Abbot's Tweets Job

[Fatmarley]

If you get the polarity wrong on the tweeter, you could end up with this.

 

[The Abbot]

@Fatmarley yes thanks, so I was mostly on the right track then. The port line although I didn know what it was, I dud guess as n/a (& there's one other line on it: I have to assume must also be n/a).

Yes I did see the dip thing in blue, & understood this is not what I want, & understand this is what the wrong polarity will do. I understand the dotted red line is what I want.

As to whether I can determine this though via listening though.. as I don't have the facility to put the tone thing via a computer > through my amp.

 

[Fatmarley]

The original Epos tweeter wasn't reversed, so it's likely that you won't need to reverse it. I'm just trying to cover all possible outcomes.

 

[The Abbot]

The original Epos tweeter wasn't reversed, so it's likely that you won't need to reverse it. I'm just trying to cover all possible outcomes.

Thanks indeed FatM. I should have a 1st try today or tmrw: waiting on resistors at the mo.

I think the wrong polarity might mean the voicecoil working inwards, rather than outwards, in its recess. If so surely this would be audibly incorrect.

Cheers, Abbot

 

[Fatmarley]

Thanks indeed FatM. I should have a 1st try today or tmrw: waiting on resistors at the mo.

I think the wrong polarity might mean the voicecoil working inwards, rather than outwards, in its recess. If so surely this would be audibly incorrect.

Cheers, Abbot

Exciting! Just don't be too disheartened if they sound bad. It will be purely down to the crossover, and should be fixable.

Reverse polarity is sometimes the correct polarity.

 

[The Abbot]

Exciting! Just don't be too disheartened if they sound bad. It will be purely down to the crossover, and should be fixable.

Reverse polarity is sometimes the correct polarity.

Got resistors, but forgot i ran out of solder.. urgh, this wait is a ballache! apologies.

In meantime, my 7 watters measure 7.2r & 7.3r.. 5% tolerance so I think this is ok? 3.3uf caps I have.

Trying to glean what more I can from the chart above; is this the stereophile chart.. or is it my woofer's curve, plus the morel tweeter curve ontop? Or can these two curves only actually be measured, once I get them in with these cap+r's in place?

Thanks, Abbot

 

[The Abbot]

Anyone.. ( not sure if anyone bar FatM is awake tho!)

Is a 250v film cap ok for speakers?

I've only seen 400v or so on caps indide a hifi spkr.. I've sometimes wondered why so high if I measure ~35mV (I think mV is correct) across my naim 140 spkr terminals. Assuming a 'normal' amp > spkr figure.

 

[Fatmarley]

Got resistors, but forgot i ran out of solder.. urgh, this wait is a ballache! apologies.

In meantime, my 7 watters measure 7.2r & 7.3r.. 5% tolerance so I think this is ok? 3.3uf caps I have.

Trying to glean what more I can from the chart above; is this the stereophile chart.. or is it my woofer's curve, plus the morel tweeter curve ontop? Or can these two curves only actually be measured, once I get them in with these cap+r's in place?

Thanks, Abbot

You won't hear the difference between 7.2 and 7.3R resistors, and 3.3uf caps are fine. 250v caps are also fine. A lot of speakers have 50v caps in, but that's about the lowest you'll find.

The chart above is just the Stereophile measurements, showing a possible scenario (dip in frequency response with the wrong polarity). The only way to know exactly what's happening with your Morel tweeter, would be to measure, and the only way to model a crossover properly is to measure the drivers in the enclosure, without any components connected.

 

[The Abbot]

You won't hear the difference between 7.2 and 7.3R resistors, and 3.3uf caps are fine. 250v caps are also fine. A lot of speakers have 50v caps in, but that's about the lowest you'll find.

The chart above is just the Stereophile measurements, showing a possible scenario (dip in frequency response with the wrong polarity). The only way to know exactly what's happening with your Morel tweeter, would be to measure, and the only way to model a crossover properly is to measure the drivers in the enclosure, without any components connected.

That's good then: so I've got 5.6r 7w on their way, & 2.2/250 film caps (& some 6.8r's & 3.3uf too).

So a few to do innitial 'tests' here.

Ah so, if I were to bring over (I'm actually in broadway in a month 6/09 to see my oldies for a few days.. but may not be suitable for you) you'd want with cap & resistors removed 1st ( kept with them: i mustn't forget!).

Thanks, Abbot

 

[Fatmarley]

That's good then: so I've got 5.6r 7w on their way, & 2.2/250 film caps (& some 6.8r's & 3.3uf too).

So a few to do innitial 'tests' here.

Ah so, if I were to bring over (I'm actually in broadway in a month 6/09 to see my oldies for a few days.. but may not be suitable for you) you'd want with cap & resistors removed 1st ( kept with them: i mustn't forget!).

Thanks, Abbot

Yes, best to remove them before bringing them over.

I would/will just use the binding posts on the back of the speaker for testing components.

 

[The Abbot]

Yes, best to remove them before bringing them over.

I would/will just use the binding posts on the back of the speaker for testing components.

Hi FatM. Got tweeters etc in. Had first listen..

Good innitial results. There doesn't seem anything obviously out of kilter, so the polarity thing is ok I think.

Can't hear any obvious volume/ db imbalance either. So a damn good choice of xy&z new things, it seems if such results at this stage.

As to tweeter performance: I can hear more things going on & more texture, even not with amp more than 10 o'clock volume knob ( tentative start). Perhaps a little more bloomy lower mids, it seems.. could I be correct?

I'll have a better appraisal here later this ev. I think... maybe... I've got a potential cracker though. I mean if the crossover could be tweaked, to seal the deal as it were, these are surely full of huge potential now.

I think too, altho my knowledge poor, my instinct that the es14 tweeter is the weak point, & a better tweeter + this existing mid/ bass unit might be a winner idea.. might seem justified/ vindicated.

Thanks so much FatM, you've given me much of your time & ideas.. really grateful to you.

Abbot.

 

[Fatmarley]

That's good to hear. If the tweeter is a bit low in level, that could cause the lower mids to sound a bit bloomy. You could try a lower value resistor to bring up the treble level, to see if that helps.

I agree that it does look like the tweeter is the weak link. It looks pretty bad on paper at least, and I'm not a big fan of metal tweeters anyway.

Give them a good blast and see what you think. You should never evaluate speakers at low volume. IIRC my old loudspeaker design book recommended around 90db.

 

[The Abbot]

That's good to hear. If the tweeter is a bit low in level, that could cause the lower mids to sound a bit bloomy. You could try a lower value resistor to bring up the treble level, to see if that helps.

I agree that it does look like the tweeter is the weak link. It looks pretty bad on paper at least, and I'm not a big fan of metal tweeters anyway.

Give them a good blast and see what you think. You should never evaluate speakers at low volume. IIRC my old loudspeaker design book recommended around 90db.

Good then I'll pop in the 5.6r's next I think. No I need a bit of vol/ welly to get past my ear hair spriggots.

Abbot

 

[The Abbot]

Good then I'll pop in the 5.6r's next I think. No I need a bit of vol/ welly to get past my ear hair spriggots.

Abbot

@Fatmarley More judgement after some fair welly, thus;

I think maybe the tweeter is both a tad bright/ thin, as well as the tad of bloominess to midbass. Only a tad really, as far as my clothears can establish.

Would How about a bit less r @ 5.6r & a bit less cap @ 2.2uf? Am I barking up the right tree?

Thanks, Abbot

 

[Fatmarley]

@Fatmarley More judgement after some fair welly, thus;

I think maybe the tweeter is both a tad bright/ thin, as well as the tad of bloominess to midbass. Only a tad really, as far as my clothears can establish.

Would How about a bit less r @ 5.6r & a bit less cap @ 2.2uf? Am I barking up the right tree?

Thanks, Abbot

This is where it really helps to have measurements.

I honestly haven't a clue what to suggest. It may be best to write down what you've tried with a description of the sound, and just keep trying different combinations. This is the reason why the crossover is best on the outside, it just makes if far easier to experiment.

 

[Lawrence001]

Word of advice, tuning a crossover by ear is hard work as you need to know what you're doing (ie. have experience, although trying to work it out from trial and error is an interesting exercise) and once you've got it relatively close, which it sounds like you have, you have to spend longer listening to each tweak to understand how it sounds.

As @Fatmarley says having an exterior crossover, at least temporarily until you have finished tuning, is a good idea. As well as convenience, I'm not sure how the screws in the ES14s are but if they are direct into the wood (unlikely with such well made speakers) eventually it will wear out the holes.

Am I right in thinking the bass speaker is run full range so you are replacing the original cap with a cap plus resistor to pad down the tweeter? I'd start with the same cap as before plus an L-pad to get the right level, which can then be fixed once you've finished.

 

[The Abbot]

This is where it really helps to have measurements.

I honestly haven't a clue what to suggest. It may be best to write down what you've tried with a description of the sound, and just keep trying different combinations. This is the reason why the crossover is best on the outside, it just makes if far easier to experiment.

Understood. My spkr cable plugs such a pain to refettle at the back to do this tho, its almost as easy to redo on back of the tweeter. Thank goodness only 2 components!

Thanks, Abbot

 

[The Abbot]

Word of advice, tuning a crossover by ear is hard work as you need to know what you're doing (ie. have experience, although trying to work it out from trial and error is an interesting exercise) and once you've got it relatively close, which it sounds like you have, you have to spend longer listening to each tweak to understand how it sounds.

As @Fatmarley says having an exterior crossover, at least temporarily until you have finished tuning, is a good idea. As well as convenience, I'm not sure how the screws in the ES14s are but if they are direct into the wood (unlikely with such well made speakers) eventually it will wear out the holes.

Am I right in thinking the bass speaker is run full range so you are replacing the original cap with a cap plus resistor to pad down the tweeter? I'd start with the same cap as before plus an L-pad to get the right level, which can then be fixed once you've finished.

Hi Lawrence. This is valuable information & seems sensible. You can easily fool yourself too hearing what you want, not what's avtually there I'd say too.

Yes Im actually simply using the original cap at the mo, 3.3uf. And just added a 6.8r to I believe pad the tweeter down. Simple as that.

External x'over in principle fine.. but with my diy links between the terminals, on the back of the speaker, quite a faff to make.. splitting somehow & introducing a junction to insert a component or two... is a huge pickle to work out how. Easier, as only 2 components, to take tweeter out tbh.

Thanks, Abbot

 

[The Abbot]

This is where it really helps to have measurements.

I honestly haven't a clue what to suggest. It may be best to write down what you've tried with a description of the sound, and just keep trying different combinations. This is the reason why the crossover is best on the outside, it just makes if far easier to experiment.

Morning FatM. But you did mention early on to 'try a lower vale cap if a bit too bright'.. which is simply what I thought to do. I might try just this first. Then adjust the tweeter level with the resistor.

I mean as best I can attempt, using my hairy ears to judge. I think further tinkering here, won't be of too much use: & at this point ideally got to yours.

I'll report back on the 2.2uf cap change ( from original 3.3uf cap Im using at the mo).

Thanks, Abbot

 

[Lawrence001]

If it was me, before changing the cap I'd have a play with an L pad have a look at this

http://www.sengpielaudio.com/calculator-Lpad.htm