How to reduce tweeter level after crossover?

romanber · « **on:** 25 Jul 2005, 02:46 pm »

How can I reduce tweeter levels in a two-way car speaker with external crossover (that does not have level adjustment)? Can I plug something between the crossover and a tweeter to lower signal level? I don't know much about electronic design... Putting a resistor comes to mind, but it sounds to simple to work, is it? Those speakers are fed from two channels of 4x70W amp.

Here is the story:

I have replaced the factory system in my Chrysler Intrepid with Infinity Kappa speakers on the front and 3-way Pioneers on the rear. There is too much harsh high frequencies on Kappas. Pioneers were much more balanced (more lika any other speaker I know). It seems that tweeter level of the Kappas is just set too high, but there is no tweeter level adjustment control on the included external crossovers (small sealed black boxes)

I'm puzzled on whyInfinity Kappas being such a good car speakers have as uneven response as I'm hearing...

Maybe someone here would know how to solve this, if there is an easy solution. Thanks!

PEB · « **Reply #1 on:** 25 Jul 2005, 03:02 pm »

This is a passive crossover between amp and tweeter, right? Not active between head unit and amp?

If so, you could send me the DC resistance of the tweeter, and the amount in dB that you want to reduce it by.

I could then calculate an L-pad (2 resistors) for you. I suppose you could also try a variable L-pad from Radio Shack...

romanber · « **Reply #2 on:** 25 Jul 2005, 03:16 pm »

Quote from: PEB

This is a passive crossover between amp and tweeter, right? Not active between head unit and amp?

If so, you could send me the DC resistance of the tweeter, and the amount in dB that you want to reduce it by.

I could then calculate an L-pad (2 resistors) for you. I suppose you could also try a variable L-pad from Radio Shack...

Thanks! Yes, it is a passive crossover. It has 2 wires that connect to an amp and 4 that connect to woofer and tweeter terminals on this coaxial speaker.

L-Pad sounds like what I need. As it's hard to know in advance desired db reduction, is it possible to make a variable pad by using a variable resistor? or shold those two resistors vary accordingly?

I can't find that "variable L-Pad" part on Radioshack website. Could you point me to it? Is it difficult to assemble it myself if I can't find it here in Totonto?

Oh, and the speakers are supposed to be 4-Ohm. Would tweeter have different rating? I guess I could take it out and measure it witha multimeter...

PEB · « **Reply #3 on:** 25 Jul 2005, 03:52 pm »

I didn't see it with a search of their site.

Why don't you just call the nearest one and ask?

romanber · « **Reply #4 on:** 25 Jul 2005, 03:58 pm »

I will do that. Although RadioShacks in Toronto seem to carry much less stuff than in US.

Generally, what kind of L-Pad should I look for? I have found some info on the net, seems there are several types, like 50W 16 Ohm, 25W 16 Ohm, 50W 8 Ohm and even 100W 8 Ohm etc.

I think if the total speaker impedance is 4 Ohm, tweeter alone would be something like 8 Ohm, right? What wattage would be right? Something like this: http://mcm.newark.com/NewarkWebCommerce/mcm/en_US/endecaSearch/partDetail.jsp?SKU=50-475&N=0

PEB · « **Reply #5 on:** 25 Jul 2005, 04:02 pm »

Put a DVM on the leads going into the tweeter. Then you can determine what the nominal impedance of it is.

Let me know what you find, and then I'll make a recommendation.

romanber · « **Reply #6 on:** 25 Jul 2005, 04:10 pm »

Quote from: PEB

Put a DVM on the leads going into the tweeter. Then you can determine what the nominal impedance of it is.

Let me know what you find, and then I'll make a recommendation.

Sorry for a stupid question, I'm not good at electronic lingvo

DVM? Is it a multimeter? I have a decemt multimeter that measures impedances, is that what you mean - apply it to - and + terminals of the tweeter (under no load with amp off) and read the impedance in Ohms? Just to clarify...

PEB · « **Reply #7 on:** 25 Jul 2005, 04:12 pm »

That's right.

romanber · « **Reply #8 on:** 25 Jul 2005, 04:16 pm »

Thanks a lot for your help! I will measure the tweeter impedance within a couple of days (some door disassembling required) and post what I find.

markC · « **Reply #9 on:** 25 Jul 2005, 10:16 pm »

Q components is a mail order company and I believe they have what you are looking for. They are located in Waterloo, On. 50 watt mono unit, (you will need 1 per tweet), part # LP50 or stereo 50 watt unit, part # LP50S. Their help line # 1-519-884-1140, order line # 1-800-363-6336. I used the monos on a pair of giant speaks I built a few years back to pad down the mid drivers. They range from odb to -16db. Should be just what you're looking for. Oh ya, and they're cheap, around CA$12 each for the monos.

romanber · « **Reply #10 on:** 26 Jul 2005, 12:18 am »

Quote from: markC

Q components is a mail order company and I believe they have what you are looking for. They are located in Waterloo, On. 50 watt mono unit, (you will need 1 per tweet), part # LP50 or stereo 50 watt unit, part # LP50S. Their help line # 1-519-884-1140, order line # 1-800-363-6336. I used the monos on a pair of giant speaks I built a few years back to pad down the mid drivers. They range from odb to -16db. Should be just what you're looking for. Oh ya, and they're cheap, around CA$12 each for the monos.

Thanks! Very good to know such company!

I emailed the Infinity techsupport and they suggested rotating tweeters away (they rotate to aim for the listener and were aimed upwards), that should give 3-4dB reduction on tweeters. I did that and results are acceptable (Maybe I'd like another 1-2 dB, but it's OK, and I could adjust the sound not to suck at the rear). I will think about putting additional pad, maybe it's not needed after all. I'll give it a few days of listening...

PEB · « **Reply #11 on:** 26 Jul 2005, 01:39 am »

A general rule of thumb that I use is to judge the tweeter level after one hour. It is OK only if you are not fatigued at that point.

Be careful of long term levels in a car!

romanber · « **Reply #12 on:** 26 Jul 2005, 02:19 am »

Quote from: PEB

A general rule of thumb that I use is to judge the tweeter level after one hour. It is OK only if you are not fatigued at that point.

Be careful of long term levels in a car!

Thanks, I'll keep that in mind. That's why I was telling about few days. I'll see if it irritates me or not by that time. BTW I don't listen at very high levels but I like to enjoy a good quality sound. For example, I need a subwoofer to fill the low end that was lacking but not to create window-shattering thump...