtle. Just that kind of a lunatic

[Boomzilla]

Better speakers for minimum $$$? What's not to like?

[oldwood]

Mar 23, 2020 15:25:24 GMT -5 Boomzilla said:

Better speakers for minimum $$$? What's not to like?

Yes that is my view also. I like to fiddle and tweak so that is a side benefit.

[garbulky]

I have a feeling that if you call and ask to speak to one of the engineers, they would be willing to give you the information as long as you are willing to be discrete.

[KeithL]

I would also mention that, if your system has room correction, it may quite possibly "adjust away" any audible difference.

As someone else already said, the benefits would be minimal, and you'd void your warranty... and we really don't want to get into the kit business.

(I'm sure that, eventually, someone will take one apart and take pictures of the crossover... we don't sand the values off the parts. )

However, if you really want a project building speakers, then wouldn't it make more sense to design your own from scratch.

(Or build your own, from scratch, from instructions.)

Parts-Express offers some excellent kits and projects...  (  projectgallery.parts-express.com/category/speaker-projects/  )

And Zaph Audio offers several projects at different levels of difficulty...  (  www.zaphaudio.com/  )

Mar 23, 2020 13:59:29 GMT -5 oldwood said:

By Emotiva's own admission, the sonic differences are minimal, so frankly - doesn't seem worth the effort to me.

Mark

I remember reading the comments in regard to the crossover change but have not been able to find them. If the cost is not too high I would pursue it even if the changes are subtle. Just that kind of a lunatic

[oldwood]

"I would also mention that, if your system has room correction, it may quite possibly "adjust away" any audible difference. As someone else already said, the benefits would be minimal, and you'd void your warranty... and we really don't want to get into the kit business.

(I'm sure that, eventually, someone will take one apart and take pictures of the crossover... we don't sand the values off the parts. )"

I don't us room correction. As far as the extent of the benefits, I thought someone at Emotiva must have thought it sounded better or it would not have been changed. How much better is I am sure subjective. I was looking for a part for a current production speaker, not a speaker kit so I don;t understand the comment about not wanting to get into the kit business.

"However, if you really want a project building speakers, then wouldn't it make more sense to design your own from scratch.
(Or build your own, from scratch, from instructions.)"

I think there is a lot of road between changing out a crossover and designing and building a set of speakers. I have recently retired and sold the cnc router and other panel processing machinery and have no desire to start building speaker cabinets with a table saw.

In the end the takeaway is Emotiva will not sell the part and it would be too much work to find the specs on the T2+ crossover and build one for 2 speakers. 

Thanks,

Gerry

[leonski]

The advantage of AIR CORE over ferite core Inductors is in power handling. Air Core simply do NOT 'saturate' the same as a metalic cored inductor.

You will ALSO find a difference in DCR (DC Resistance) which is like changing a resistor in a crossover so equipped. And it'll change the crossover freuqnecy a LITTLE. Depends.

Caps, as Boom indicates, Can be improved. Me? I'd worry about tolerance. Most caps might be 20%. You can find and source 10% and in rare instances 5% caps.

IMO? the BEST approach would be to get the crossover specs from EMO. Crossover points and slopes. THAN gut the crossover, and replace it with a MiniDSP and multiple amps.

An ACTIVE line level crossover will be quite a gain and you can THAN play from that point forward.

[KeithL]

All true... although I should point out a few interesting things.

First off, while ferrite core inductors can be saturated, which can cause nonlinearities at high power levels...

They require far less length of wire for a given inductance...

This means that they can be made smaller and with lower resistance than an equivalent air core inductor.

In an inductor lower DC resistance is consider to mean that it is a higher quality inductor.

This can potentially result in better damping (for example in a woofer).

I should also not that the components in a passive crossover interact with the electrical characteristics of the drivers.

Therefore, simply measuring them, and "punching in the same values" in an active crossover, may not yield the exact same results.

So, if you really want to redesign the speakers, then you really should measure the drivers, then calculate new values from scratch.

Mar 30, 2020 12:08:24 GMT -5 leonski said:

The advantage of AIR CORE over ferite core Inductors is in power handling. Air Core simply do NOT 'saturate' the same as a metalic cored inductor.

You will ALSO find a difference in DCR (DC Resistance) which is like changing a resistor in a crossover so equipped. And it'll change the crossover freuqnecy a LITTLE. Depends.

Caps, as Boom indicates, Can be improved. Me? I'd worry about tolerance. Most caps might be 20%. You can find and source 10% and in rare instances 5% caps.

IMO? the BEST approach would be to get the crossover specs from EMO. Crossover points and slopes. THAN gut the crossover, and replace it with a MiniDSP and multiple amps.

An ACTIVE line level crossover will be quite a gain and you can THAN play from that point forward.

[leonski]

When contemplating just such an upgrade for my Magnepans, I REALLY researched inductors. And I mean to insane levels. But that's me.

First thing? You need to know the wire size of the inductor to be replaced. An aircore inductor with larger wire will have less resistance PER FOOT.

Than you need to research a calculator and start running some simulations. DO NOT depend on someones 'off the shelf' inductor. It will NOT be optimum.

A 'perfect' inductor has the SAME NUMBER of layers as turns per layer. This results in a coil which is SQUARE in cross section.

I ran a dozen or more calculations of inductors and finally found an AIRCORE to match the stock iron/ferite core which comes with the panel. Maggies are notoriously Low Sensitivity

and at the highesst levels consume lots of power. So It may pay to go to aircore insuch a situation.

I was able to match the stock inductor's DCR using either 13ga or 14 ga VS the stock 16ga. I was able to work core size (diameter of core) and OUTER diameter to achieve the SAME number

of winds per layer as layers. Perfect. I was also able to make this work using STOCK PVC sizes to provide a winding form. Add Expoxy as you wind and than remove from forms and BAKE

in a warm oven for a coupe hours. Do NOT exceed the insulation temp rating. Maybe 105c?

Lower resistance is Not Necessarily a indicator of higher quality. The inductor in my panels is listed as 0.40ohms. And it was difficult to find one that wasn't much lower. 1/2 the spec'd value

was typical. I had to go to some trouble to noodle an inductor within 5% of stock. A number I simply chose out of the air. And found it was doable.


That being said, Keith makes a VERY valid point. Too bad few have the background to First Measure (itself somewhat of a black art for the DIY guy) than decide on 'what is best' for crossover

points and slopes. That's why I would recommend startign with whatever the designer specified. And that's what makes te MiniDSP so attractive. You can even experiment in some cases with

FIR filters which have NO PHASE SHIFT thru the passband. My panels have a 1st order high pass and 2nd order low pass. They put's em 90 degrees apart. And automatically constrains placement / orientation.

If I had no phase shift? Some possibiities might open up. I'd have to DO it and than listen......

[KeithL]

I would add one thing....

If there is already a resistor in series with an inductor, and you plan to match the original, then you gain little by reducing the DC resistance.

Likewise, if there was originally no series resistor, and you get a coil with a lower DCR, you can always ADD a series resistor to match the original DCR.

HOWEVER, if that inductor is in series with the woofer, a lower overall series resistance value will give you a higher damping factor.

In that case, the difference you get by NOT matching the original MAY be an improvement, or it may not...

But, in that case, exactly matching the original may not be the best way to go.

This is why it really makes sense to do ALL the calculations.

And here's another interesting tip if you're planning to DIY the project.

It can often be difficult to find a coil that's just the right value... especially if you want an odd value...

However, many low cost digital multimeters can measure inductors quite accurately.

And a straight wire has very little inductance compared to a coil...

So.....

If you cannot find the correct value, or the value you need is especially expensive, then buy a coil with a higher inductance value than you need....

Buy one with the next higher standard value....

And simply unwind and discard turns until it reaches the correct value.

If you connect the meter to both ends, then unwind the wire straight out as you unwind it, the wire you've unwound will have near zero inductance...

So you don't have to cut off the excess and reposition the meter until you get close to your target value.

(Obviously you cannot do this if you have a hard epoxy coated coil.)

Mar 30, 2020 22:02:31 GMT -5 leonski said:

When contemplating just such an upgrade for my Magnepans, I REALLY researched inductors. And I mean to insane levels. But that's me.

First thing? You need to know the wire size of the inductor to be replaced. An aircore inductor with larger wire will have less resistance PER FOOT.

Than you need to research a calculator and start running some simulations. DO NOT depend on someones 'off the shelf' inductor. It will NOT be optimum.

A 'perfect' inductor has the SAME NUMBER of layers as turns per layer. This results in a coil which is SQUARE in cross section.

I ran a dozen or more calculations of inductors and finally found an AIRCORE to match the stock iron/ferite core which comes with the panel. Maggies are notoriously Low Sensitivity

and at the highesst levels consume lots of power. So It may pay to go to aircore insuch a situation.

I was able to match the stock inductor's DCR using either 13ga or 14 ga VS the stock 16ga. I was able to work core size (diameter of core) and OUTER diameter to achieve the SAME number

of winds per layer as layers. Perfect. I was also able to make this work using STOCK PVC sizes to provide a winding form. Add Expoxy as you wind and than remove from forms and BAKE

in a warm oven for a coupe hours. Do NOT exceed the insulation temp rating. Maybe 105c?

Lower resistance is Not Necessarily a indicator of higher quality. The inductor in my panels is listed as 0.40ohms. And it was difficult to find one that wasn't much lower. 1/2 the spec'd value

was typical. I had to go to some trouble to noodle an inductor within 5% of stock. A number I simply chose out of the air. And found it was doable.


That being said, Keith makes a VERY valid point. Too bad few have the background to First Measure (itself somewhat of a black art for the DIY guy) than decide on 'what is best' for crossover

points and slopes. That's why I would recommend startign with whatever the designer specified. And that's what makes te MiniDSP so attractive. You can even experiment in some cases with

FIR filters which have NO PHASE SHIFT thru the passband. My panels have a 1st order high pass and 2nd order low pass. They put's em 90 degrees apart. And automatically constrains placement / orientation.

If I had no phase shift? Some possibiities might open up. I'd have to DO it and than listen......

[vcautokid]

You are going to get more out of DSP processing than any slight modifications you perform anyway. Room correction and room treatment and so on are a good way to get the speakers where they need to be. Also diving inside the speakers does void your warranty. Plain not worth it. You build your own from scratch pretty darn reasonably as a do it at home project. Make some speakers for another room, experiment to your heart's content. Hifi was invented this way. Parts Express and others will get you the parts needed for that home project build.

[leonski]

25 yearss ago And Change, a buddy built a pair of speakers from the Radio Shack cookbook. It was a double ported design. Woofer enclosure was ported AND a port into another enclosure which also had a port. Really good bass considering the 8" woofer.
Largish and heavy design for an 8" speaker. But it was well worth it.

VC has point. But I make it to be that the ROOM is primarily what you are hearing, not the speaker. A very good speaker in a poor room will still sound awful.

BiAmp thru an external line level (passive OR active) crossover addresses a different issue.