Tweeter and crossover confusion

[Codym42]

Hey guys,

I'm going to be redoing the stereo in my e30 soon and I have a few questions, mainly about tweeters and crossovers.

Current setup:
Pioneer Deh-p5200hd headunit
5.25 2 way Kenwood kick panel speakers
e30 stock sail panel tweeters (not sure how they are wired)
Cerwin Vega 5.25 2 way Rear speakers

I bought some alpine add on tweeters to replace the stock BMW ones. (http://www.sonicelectronix.com/item_...SPS-110TW.html) They come with in-line crossovers and I was going to wire them up to the kick panel speakers (wired parallel, I believe). I've been reading that this creates a 2 ohm load on the amp and also, that the power is not very well distributed for the highs because the crossovers aren't really connected to the 2 ways I already have (They're connected but only filtering frequencies for the tweeters).

Just wanted to see what the r3v stereo experts think about this. Is it really that much of an issue or should I sell the tweeters and get some real component speakers?

The entire system will soon be powered by a Planet Audio ac1800.5 5 channel amp. I should add that it can support a 2 ohm load. Also will be adding a sub, box, etc.

[pgaustin]

In the stock setup the crossover for the tweeter is integrated into the midbass driver in the kick panel. It's a coil wrapped above the magnet and side mounted capacitor. When the 2-way speakers were installed either the original tweeters were disconnected or some other crossover was engineered. Otherwise it's likely they were cooked if they were driven off the raw signal.

The highs from the Kenwoods probably aren't very strong mounted in the kicks, however, adding the Alpine tweeters along with the Kenwood 2-ways is likely to produce way too much high end. I would consider replacing the Kenwoods with a good mid-bass driver. I'm using the *highly acclaimed* E34 mid-bass drivers along with some Dayton tweeters and a custom crossover/attenuation circuit and it sounds pretty good.

Before doing anything else, I would take some measurements with an RTA (real-time analyzer) and identify where your problems are. If you have an iPhone or iPad get AudioTools ($10) and do RTA tests with pink noise. If you want the most accurate measurements get the $17 tuned mic recommended by the app developer although you can get by without it. The following link has a good explanation of the frequency response you are looking for: http://www.carstereochick.com/2012/0...-audio-system/. I'd also use the app to check whether you have any phase issues before you run the RTA. When you get your final hardware configuration installed you will also find the app invaluable in getting everything tuned.

If you end up keeping the Alpine tweeters, you will likely need to match there output level to whatever you end up with in the kick-panel. This is a strong argument for going with a component set where this has already been done for you. If the provided crossover has a level adjustment it will be much easier and you can look at the upper frequency response in the RTA plot to tell when it's right. If you don't have a level adjustment, you will need to figure out how much attenuation you need and build an l-pad circuit to get it right.

Your going to have a hard time getting decent low end out of 5.25" speakers. Low-cost (and some high cost) 5.25" 2-way coax and component sets tend to have low response below 100Hz (or even higher). This is a big part of the argument for the e34 drivers as they have *decent* (but not spectacular) low end. The e34 low end is probably better than your Kenwoods or Cerwin Vegas. This may however not be true for the rest of the speaker range. So if you want good sound be prepared to add a subwoofer. In the e30 coupe this is pretty easy (I have a convertible which is not). A small sealed box shooting through the ski-pass with an 8" or 10" sub will add what you need. If your not up to building the box get this one: http://www.germanaudiospecialties.co...enclosure.html or the 10" or 12" version.

You will also improve sound dramatically by adding an AMP. I'm using a Precision Power Black ice 4 channel/1600 watt for the main speakers and a 1300 watt monoblock from the same line for the sub. I've found these to be decent quality and can be had for about $80 each.

That should give you plenty to think about. Depending on the quality of sound you want there's a lot more to consider such as sound dampening (dynomat), active vs passive crossovers (I wish now that I'd gone with active), sound processing/equalizations (to compensate for the zany way sound bounces around and resonates in the cabin), etc.

Good Luck....

[Codym42]

In the stock setup the crossover for the tweeter is integrated into the midbass driver in the kick panel. It's a coil wrapped above the magnet and side mounted capacitor. When the 2-way speakers were installed either the original tweeters were disconnected or some other crossover was engineered. Otherwise it's likely they were cooked if they were driven off the raw signal.

The highs from the Kenwoods probably aren't very strong mounted in the kicks, however, adding the Alpine tweeters along with the Kenwood 2-ways is likely to produce way too much high end. I would consider replacing the Kenwoods with a good mid-bass driver. I'm using the *highly acclaimed* E34 mid-bass drivers along with some Dayton tweeters and a custom crossover/attenuation circuit and it sounds pretty good.

Before doing anything else, I would take some measurements with an RTA (real-time analyzer) and identify where your problems are. If you have an iPhone or iPad get AudioTools ($10) and do RTA tests with pink noise. If you want the most accurate measurements get the $17 tuned mic recommended by the app developer although you can get by without it. The following link has a good explanation of the frequency response you are looking for: http://www.carstereochick.com/2012/0...-audio-system/. I'd also use the app to check whether you have any phase issues before you run the RTA. When you get your final hardware configuration installed you will also find the app invaluable in getting everything tuned.

If you end up keeping the Alpine tweeters, you will likely need to match there output level to whatever you end up with in the kick-panel. This is a strong argument for going with a component set where this has already been done for you. If the provided crossover has a level adjustment it will be much easier and you can look at the upper frequency response in the RTA plot to tell when it's right. If you don't have a level adjustment, you will need to figure out how much attenuation you need and build an l-pad circuit to get it right.

Your going to have a hard time getting decent low end out of 5.25" speakers. Low-cost (and some high cost) 5.25" 2-way coax and component sets tend to have low response below 100Hz (or even higher). This is a big part of the argument for the e34 drivers as they have *decent* (but not spectacular) low end. The e34 low end is probably better than your Kenwoods or Cerwin Vegas. This may however not be true for the rest of the speaker range. So if you want good sound be prepared to add a subwoofer. In the e30 coupe this is pretty easy (I have a convertible which is not). A small sealed box shooting through the ski-pass with an 8" or 10" sub will add what you need. If your not up to building the box get this one: http://www.germanaudiospecialties.co...enclosure.html or the 10" or 12" version.

You will also improve sound dramatically by adding an AMP. I'm using a Precision Power Black ice 4 channel/1600 watt for the main speakers and a 1300 watt monoblock from the same line for the sub. I've found these to be decent quality and can be had for about $80 each.

That should give you plenty to think about. Depending on the quality of sound you want there's a lot more to consider such as sound dampening (dynomat), active vs passive crossovers (I wish now that I'd gone with active), sound processing/equalizations (to compensate for the zany way sound bounces around and resonates in the cabin), etc.

Good Luck....

Thank you so much! I guess the Alpines aren't the best solution. This particular set does not have a level control.

I actually just finished up a subwoofer (mounted in ski pass) and 5 channel amp install today. I'm still working on tuning the amp but so far I'm blown away. The stock tweeters are sounding worse though. Maybe they're blown? I did find a little capacitor wired in behind them.

I'm really looking to buy a proper 2 way component set. The e34/Dayton combo is not really an option since I don't know how to build crossovers. I'd rather just get a decent aftermarket set. I've seen some forum members using the Pioneer Ts-d1320c but I'm unsure of how the tweeters will fit in the sail panels.

[pgaustin]

Glad to help! The pioneers look pretty good. You might be able to fit those tweeters into the sail panel housing. If not, you could find a set of panels without the tweeter housing and mount externally to those...