Sparky Mark Posted July 17, 2014 Share Posted July 17, 2014 I removed the front grill. I then unscrewed the 3 tweeter screws and lifted the tweeer enough to be able to remove the spade connectors. I then pushed the spade connectors onto the spades on the new tweeter and fed it back into the tweeter mounting hole in the combo. I used 4 matching black pan head screws to secure the HT30. This hole is slightly too small which means the ht doesn't sit perfectly flush but as this is a vented enclosure I am not concerned about having a perfect seal around the tweeter. The 4 fixing screws ensure that the tweeter is held securely. If you are bothered you can open the hole up slightly to allow flush mounting. Seemed like too much bother and mess to me. Quote Link to comment Share on other sites More sharing options...
molan Posted July 17, 2014 Share Posted July 17, 2014 I may well have to do this as well! I've just disabled the stock tweeter completely on my little one at the moment and even that made it sound a lot better to my ears Quote Link to comment Share on other sites More sharing options...
Sparky Mark Posted July 17, 2014 Share Posted July 17, 2014 I disconnected the original one first of all but thought the sound a bit too dull hence buying the HT 30. I found the original harsh and too present. The ht is much more balanced/subtle/refined/not in your face IME. Quote Link to comment Share on other sites More sharing options...
Sparky Mark Posted July 17, 2014 Share Posted July 17, 2014 (edited) Quote "Bill is right though about the tweeter, There is virtually no energy at all above 5kHz where the horn you suggested using starts, so little or no point in adding it unless string noise is something you look for!" The Ht 30 response curve indicates usable output from around 2.5 / 3kHz. So if the MB crossover is at 3.5kHz for all their horns (and the same one is in this combo) then should be okay. It certainly sounds okay to my ears and I also have a CMD121H combo. Edited July 17, 2014 by Sparky Mark Quote Link to comment Share on other sites More sharing options...
Mornats Posted July 20, 2014 Share Posted July 20, 2014 Is this the same tweeter as in the op? http://cpc.farnell.com/_/ht-30/tweeter-8ohm-horn-100w/dp/LS00130 Mcnach, have you taken the plunge yet and fitted yours? I'm about to buy one of these... Quote Link to comment Share on other sites More sharing options...
Lozz196 Posted July 20, 2014 Share Posted July 20, 2014 It`s funny but now I`m using new strings I find even switching off the tweeter in my NY121 ext cab really dulls the sound down, though in my current band I need that cutting-through element to the sound. So really for me, if I ever needed less top-end, I can do it on the ext cab and leave the combo alone. Must admit this wasn`t the case when using dead rounds, so think it might be the same with flats as well. Also question why they have a variable control on the cab but not the combo. Think that`s the only thing missing from the CMD121P. Quote Link to comment Share on other sites More sharing options...
mcnach Posted July 20, 2014 Author Share Posted July 20, 2014 [quote name='Mornats' timestamp='1405851763' post='2505708'] Is this the same tweeter as in the op? http://cpc.farnell.com/_/ht-30/tweeter-8ohm-horn-100w/dp/LS00130 Mcnach, have you taken the plunge yet and fitted yours? I'm about to buy one of these... [/quote] Looks like mine. I haven't had yet the combination of time/will to do it yet, no Quote Link to comment Share on other sites More sharing options...
martthebass Posted July 23, 2014 Share Posted July 23, 2014 Bit of a daft question but how will the sound differ between switching off the tweeter in the 121 and taking it out of circuit? I always use a pair of 121s with the tweeters 'off' and there always seems to be plenty of punch and top end but no harshness. Quote Link to comment Share on other sites More sharing options...
Mornats Posted July 27, 2014 Share Posted July 27, 2014 Just ordered my new tweeter today from here http://www.cybermarket.co.uk/shop/speaker-building/pa-tweeter/img-stageline-ht-30-miniature-852211.html (the other shop didn't have them in stock). I may wait until after our Bristol Balloon Fiesta gig before tampering with the combo though, just in case. Quote Link to comment Share on other sites More sharing options...
Chienmortbb Posted July 28, 2014 Share Posted July 28, 2014 (edited) [quote name='Bill Fitzmaurice' timestamp='1389204252' post='2331349'] It can make the crossover appear as a dead short. Read this: [url="http://www.bcae1.com/xoorder.htm"]http://www.bcae1.com/xoorder.htm[/url] An Lpad will only work as it should with a resistive load, piezos are a capacitive load. To use a piezo with either an LPad or a crossover additional components are required. [/quote] There is much myth and mystery about Piezos and you have to blame Motorola for poor marketing. Piezo tweeters work better and are protected by the series resitor but it does nothing to succesfully integrate a piezo tweeter into a speaker system. For proper balance between the tweeter and the other drivers, it has to have a proper crossover. Then you get a smooth response that will outperform compression drivers. One thing to be aware of though is that if MB only use the dreaded series resistor, then just replacing the piezo with a traditional magnetic tweeter will result in speaker failure eventually and not give a very good performance untill then. Do you have picture of the tweeter? What make and model is it? Edited July 28, 2014 by Chienmortbb Quote Link to comment Share on other sites More sharing options...
mcnach Posted July 28, 2014 Author Share Posted July 28, 2014 I tried to replace the piezo with the HT30 last night. It's a little too large. I could not make it fit. I cut some of the surrounding plastic, similar to the original, but the magnet/terminals just did not fit. I don't want to start messing about with enlarging the original hole... so back I mounted the original and it'll stay that way. Ah well. This is the original one: Quote Link to comment Share on other sites More sharing options...
booboo Posted July 29, 2014 Share Posted July 29, 2014 You are half way there by trimming the plastic on one corner of the tweeter. The hole does need enlarged in a couple of places, but we are only talking about fililng rather than sawing chunks out of the cab and the old tweeter should still fit afterwards if you wish. I did this a while ago, and so far all is good and I have not had any issues, or been arrested by the impedance/crossover police. Quote Link to comment Share on other sites More sharing options...
mcnach Posted July 29, 2014 Author Share Posted July 29, 2014 [quote name='booboo' timestamp='1406620018' post='2512976'] You are half way there by trimming the plastic on one corner of the tweeter. The hole does need enlarged in a couple of places, but we are only talking about fililng rather than sawing chunks out of the cab and the old tweeter should still fit afterwards if you wish. I did this a while ago, and so far all is good and I have not had any issues, or been arrested by the impedance/crossover police. [/quote] I'll probably give it another go at some point... It was one of those 10 minute bouts of extraordinary activity, and it wasn't enough to get to filing anything. You're right, it feels like it just needs a tiny bit of filing. Quote Link to comment Share on other sites More sharing options...
Mornats Posted August 16, 2014 Share Posted August 16, 2014 How do you remove the wires from the spade connectors? Mine just won't budge no matter how much force I put on them. Do I have to peel back the bit on the wire that wraps around the spade bit on the tweeter? Quote Link to comment Share on other sites More sharing options...
Mornats Posted August 16, 2014 Share Posted August 16, 2014 Ah, I did it. I referred to the good old engineering diagram: [attachment=169294:7214525854_733237dd83_z.jpg] Quote Link to comment Share on other sites More sharing options...
Mornats Posted August 16, 2014 Share Posted August 16, 2014 Done! That wasn't bad at all. I'm a complete DIY novice but I managed to get it sorted. I just used a little WD-40 to loosen the spade connectors and they popped out when I used a screwdriver to nudge them a little. Oh, turns out a slug had found its way behind the speaker grill! I found slug trails all over - yuk! So, new tweeter is in. I had to shave (using a cheesegrater!) off a few mm on the top and right hand side so the screw holes would line up. It doesn't sit flush due to a chunk of plastic on the back that holds important looking bits together. If I want to make this a permanent fix I'll go back and shave off some of the wood on the cab so it sits flush. So sound-wise. That annoying hiss is gone! I no longer have to tell people that my combo isn't broken! All of the highs seem there still. I can turn up the treble on my bass and the amp and get no hiss. I'll report back after having been in a live situation but so far I'm happy. I can now mic up my combo to record through Quote Link to comment Share on other sites More sharing options...
LukeFRC Posted August 17, 2014 Share Posted August 17, 2014 [quote name='Bill Fitzmaurice' timestamp='1389222189' post='2331697'] One of the reasons why tweeters and electric bass are not a match made in heaven is that most tweeters don't do much below 4kHz, while added zing is really needed above 2.5kHz. That's with rounds; with flats there's no need for any assistance, even at 2.5kHz. But tweeters capable of going to 2.5kHz, and the crossovers that are necessary to go with them, are more expensive, so they're seldom employed. I wouldn't use tweeters with flats, and when shopping for a cab for rounds I'd be sure that the 2.5kHz range is covered by the tweeter or a midrange driver. [/quote] I must admit I went and looked at the SPL charts you've made for your cabs to see if you did that yourself! as much as i can read SPL charts it looks like it. Quote Link to comment Share on other sites More sharing options...
mcnach Posted August 19, 2014 Author Share Posted August 19, 2014 [quote name='Mornats' timestamp='1408205607' post='2528091'] Done! That wasn't bad at all. I'm a complete DIY novice but I managed to get it sorted. I just used a little WD-40 to loosen the spade connectors and they popped out when I used a screwdriver to nudge them a little. Oh, turns out a slug had found its way behind the speaker grill! I found slug trails all over - yuk! So, new tweeter is in. I had to shave (using a cheesegrater!) off a few mm on the top and right hand side so the screw holes would line up. It doesn't sit flush due to a chunk of plastic on the back that holds important looking bits together. If I want to make this a permanent fix I'll go back and shave off some of the wood on the cab so it sits flush. So sound-wise. That annoying hiss is gone! I no longer have to tell people that my combo isn't broken! All of the highs seem there still. I can turn up the treble on my bass and the amp and get no hiss. I'll report back after having been in a live situation but so far I'm happy. I can now mic up my combo to record through [/quote] Sounds like a result! Let us know how it goes when you use it in anger! Quote Link to comment Share on other sites More sharing options...
Muppet Posted November 14, 2014 Share Posted November 14, 2014 Apologies for dragging this up but better that than starting a new thread... What were the results of any of these modifications any update? I bought a 121P and rather that disconnecting the tweeter I took it and the 'crossover' out of play completely by connecting the speaker lead that comes from the amp output directly to the speaker. Sounds great to my ears and no need to consider a replacement tweeter. And completely reversible. Steve Quote Link to comment Share on other sites More sharing options...
mcnach Posted November 14, 2014 Author Share Posted November 14, 2014 [quote name='Muppet' timestamp='1415990425' post='2605939'] Apologies for dragging this up but better that than starting a new thread... What were the results of any of these modifications any update? I bought a 121P and rather that disconnecting the tweeter I took it and the 'crossover' out of play completely by connecting the speaker lead that comes from the amp output directly to the speaker. Sounds great to my ears and no need to consider a replacement tweeter. And completely reversible. Steve [/quote] Sounds like I might do this myself. I have the HT-30, but after cutting away the excess plastic I realised it does not fit perfectly in the hole, and I didn't feel like starting filing away (won't need much, 'though)... but I should have tried that. Quote Link to comment Share on other sites More sharing options...
Muppet Posted November 14, 2014 Share Posted November 14, 2014 Yeah it's really easy. Unscrew the speaker and you get access to the 'crossover' such as it is. The first set of wires are labelled 'input'. Pull the spades off the connectors and attach them to the speaker and put the wires from the speaker on to the connectors on the crossover. It isolates the tweeter and the crossover and you get the amps full output to the speaker. I was going to swap out the tweeter but really not going to bother now. Steve Quote Link to comment Share on other sites More sharing options...
Sparky Mark Posted December 30, 2014 Share Posted December 30, 2014 Thought I should bring this thread to the top. I have now gigged the HT 30 at full volume with no ill effects. Quote Link to comment Share on other sites More sharing options...
chrisanthony1211 Posted March 14, 2015 Share Posted March 14, 2015 (edited) I have disconnected the tweeter on mine and I'm so pleased to have got rid of that annoying hissing.....are there any other alternative horns that could be fitted other than the HT30????? I don't mind spending a few extra £££ to get the best result! Edited March 14, 2015 by chrisanthony1211 Quote Link to comment Share on other sites More sharing options...
Sparky Mark Posted March 16, 2015 Share Posted March 16, 2015 [quote name='chrisanthony1211' timestamp='1426359615' post='2717355'] I have disconnected the tweeter on mine and I'm so pleased to have got rid of that annoying hissing.....are there any other alternative horns that could be fitted other than the HT30????? I don't mind spending a few extra £££ to get the best result! [/quote] It's not so much about the money but the available space for a replacement tweeter. The HT30 is a good alternative that will fit without any mod to either the combo or HT30. For the low cost it's worth trying one to see what you think. I found the piezo really spitty and annoying and the HT30 sounds good IMO. YMMV. Quote Link to comment Share on other sites More sharing options...
chrisanthony1211 Posted March 17, 2015 Share Posted March 17, 2015 Thanks for the advice, I've just ordered one from ebay for £10.......can't go wrong for that price if it improves the sound.. Quote Link to comment Share on other sites More sharing options...
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