Greetings once again! I registered several years ago but now all of a sudden my login would not work, so I had to re-register! Kind of a hassle, but no big deal. It's worth it.
I've been installing car audio in all my cars as well as for friends and family since the mid 70's. In 1995, I missed 2 questions in the MECP master installer test, so never got certified but to this day I consider the MECP study guide my bible! I use it for a wealth of information!
Now for my mistake! I've used tweeters in many car audio systems over the years. Started with Kenwood, but eventually Pioneer upgraded their tweeters and I've stuck with Pioneer for years. But recently I purchased a pair of Alpine DDT-S30 tweeters on eBay for about $20. I chose Alpine because they had a pretty decent frequency response, which is what I always look for first when considering speakers.
To begin with, when I opened the box of the "brand new" tweeters and connected them, there was NO SOUND! I then removed the crossovers and reconnected the tweeters and they worked! That showed me the crossovers did NOT work! Yeah, yet another time I got ripped off on eBay! But thankfully I had a few sets of bass blockers in my hardware bins from previous tweeter installations, so I used my black PAC BB6-PR bass blockers from my previous cars, rated at 5,600 Hz. The Alpines worked with these!
In ALL my tweeter installations, I've wired them off the head unit and used the amps for the other speakers. This time, I wanted to try running the tweeters off my amp because I can equalize them using my 7-band equalizer. I hooked them in parallel with the front door speakers which are Pioneer 4-way 6.5's. They sounded totally awesome... for ONE DAY! Yep, apparently, even with bass blockers, these tweeters could not handle the power of the amp (it's only 75 wpc RMS at 4 ohms, 110 wpc RMS at 2 ohms, not sky-high mega-watts). Yesterday, when de reggae was jammin, mon, all of a sudden out of the blue, the tweeters quit! I was NOT happy! About as happy as when I got them and discovered both crossovers were junk!
So the reason for my post is I was wondering how many others here have wired their tweeters in parallel with their front stage speakers off an amp, and if there were any problems. Also, I figured what had happened was that I fried the bass blockers because they only handle 50 wpc max while I was running 75 wpc continuous off my Nakamichi NGXA-80.4 amp, a 4-channel amp. I removed the bass blockers and checked them with a continuity tester. Nothing! So I checked a couple other pairs of bass blockers for continuity and got a light, although very dim.
I assumed (yes, I know what happens when you assume!) that too much power frying the bass blockers would simply break the line of power to the speaker, almost like a blown fuse, and not let anything go past them to the tweeters. Now, I'm thinking more like if you burn out a bass blocker, they don't act like a fuse, but instead just let ALL frequencies go through them. Is this correct?
Is there a way to test a bass blocker with a digital multimeter? I have one that measures just about everything you could imagine, including RMS! I'm not sure if I should check for resistance or what.
I put in a different set of bass blockers and still no sound, so I'm guessing my tweeters are dead.
Sorry for the mini-novel here, but I wanted to be clear on what I was trying to do, what I hoped would work, what didn't work, and the fatal results of wiring tweeters in parallel with front speakers off an amp. The next tweeters WILL be connected right the the head unit instead of an amp!
I've been installing car audio in all my cars as well as for friends and family since the mid 70's. In 1995, I missed 2 questions in the MECP master installer test, so never got certified but to this day I consider the MECP study guide my bible! I use it for a wealth of information!
Now for my mistake! I've used tweeters in many car audio systems over the years. Started with Kenwood, but eventually Pioneer upgraded their tweeters and I've stuck with Pioneer for years. But recently I purchased a pair of Alpine DDT-S30 tweeters on eBay for about $20. I chose Alpine because they had a pretty decent frequency response, which is what I always look for first when considering speakers.
To begin with, when I opened the box of the "brand new" tweeters and connected them, there was NO SOUND! I then removed the crossovers and reconnected the tweeters and they worked! That showed me the crossovers did NOT work! Yeah, yet another time I got ripped off on eBay! But thankfully I had a few sets of bass blockers in my hardware bins from previous tweeter installations, so I used my black PAC BB6-PR bass blockers from my previous cars, rated at 5,600 Hz. The Alpines worked with these!
In ALL my tweeter installations, I've wired them off the head unit and used the amps for the other speakers. This time, I wanted to try running the tweeters off my amp because I can equalize them using my 7-band equalizer. I hooked them in parallel with the front door speakers which are Pioneer 4-way 6.5's. They sounded totally awesome... for ONE DAY! Yep, apparently, even with bass blockers, these tweeters could not handle the power of the amp (it's only 75 wpc RMS at 4 ohms, 110 wpc RMS at 2 ohms, not sky-high mega-watts). Yesterday, when de reggae was jammin, mon, all of a sudden out of the blue, the tweeters quit! I was NOT happy! About as happy as when I got them and discovered both crossovers were junk!
So the reason for my post is I was wondering how many others here have wired their tweeters in parallel with their front stage speakers off an amp, and if there were any problems. Also, I figured what had happened was that I fried the bass blockers because they only handle 50 wpc max while I was running 75 wpc continuous off my Nakamichi NGXA-80.4 amp, a 4-channel amp. I removed the bass blockers and checked them with a continuity tester. Nothing! So I checked a couple other pairs of bass blockers for continuity and got a light, although very dim.
I assumed (yes, I know what happens when you assume!) that too much power frying the bass blockers would simply break the line of power to the speaker, almost like a blown fuse, and not let anything go past them to the tweeters. Now, I'm thinking more like if you burn out a bass blocker, they don't act like a fuse, but instead just let ALL frequencies go through them. Is this correct?
Is there a way to test a bass blocker with a digital multimeter? I have one that measures just about everything you could imagine, including RMS! I'm not sure if I should check for resistance or what.
I put in a different set of bass blockers and still no sound, so I'm guessing my tweeters are dead.
Sorry for the mini-novel here, but I wanted to be clear on what I was trying to do, what I hoped would work, what didn't work, and the fatal results of wiring tweeters in parallel with front speakers off an amp. The next tweeters WILL be connected right the the head unit instead of an amp!
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A bass-blocker is typically nothing more than a capacitor with a high value resistor in parallel with it. It's VERY difficult to damage them.
If the tweeters have a magnet, you can check the resistance of the voice coil to determine if they're blown.
If you have any other mid/high range speaker, you can connect the bass-blocker in series with that speaker to see if they pass audio.
5.6kHz may have been too low for the tweeters.
Wiring the tweeters parallel had nothing to do with the failure.
If the tweeters have a magnet, you can check the resistance of the voice coil to determine if they're blown.
If you have any other mid/high range speaker, you can connect the bass-blocker in series with that speaker to see if they pass audio.
5.6kHz may have been too low for the tweeters.
Wiring the tweeters parallel had nothing to do with the failure.
Thanks for the info!
I haven't tested the tweeters without a bass blocker, but will today. I'll remove ones I put in yesterday when they quit and see if I have sound from the tweeters without them. I'm already thinking about getting a newer, better pair of tweeters to replace these Alpines. I never imagined I'd have to use bass blockers when the tweeters came with crossovers! UGH!
I can try your suggestion off my front door speakers. They're Pioneer TS-A1686R 4-way full-ranges. They got the best frequency response I could find in a 6.5 in my price range, as do the rear Pioneer TS-A6990F 6x9 5-ways. I just needed more crystal clear highs, which I got from these tweeters... for one day! I'm wondering in Alpine tweeters are just junk. Never had issues with Kenwood or Pioneer tweeters, but then I've never connected tweeters to an amp.
Thanks again! I'll do some more testing! I'm hoping like heck the tweeters ARE still okay!
I haven't tested the tweeters without a bass blocker, but will today. I'll remove ones I put in yesterday when they quit and see if I have sound from the tweeters without them. I'm already thinking about getting a newer, better pair of tweeters to replace these Alpines. I never imagined I'd have to use bass blockers when the tweeters came with crossovers! UGH!
I can try your suggestion off my front door speakers. They're Pioneer TS-A1686R 4-way full-ranges. They got the best frequency response I could find in a 6.5 in my price range, as do the rear Pioneer TS-A6990F 6x9 5-ways. I just needed more crystal clear highs, which I got from these tweeters... for one day! I'm wondering in Alpine tweeters are just junk. Never had issues with Kenwood or Pioneer tweeters, but then I've never connected tweeters to an amp.
Thanks again! I'll do some more testing! I'm hoping like heck the tweeters ARE still okay!
Alpine isn't known for being junk but you weren't using them with the crossovers that they were designed to be used with.
Bass-blockers are only 6dB/octave so you have to cross relatively high to keep the low frequencies out of the tweeters. Bass-blockers aren't typically made to be used for tweeters.
Crystal clear highs may mean high output level. MANY tweeters will produce crystal clear audio well beyond what you can hear (frequency) but may not be what you are looking for if they're not efficient enough.
You can't go by the power ratings. They mean very little, especially for tweeters. These are rated for 50w RMS but it's likely that if you drove a 10kHz sine wave of 50W into the tweeters that they wouldn't last more than a few seconds. If you need high level output from tweeters, you need to cross them over as high as possible with a crossover with at least 12dB of slope.
Bass-blockers are only 6dB/octave so you have to cross relatively high to keep the low frequencies out of the tweeters. Bass-blockers aren't typically made to be used for tweeters.
Crystal clear highs may mean high output level. MANY tweeters will produce crystal clear audio well beyond what you can hear (frequency) but may not be what you are looking for if they're not efficient enough.
You can't go by the power ratings. They mean very little, especially for tweeters. These are rated for 50w RMS but it's likely that if you drove a 10kHz sine wave of 50W into the tweeters that they wouldn't last more than a few seconds. If you need high level output from tweeters, you need to cross them over as high as possible with a crossover with at least 12dB of slope.
The tweeters need a crossover/filter of some sort for protection. I wouldn't wire them directly to the amp, even for testing.
Or you can actively cross them with an HPF filter from the head unit/dsp/or the amplifier itself at 6.3khz or 8khz with at least of 12dB slope but in this case you will need separate channels for the highs.
Even with active filtering, it's good to have a capacitor in series with the capacitor to protect from DC voltage from the amplifier (in case of failure or some other problem).
Hairball, your browser seems to have double spaced between lines (I've adjusted them). If you are using firefox, there is a fix for this..
Open a tab and type: about:config into the address bar
Then find editor.use_div_for_default_newlines
and change true to false.
Open a tab and type: about:config into the address bar
Then find editor.use_div_for_default_newlines
and change true to false.
Perry is correct in that there should always be some “protection” for a tweeter, since they can have very low power handling, and an amp turn-on can easily have a healthy dc surge. Even the guys running active do this.
A site for quick capacitor filter (high/low pass/bass blocker/crossover) values is this one.
ERSE - Crossover Calculator - First Order 2 Way
Welcome to diyaudio, used to live in T-town myself...
A site for quick capacitor filter (high/low pass/bass blocker/crossover) values is this one.
ERSE - Crossover Calculator - First Order 2 Way
Welcome to diyaudio, used to live in T-town myself...
in using a full range mid in parallel with a tweeter that has a capacitor in series, wouldnt that channel's impedance be "unstable" at frequencies above the bass blocker?
Are you under the impression that the impedance of a 4 ohm speaker load is 4 ohms across the spectrum?
A well designed amplifier can drive any load above the minimum rated impedance without a problem, no matter how complex the actual impedance curve is.
A well designed amplifier can drive any load above the minimum rated impedance without a problem, no matter how complex the actual impedance curve is.
No, i am not under that impression as i do understand the "nominal impedance" of a speaker. I understand the amp will perform fine. My question is in regards to how the capacitor plays its role. In you typical component set, the crossover most of the time sends the lower frequencies to your mid/woofer while the tweeter receives the highs, resulting in your amplifier seeing a perceived "1" speaker due to the crossover. Lets say your amp is rated at 50x4@4 and 100x4@2. If you do not have the mid filtered and the tweeter has a bass blocker, if you send out a test tone lower than the bass blocker it would be in the @4 category yet if you sent out a higher tone it would be in the @2 rating?
The amp produces a voltage and the current that flows will be determined by the impedance of the load at any given frequency. The amp doesn't care what the load is as long as it's above the lowest rated load.
Right, so that’s a description of ohms law. But, I am asking about the frequencies and their relation to a single speaker with a capacitor instead of a traditional crossover setup where both are crossed over.
At these tweeter frequencies, the impedance of the mid driver will be on the rise, as they tend to do. Once it is significantly higher than the tweeter's 4 ohms it has no significant effect on the combination. Using an inductor to filter the mid driver would increase this tendency, but it isn't strictly dependent on it. For a better answer than that, each separate case would have to be measured.
The main end-user concern is usually with phasing of separately crossed over drivers with respect to frequency separation and clarity. A frequency dependent interference pattern that causes "beat note" hills and valleys in the frequency response when drivers are helping/fighting each other in the overlap zone. It's not impossible to overload an amp with high frequency drivers, but the mids aren't usually a concern in that respect. As previous members have pointed out, the mids rise in impedance quickly with high frequency unless they are specifically designed not to. However, blowing out tweeters usually happens not from raw power, but harmonic distortion being thrown into them. That's a sure fire way to fry most any tweeter: overdrive a capable amplifier with high frequency fizz.
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