What crossovers should be used with the NX30?

Also what other options does anyone see for mounting positions for another set of tweeters?

 

Sun stroke,

For now I plan to use the capacitor that is already there for the 2" Bose Tweeter which is also 4 ohms.

Since both speakers are 4 ohms, the first order crossover point will be the same at 2KHz.

From there I plan to do a spectrum response to see how to proceed with a 2nd order design.

Because the NX30 can go down to 2KHz faithfully (when most 1" tweeters can not), there is no reason to keep the Bose tweeter. I will be mounting the NX30 in the same location. that Bose was in.

-Mr. Wigggles

 

Well, I re did somethings and it sounds a lot better. I reinstalled the tweeters so they are not pointed directly at me anymore. I had the do some cosmetic stuff to hide the previous mounting holes with some vinyl but it came out OK.

Before I remounted them, I could shut my eyes and pretty much point to the tweeter, they were much too apparent.

Now the sound is much more balanced and I am happy with the install.

 

nice dugless and you added blind spot mirrors:D

 

Has anyone considered cutting a black plastic pipe in half, round off the end and use it as a sound deflector instead of installing a whole additional tweeter? I know that if I put my hand at the back of the existing tweeter, the deflection brings out the highs. So what if you just bought some plastic pipe at the same diameter as the existing tweeter, cut it to -- I dunno -- an inch or two in length. Cut that in half (to make a 'C'), then round off one end to make it look nice. Attach the other end somehow at the back of the tweeter.

Hell, that's a lot cheaper and easier, and you don't hack away at your <1 year-old car. Might at least be worth a shot.

 

I actually did that first. I fabricated a little deflector out of spray paint cap. it sounded good and helped but I needed a little more because of the sub.

 

I was thinking something very similar, but haven't got down to Home Depot or Lowe's yet to find the right kind of plastic.

Maybe I'll give a look this weekend.

 

I think adding plastic would look cheap IMO

 

Well that defeats the purpose of mounting new tweeters now, doesn't it -- the main problem with the stock tweeters is not the speakers themselves, but the way they're aimed. If I yank the stocks and flush mount new ones, I haven't changed anything.

 

duh
sorry

youre right

 

may i sugest
the ideal mounting position(for relocating and to add tweeters) would be at the corner of the dash facing upward against the windsheild so sound would reflect back in to the cabin at a wider angle
and also lift the sound stage above the dash.
any speaker mounted/pointed straight at your ear is as bad as wearing one sideed headphone.

 

I added the Image Dynamics NX30s without any problems.

First I did some listening tests:



The results were very good. It is very easy to audition them since they are magnetic and stick right to the metal. Because Bose has HEAVY equalization in the 10KHz on up for their tweeter, I used the factory angling technique which doesn't shoot the tweeter right at the listener. This increased off-axis angle helps reduce the upper trebble. So I just mounted them right in the hole the Bose tweeters came out of with the facotry capacitor in series:



That little piece of metal comes with the tweeters and I used it as a bracket to hold the tweeter in place. Once the tweeter pod is snapped back into place you would never know that any modification had occured except for one thing: they sound a lot better! I found it sounded much more enjoyable as a direct replacement.

But the heavy Bose equalization was still a little too much in the 10KHz+ range even with the high factory off-axis angling. So, I did a little simple acoustic dampening to reduce those frequencies. I took a black cotton t-shirt and cut two little circles out of it. I then sandwiched the cloth circles between the tweeter and the plastic grill - even better results. (Ps. reducing the treble output on the tone controls effects everything from 3KHz+ which is not desirable. I just wanted to reduce the upper trebble where the Bose equalization kicks in). Not bad for $120 and 2 hours of work.

-Mr. Wigggles

Ps. I have already ordered Dolby Prologic II decoder. If I go that route, and use seperate amplifiers and get rid of the Bose amps, the Bose equalization won't be there and I won't need in dampening. I am not sure though because the Bose system now sounds real good!

 

I knew that tweeter would work! :D

I wouldn't put tweeters up in the corners of the dash pointing straight up. You will only hear the one closest to you and that just doesn't sound right. Ideally you want to get your speakers the farthest away from you that you can. If you want to smoothen out the sound even more than just replacing the tweeters, install them in the a-pillars above the dash firing across the dash. Tweeters don't have to point at you to be effective. The logic for installing them in the pillars is based on distance. Measure the disatnce from your head to the door speaker. Now measure the distance from your head to the tweeter. Much closer isn't it?! Ideally you want these to be the same dostance from your ears for time alignment. The closer they are to the same distance, the less work the equalization will require to fix the peaks and valleys in frequency response. Now measure the distance from you head to the a-pillar. It may not be equal to the distance to the door speaker but it should be much closer. I can easily fabricate an a-pillar that you'd never know didn't come that way from the factory.

If you want to take it one step farther and don't want to use the Bose mids anymore, there is an easy way to make fiberglass speaker enclosures inside the doors. Go to a new home constrution site and get some scraps of blue or green foam wall insulation. Here is Houston they install this before the brick. You can also get it new at your home improvement store since it is only about $8 for a 4' X 8' sheet. You shouldn't need this much though which is why I say get scraps. This foam is very easy to cut with a knife. Cut it to the desired shape and then stack pieces together until you have the thickness desired. Use wood glue to attach each foam piece together. For any fine edges you can just use sandpaper to shape the new foam shape you've made. This will be your mold and should look like what you want the box to look like. After it all is shaped, line the entire piece of foam with masking tape. Make sure to cover it entirely as fiberglass eats foam very quickly. Take some carnauba car wax (not the liquid) and wax all the tape then start laying piberglass down in layers over the entire mold. Don't worry about cutting any holes yet. Take your time with this step. Do several thin layers of fiberglass. The key is in using as little resin as you can with as much mat as you can and still getting it all covered and smooth. If you call me I'll give you tips and if you are in Houston I'll help you build it! After you have all the layers done and you are satisfied with your work, cut out a circle in the fiberglass for the speaker. You could have also used a wooden front plate and glassed to it. Now pour some Acetone through the speaker hole. This will dissolve the foam mold. Just pour it out. Now reach in and remove the tape remnants. Add a little sound dampening to the back, and maybe a little polyfill and you have an enclosure! It sounds tough but is actually quite simple. Depending on how big you can get the enclosure and what type of mids you have, I could even possibly tell you how to port it for some great low end entension. Anyways sorry for the lesson in fiberglass 101. I just thought that it was the next natural progression. Once you start changing the sound it is hard to ever be satisfied. That's how I got to be an installer for so many years!

 

Much of the problem is the space. As you can see with those that have already mounted speakers, the spatial area is a tight. You need to keep the original speaker and it is not a tweeter - another problem and the reason for the addition to begin with.

I agree with the looks. I played with where to put them for some time. I really like the last pic here where the guy moved them. One thing though as far as looks, not all speakers look good at the same angle. My speakers looked horrible to me from a side angle- they have a snap mount so I had to consider that along with sound direction. Mine do not face me directly but rather more toward the steering wheel and the front area. I mounted them low to conceal the side view. The sound is good . I really like those dome-like speakers someone showed here too. In my area I was only able to find what I bought and what Spin9K recommended and I had to drive 40 miles to get those.

The sound quality is improved and that surely is the goal of everyone. A tweeter is needed. Rotarygod, they are piezos and they are cheap but as you said, that tweak of tweet is all my ears need. I hear the cymbal brushes and the crispier sounds now - all for $20!

 

I have stated the following before

The factory 2 inch tweeter is 4 ohms nominal and has 22 microfarad capacitor in series with it. That means it is highpassed at 1800 Hz, period. So that's criteria: finding a replacement that can do 1800 Hz to 20 KHz

Finding a real tweeter that goes down that low is difficult but not impossible so you don't need to keep the factory tweeter. The NX30 can go down to 1 KHz so having NX30 crossed at 1800 Hz suits it just fine. Also since the diaphram is only 1.25" wide, it can stil go up to 20KHz, where a 2" paper cone tweeter simply can't.

If you haven't seen my install pics above, please do.

Now the NX30 isn't $20 that's for sure, but since it is a direct replacement we agree it looks a lot better. (I think it will sound better than an add-on tweeter, but there is no way to prove that without some side-by-side listening tests.)

-Mr. Wigggles

 

So, Mr. Wiggles --

I can't thank you enough for the advice about the NX30s. I ordered them last week and installed them last night and *holy crap* what an incredible improvement.

You can't tell I made any changes in the car until you turn on the radio... Installing them took about 40 minutes... couple snips, a little quick soldering job and you're in business.

I really can't believe what a profound difference adding these tweeters has made.

Thanks again Wiggles!

Matt

 

Could someone explain the Spin9k's directions, or translate them for the layman? My knowledge of circuits is rusty.

Also, what are decent 1khz 1" tweeters <50$ and where can i get them?

and does crossover refer to the point where the 2nd speakers take over, frequency wise? What happens if speakers overlap frequency ranges?

 

A crossover is an active or passive device designed to limit frequencies from above or below a certain frequency from reaching a speaker. So in English it means that certain frequencies are not allowed to get to a certain speaker. A tweeter wants a crossover at a higher frequency than a woofer does. A crossover can also block either high or low frequencies.

Technically all speakers will overlap in frequency since the crossover blocks frequencies at a certain rate per octave. You can't just completely stop every frequency from reaching a speaker. If a crossover has a slope of 12 db per octave, this means that if a tweeter is crossed over at 2000 hz, at 1000 hz the sound coming out of it is 12 db lower in intensity. What you are referring to when you ask what happens when speakers overlap frequencies is really dependant upon a couple of things. First of all, how loud are the frequencies that overlap in relation to each other from the other speaker? If the speakers are exactly the same distance away from your ears then this may not do anything bad. Then again maybe it will create a severe dip in output around that frequency or it may cause a big peak. There are many variables to that.

I don't even know of a decent tweeter for under $50. Most of the good tweeters out there don't want to play down to 1000 hz. This is very hard on a tweeter and the crossover slope needs to be steep. Somewhere around at least 24 db per octave.

 

so, can anyone provide step by step directions 'for dummies' ?

 

So let me summarize what I've gotten out of this thread thus far. 5 possible solutions:

1) Radio Shlock surface mount tweeters, ~$20 pair, augment pillar speakers, hooked in parallel using same crossover

2) Kenwood surface mount, price not given, hooked in parallel using same crossover. Also take the 2" Bose speakers out of their mount and used an Exacto knife to shave off the high side of the hole they mount into. Doing that directs the sound from pointing into the dash and directed it more towards your head.

3) JL Tweeters surface mount, price not given, hooked in parallel using same crossover.

4) Cutting a black plastic pipe in half, round off the end and use it as a sound deflector instead of installing a whole additional tweeter?

5) Image Dynamics NX30s, $120 pair, replace pillar speakers completely http://www.sounddomain.com/sku/IDSNX30

Sounds to me like the best solution, for my tastes anyway, is to bite the bullet and get the Image Dynamics NX30's to replace the pillar speakers completely. Just looks the neatest, while retaining the best sound compromise with the existing Bose amps and head unit.

So my question for Mr Wiggles is this: Did you do any angling of the NX30s so they point more toward the driver, much as was done in option (2) above?

Thanks...

 

He just did a straight replacement of the stock tweeters. They are still pointed the same.

 

Omicron,

Using the NX30 is a pretty straightforward exchange.

As far as angling is concerned, when you mount the tweeters, they are a pressure fit. You could put some sort of little standoff to angle the tweeter.

However, the upper frequencies (10KHz +) are pretty bright so leaving the unit the factory highly off-axis angle isn't such a bad idea. Like I said before, I used a small piece thin black t-shirt to do some additional high frequency attenuation.

Bottom-line you will probably fine something that works for you. If you don't damage the hardware that comes with the tweeter (namely the metal bracket), you can always return it to sounddomain for a full refund.

-Mr. Wigggles

 

Thanks MrWiggges and Rotarygod, that's helpful. Guess it's off to Sounddomain to get some NX30s!

 

BTW,

On the NX30's, they come assembled (without any disassembly instructions).

It may sound stupid but just so you know the front mounting ring screws off. It took me a awhile to figure that out.

-Mr. Wigggles

 

Well I put in a pair of NX30's tonight. Gawd, what a difference!! Noticed a little brightness on the high end similar to that reported by MrWiggles. I'll try his solution when I get some more time to tweak it.

I had trouble getting a pressure fit to stay put so I ended up using some black electrical tape to hold the tweeter in place. Used a Q-tip to apply the tape in the tight spots.

Now that the NX30's are in, I notice the muddyness of the front door midwoofers. The other thing that drives me nuts is the amplifier hiss I can now hear with the tweets. It's objectionable. You'd think this was a 1970's POS KMart amp. Guess I'm being too picky since the hiss will get swamped by the road noise. No high, no lows, it must be Bose