External crossovers - any improvement in SQ?

[worrasf]

I have just acquired a pair of new Type 24 crossovers for my Rogers JR149's.
As there is absolutely nothing wrong with the original crossovers which i just recapped I am in no tearing hurry to swap them over (so why did you lay out £95 you ask? :mental: because they are difficult to come by new and I just had to have them and you never know they may sound better I reply :eyebrows:)

So I got to thinking - how about I put them in some nice new Hammond cases and mount them externally rather than direct under the cabinet?

A small web trawl gives mixed opinions on whether there is any sonic improvement to be had with external crossovers - some saying it reduces distortion from vibration in the inductors/capacitors others maintaining this is BS and there is no SQ improvement to be had.

So, anyone done this? Any opinions either way?

Steve

[Reid Malenfant]

With a crossover mounted inside the enclosure being battered by the sound from the rear of the bass/mid driver I reckon it would be better to use an external crossover. But yours isn't actually inside the main part of the enclosure so that's moot.

Your recapped vesion should sound better imo even where it is now :)

[YNWaN]

One of the capacitor manufacturers did a lot of research (a couple of years ago) into the benefits of mechanically damping capacitors (as some of their customers were both doing it and requesting it). They found no evidence that the capacitor was effected by vibration emitted from drive units and panel resonance. However, they did find evidence that the capacitor itself vibrated as the signal passed through it - so, damping the capacitor did make a difference, but not for the reasons thought.

If there is any benefit to removing X-overs, it is unlikely to be because they are no longer being bombarded by sound from the drivers (IMHO). I think it is more likely that they are no longer picking up mechanical vibration from the cabinet walls (which can be of quite a high amplitude at some frequencies).

[The Grand Wazoo]

It's an experiment that's not usually so easy to reverse in order to make a meaningful comparison, but now having two sets of crossovers, you seem to be uniquely placed to do just that.

[sq225917]

Improvements are more likely to come from enhanced layout in the XO, orientation of coils etc than from reduction in drive unit induced vibration which has never proven to exert a measurable effect on the sound.

[YNWaN]

I would agree

[Reid Malenfant]

Improvements are more likely to come from enhanced layout in the XO, orientation of coils etc than from reduction in drive unit induced vibration which has never proven to exert a measurable effect on the sound.
It hasn't been disproven either :eyebrows: I'd suggest that reducing vibration certainly wouldn't be a bad idea as I'm sure we have all heard of that bad boy called microphony. However as I already stated they aren't in the cabinet proper so these effects kind of go out the window.

Coil orientation doesn't look to be too bad on those crossovers, while it'd be great if they were all at 90 degrees to each other the sheer number of them looks like it'd make that next to impossible. Maybe some screening might be a better idea.

[worrasf]

Thanks for the input chaps - just heard back from Graham Hartle who built the crossovers and like you he reckons no advantage in placing externally. I'll swap them in at weekend if time and then try and compare with the originals although Graham advises they will take some time to sound their best do might all be a bit subject to the vagueries of memory
Steve

[nat8808]

How about magnetic interaction between the driver magnets and coils and the inductors in the x-over? Maybe also effecting fields on the capacitor plates and effecting how they work?

Personally I thought that was the reason for externalising them (plus room for a better build).

Unless the extra wire between speaker and x-over outweighs benefit, I don't see you have anything to loose sonically.

[sq225917]

It hasn't been disproven either :eyebrows: I'd suggest that reducing vibration certainly wouldn't be a bad idea as I'm sure we have all heard of that bad boy called microphony. However as I already stated they aren't in the cabinet proper so these effects kind of go out the window.

Coil orientation doesn't look to be too bad on those crossovers, while it'd be great if they were all at 90 degrees to each other the sheer number of them looks like it'd make that next to impossible. Maybe some screening might be a better idea.

If we were talking phonostages then I'd be interested in capacitor vibration, but at speaker level, you can smash those caps with a hammer and it won't effect the output. Not unless you have some real junk in there.

[Marco]

Improvements are more likely to come from enhanced layout in the XO, orientation of coils etc than from reduction in drive unit induced vibration which has never proven to exert a measurable effect on the sound.

Just because it's not yet been proven, doesn't mean that the effect doesn't exist! :doh:

I think you're stuggling to grasp that AoS is first and foremost a subjectivist forum, where ears will always be trusted more than measurements, especially when the latter are considered as not 'fit for purpose'.

If you can't embrace and accept that concept, Simon, (as outlined in our ethos), then I'm not sure there is much point in you being here, particularly when others have expressed that your presence, when in 'objectivist mode', is more than a little irritating.

Marco.

P.S You'll be receiving a PM shortly regarding this and your reply to me regarding your unfortunate remarks on pfm about the members of AoS.

[koowat]

I've got the same setup - Hartle's Type 24 and the original crossovers. Why would recapping the originals sound better than the Type 24?

I've bought a pair with the Type 24 and the originals as spares so I am all ears to suggestions.

[Wakefield Turntables]

P.S You'll be receiving a PM shortly regarding this and your reply to me regarding your unfortunate remarks on pfm about the members of AoS.

Can you provide a link... I'd like to read these comments. :cool:

[Reid Malenfant]

If we were talking phonostages then I'd be interested in capacitor vibration, but at speaker level, you can smash those caps with a hammer and it won't effect the output. Not unless you have some real junk in there.
So let me see if I can get where you are coming from... A capacitor in a phono stage that is likely to be in a pretty well sealed case (unless it's a Krell :lol:) which is likely to be a good distance from the speakers & therefore far less likely to be shaken about is more of a worry than one that is having pressure variations due to bass frequencies put about it in a loudspeaker enclosure :scratch:

Ok, so the phono stage is probably seeing a lot less voltage accross the cap, though apart from a cap accross the input the only others I can think of in a decent phono stage are in the feedback & RIAA stages - so at higher voltage.

Now while these phono stage capacitors might have a few hundred millivolts to deal with, I'm sure there is going to a massive difference in vibration/ compression effects etc in a speaker enclosure, like on the order of at least 100 - 1000 times as much. I mean just think about the internal volume of a speaker compared to the average room it'll be placed into :cool:

[worrasf]

Day off today so time aplenty to install the Type 24's - less than an hour for the pair - simples :)

Didn't even bother listening to them for 5 or 6 hours - just put the tuner on and went off to get new suit and stuff for my daughters' wedding next month :eek: :) :rolleyes: :cool: (need an emoticon for "mixed emotions:")

Anyway - first thing to note -Graham did a great job with them - no snap, crackle or pops - quiet as can be.

The type 24's totally change the character of the 149's. They are more dynamic (faster) more revealing of low level detail and more "precise". Presentation is a tad further forward vocals sound more natural (only listened to Bruce Springsteen, Pink Floyd and Thea Gilmore so far). The percussion - esp clocks on Dark Side are awesome. :) BUT - bass is light compared to the previous crossovers. :( What there is is detailed, tuneful and controlled but while the previous ones didn't go low the new ones lack any slam that was present before. "mid bass" like cello's are lovely and natural but double bass and kick drum are just not doing it for me. It's like they are now a "modern" speaker as opposed to a vintage one. Certainly don't have the "warmth" the previous ones had with the Quad's. I'm liking the new realism in the mid-upper frequencies and they certainly get my foot tapping (PRaT) but only time will tell if the bass shyness is a deal breaker. :scratch:

The new foams look the part I think.

Steve

[Reid Malenfant]

Any chance of a picture of the original crossover components? It may well be that the big inductor feeding the bass/mid now has a lower DC resistance, this would lower the Q of the driver in the enclosure & make the bass sound drier, or if you like there would be less of it but it'd be cleaner :)

You could probably swap it out & you should still get the clean mids but with your old bass...

Just a thought :cool:

E2A:- the foam now looks just like the originals - nice!

[worrasf]

From your lips to God's ear

Steve

[YNWaN]

That's funky!

[Reid Malenfant]

Oh crap, they are totally different :doh: While the new one looks like it's 18Db/octave on both legs there are vastly more components on the older version & I can't see the circuit either :(

[worrasf]

Oh crap, they are totally different :doh: While the new one looks like it's 18Db/octave on both legs there are vastly more components on the older version & I can't see the circuit either :(

Circuit diagrams for both x-overs here: http://jr149.wordpress.com/jr149-circuits-diagrams-for-crossovers/

Steve

[Reid Malenfant]

Ah that's better, unfortunately it doesn't help a lot as there are no DC resistance readings of any of the inductors feeding the bass/mid on the original xover, only on the new one which is kind of half handy :D

Do you happen to have a digital multimeter? :scratch:

[worrasf]

Do you happen to have a digital multimeter? :scratch:
I do.
Steve

[Reid Malenfant]

Ok, assuming you can read low resistances fairly accurately or you can set you meter to zero when measuring resistances on the lowest scale, try the following.

Desolder one end of the 22 ohm & 82 ohm resistors in the bass section (only need to desolder one end). Measure the resistance accross L2 & L3 combined in series, make a note of it. Then measure the resistance of L4...

Let me know what they are. I'm assuming that the original xovers are now removed so no drivers are connected :)

That way we can compare the DC resistances of the original inductors & the new ones which you happen to have resistances for ;)

[worrasf]

Thanks for this Mark much appreciated - going to be away for a few days but will take a look when have time.

Graham Hartle confirms that bass will improve with time.

Regards
Steve

[nat8808]

Just because it's not yet been proven, doesn't mean that the effect doesn't exist! :doh:


Just because it hasn't been dis-proven should mean that everyone should be spending their precious, limited life's time and energy on things 'just in-case'..

One has to make a decision on how to best spend their energies.

1) One way of deciding is to listen and make up your own mind (kind of re-inventing the wheel again and again for yourself just to make sure).

2) Another way is to take other people's word for their listening experiences and copying their behaviour, ignoring that they could be mistaken or attributing changes to the wrong thing and also kind of ignoring that they might be experiencing sound completely differently to you.

3) Another way is to look around and only spend time and energy on things that have been repeatedly shown to work or have some merit, not based on hearsay or possibly mis-interpretted experiences.

Depending on what energy and time you have or desire to tinker v listening to music you're probably best working from 3 backwards as your time frees up.

Always people will be subjectively listening to any changes in their system and making up their own minds.

So, I don't think Simon is being non-subjective nor overly objective. He's simply taking an aproach that saves his own time and effort by acting only on what has been shown to work and with resonable explainations attached so as to be sure.

And he wasn't mentioning any measurements. For all you know Marco, these were his or someone else's subjective experiences that had subjectively shown it not to matter based on literally hitting the capacitors with a hammer.

If someone tries something subjectively and finds no difference then surely that is enough proof isn't it? I mean, otherwise you could say that the person just isn't listening right or mistaken or their equipment isn't good enough (I've read all people's arguments over the years) In other words, in a purely subjective world, there is no such thing as proof in any sense!

Oddly, the kind of proof you are saying needs to be shown before disbelieving something is objective proof...

I have read of manufacturers (forum posts perhaps of people who worked there) who moved x-overs out of cabinets and subjectively heard no difference but still left them out so they can appeal to those who see it as the mark of an audiophile company. Can't really remember who it was - might have been B&W with their Silver Signatures as they never did it again.

Then again there are many many DIYers who remove them for sonic reasons, citing vibrational reasons as well as magnetic.

Why not try it and see with these? It's so easy to do with these speakers. Personally it appeals to me but I've no proof as to it being worthwhile..

[Reid Malenfant]

I can think of at least two speakers from totally different manufacturers that have external crossovers (see below). As I pointed out, the ones in the JR149 might as well be as they aren't in the enclosure itself. There are a good few others such as the Kef Reference 105/3 (& no doubt a good few more) that have the same layout as the JRs with it being inside the speaker, but in a seperate cavity.

QLN Signature

ARC 101

[YNWaN]

Yes, I can think of a number of manufacturers who have external x-overs (Naim used to with the SBL and IBL), I can also think of many 'high-end' manufacturers that do not. The main advantage that an external X-over bestows is flexibility (easily removed for going active) - easy to remove/modify; it also means that very much larger components can be used (the higher quality a x-over components gets the bigger it gets - apparently!).

[nat8808]

I've a pair of Celestion SL700s with the x-overs rebuilt with fancy components, set in resin and mounted on the outside in boxes at the back decoupled with rubber mounts. They sound good but I really wish I could compare to the original.

I like the idea but I can't remember reading anyone, DIY or commercial, saying that it definitely made a difference.

Changing the layout of the x-over seems to get enough of a positive response though and obviously mounting them externally allows a lot more freedom and space to arrange optimally so the inductors don't interact with each other electro-magnetically.