[arjyamaj]

Hello, I searched all over this forum for a related thread but didnt seem to find a thread that would relate to this. So here goes.

A long time ago, I used to play the electric guitar. I had a SWEET sounding amp (a four channel Stranger 60) and a custom-made speaker enclosure consisting of a 12" sub, a 10" woofer (both Mekasonic) and two 2.5" dome tweeters (Philips). To give you an idea of the clarity of music this would produce- at a mini concert, I could plug in my guitar, a bass guitar, a keyboard and a mike (for vocals) and members of the audience standing atleast 20 metres away would be able to hear every note perfectly inspite of using all four channels. A very well balanced sound.

But that was a long time ago. Life in a law firm took its toll. I no longer play electric. The amplifier no longer works. The speakers, however, were recently rediscovered during a spring cleaning session and seem to have no issues. Except for the sub- which fell victim to an over enthusiastic overdriven bass guitar during one rehearsal- which essentially tore the diaphragm.

So here's the idea. Can the tweeters be used in my car? My current setup is a very-basic-competent-at-best JVC HU, JBL GT5-S204 in the front and a pair of 6x9 Xplods (shudder!) in the rear. Yes, I swear to change the HU and the rear speakers soon (to hopefully a Pioneer FH-P6050UB and Polk db 691s respectively). But that's a different story.

These tweeters used to be made for professional musicians but Philips have stopped making them. The reason why I'm so gung-ho about this is that the high notes on a guitar solo, even with overdrive and all that would come out crystal clear. So, does it make sense to add them to the existing setup I have? Perhaps splice the front wires?

Another thing. I drive an alto. Assuming that I do go ahead with this, where would you recommend I place them? These tweeters come with flush mounts (about 4" square) and have drill holes to affix them.

Oh and, since I have no use for the 10" speaker, I'd be willing to give it away- in return for good advice (or a free install of the said tweeters) of course

Thanks for having the patience to read through this. And I look forward to any suggestions that may come this way.

[CrackedHead]

Hmm, I'm no expert but here goes.

Does your HU have crossovers - A basic High Pass Filter ? You could run the tweeters off the front two outputs (with the internal amplifier of the HU). Use the HPF and fader to adjust the tweeters to your liking. There are several options for mounting them - could be in your door pads or on the A pillar/dash. Search and you'll find several threads about that.

Get a small 2 channel amplifier (about 3K) and you can bridge that and power the the 10" sub with it to play the lower frequencies. This should work if the speaker's impedance is 4 Ohm's or higher. You can figure out a suitable enclosure if you have the specs for this speaker.

[MaveRick4x4]

That's tad cheeky and innovative.

You can make it into a dual mode use type.
Pack a Toggle switch to shift between:

- A practice station, if you are musician
- old ICE for playing music.

I have a Peavey stack, wondering what would happen to my soft top j.e.e.p, back then?
A sonic boom on the Stack and the side flaps open up, sounds animated.

Congrats again, post pictures and let everyone know your innoative ways on ICE.

MaveRick4x4

[navin]

Originally Posted by CrackedHead

Does your HU have crossovers - A basic High Pass Filter ?

Get a small 2 channel amplifier (about 3K) and you can bridge that and power the the 10" sub with it to play the lower frequencies.

Originally Posted by arjyamaj

10" woofer (both Mekasonic) and two 2.5" dome tweeters (Philips).
Can the tweeters be used in my car? My current setup is a very-basic-competent-at-best JVC HU, JBL GT5-S204 in the front and a pair of 6x9 Xplods (shudder!) in the rear.

ok we need to control 3 things here.

a. relative sensitivity of the tweeters vis-a-vis the front speakers.
b. filter the tweeters so that they are not overlaoded
c. tonal balance of the system

a. you will need a 4 or 10 ohm/10W resistor in series with the tweeter
b. if you have the tweeter section of the crossover from your guitar amp you can use this and then insert the 4/10 ohm resistor between the amp and XO.
c. you might have to remove the tweeter of the S204 as the whole sound with both pairs of tweeters going (S205 + philips) might be too forward.

[Sam Kapasi]

Originally Posted by CrackedHead

Does your HU have crossovers - A basic High Pass Filter ?

One does not necessarily need an active HPF to run a tweeter. You could very well bung in them to parallel with the speaker, provided you put a bipolar capacitor in series (i.e. on any one lead of the tweeter)
Depending on the crossover you wanted to achieve, it could be anything between a 2.2mfd to 6.3mfd bipolar cap.
This is ofcourse assuming you are only succesful in removing the tweeters and not the passive crossover in your guitar amp.

Also as Navin says, you should expect to connect a 4.7 to 8.6Ω 10/15W resistor in series, along with that bipolar cap.

I do not expect your guitar amp tweeters to sound good in your car though.. my opinion.

[navin]

Originally Posted by Sam Kapasi

Also as Navin says, you should expect to connect a 4.7 to 8.6Ω 10/15W resistor in series, along with that bipolar cap.

get a non-inductive resistor. You will find them in 1/2/4/10 ohm 10W ratings.

[arjyamaj]

Thanks guys, much much appreciated!

Originally Posted by navin

ok we need to control 3 things here.

a. relative sensitivity of the tweeters vis-a-vis the front speakers.
b. filter the tweeters so that they are not overlaoded
c. tonal balance of the system

a. you will need a 4 or 10 ohm/10W resistor in series with the tweeter
b. if you have the tweeter section of the crossover from your guitar amp you can use this and then insert the 4/10 ohm resistor between the amp and XO.
c. you might have to remove the tweeter of the S204 as the whole sound with both pairs of tweeters going (S205 + philips) might be too forward.

Originally Posted by Sam Kapasi

One does not necessarily need an active HPF to run a tweeter. You could very well bung in them to parallel with the speaker, provided you put a bipolar capacitor in series (i.e. on any one lead of the tweeter)
Depending on the crossover you wanted to achieve, it could be anything between a 2.2mfd to 6.3mfd bipolar cap.
This is ofcourse assuming you are only succesful in removing the tweeters and not the passive crossover in your guitar amp.

Also as Navin says, you should expect to connect a 4.7 to 8.6Ω 10/15W resistor in series, along with that bipolar cap.

I do not expect your guitar amp tweeters to sound good in your car though.. my opinion.

Makes sense. Unfortunately, I wouldnt be able to salvage the tweeter crossover from the amp (its a tube based amp, not a transistor based!). However, I'm completely at sea with the usage of the capacitor with a passive crossover as opposed to an active one. Never mind, I'll read up on that shortly.

A very basic (and therefore possibly stupid) question- the tweeters are rated 4 Ω 15 W. Would I still need a resistor?

@ Naveen, wrt your suggestion of removing the tweeters from the JBL GT5s, I'll take a call on that once the system is up and running. I have a feeling it wont be as forward as we thought before. Or I could place them somewhere post the B pillar perhaps?

@ Sam Kapasi- wrt the sound quality, any particular reason why?

Originally Posted by MaveRick4x4

A sonic boom on the Stack and the side flaps open up, sounds animated.

Congrats again, post pictures and let everyone know your innoative ways on ICE.

MaveRick4x4

A mobile rock concert perhaps? and yeah, I'll take pics during the install.

[navin]

Originally Posted by arjyamaj

A very basic (and therefore possibly stupid) question- the tweeters are rated 4 Ω 15 W. Would I still need a resistor?

if you cannot remove the passive XO that is between the tube amp and tweeter then you will need a 4.7uf cap in series with the resistor.

[arjyamaj]

In spite of somewhat lukewarm responses to this idea, I plunged ahead anyway. This post is in two parts. One is an update on what's happened since 2010. The other is the proposed way forward and queries related to the same.

Part 1: Here's what's happened so far.

The 12" subwoofer was repaired thoroughly and installed in parallel to the rear speakers. While this did augment the midbass, I wasnt getting the 'kick' I wanted.

What if we tried a better head unit?

The old JVC was scrapped and a second hand Pioneer FH-P6050UB 2DIN was bought from a fellow BHPian. Details of the HU may be found here- here.

The sound quality got much better. The salient features of this HU (for the purposes of this post) are as follows:

1. High pass filter, which can be adjusted within a range of 50Hz to (I think) 100Hz
2. Subwoofer control, including a low pass filter
3. 2 (4V) preouts

However, apparently the subwoofer control works only when the HU is connected to an amp. Nevertheless, I tried connecting the sub directly to the sub-output on the HU.

Nothing happened. *sigh*

So, it was back to the sub being connected in parallel to the rear speakers.

This worked somewhat for a while (after many permutations on the equaliser and the fader controls), but then the rear speakers began to show their age.

Enter the Alpine SPJ-69C3.

I installed a pair a few months back. They're nice, but they ARE entry level 6x9s. Overall, am pretty satisfied with the present setup.

Here's what it looks like right now.



Just to recap
Headunit- Pioneer FH-P6050UB
Front Coax- JBL GT5-S204
Rear Coax- Alpine SPJ-69C3
Subwoofer- Mekasonic GP-12B

Part 2: Now, this is what I would like to do.

I still have the smaller 10" subwoofer (Mekasonic GP-10B) and a pair of tweeters (Philips). I was thinking of adding them too, but I know that there's no way I can run all eight speakers off the HU.

So, I need an amplifier. This forms the basis for my question, which I will ask later.

Assuming I did get an amplifier, the plan is to:
1. Run the two subs through the amplifier
2. Run the two tweeters in parallel with the JBLs (these can be installed in the front doors)
3. The rear Alpines remain untouched

This is what it should look like:



Now, the question for the gurus.
1. Will a 2 channel amplifier suffice for this?
2. Or would I HAVE to get a 4-channel amp and bridge into one channel for each amp?
3. Or separate amps for each?

Vitamin M is obviously a concern here. Also, (and this is slightly ) my wife is hearing impaired and uses a hearing aid. She does get uncomfortable with loud, low frequency sounds. So, I dont need something that will be loud.

What I need is a setup that reproduces sounds across the hearing spectrum with substantial clarity, especially at low volumes.

So, I'm not to keen on a bridged 4 channel or separate amps for each sub. Therefore, the main concern is- would a 2 channel amp suffice?

Thanks for reading through this!

[DerAlte]

* I assume the sub and the woofer are 8ohms. If so, you should be connecting them in parallel, and driving them off bridged channels off a 2ch. I would of course go for a 4 ch amp, basically because a. not much price difference and b. you will need to amplify the fronts at least to get balanced sound

* Not sure of which Philips tweeters you had in mind, but if you read the earlier posts of Navin and Sam (may his soul rest in peace) have suggested that you should at least add a resistor and a capacitor (in series with one of the leads) - which serve to protect them more than anything else. Also, you have to think of how to mount the tweeters

* A 4ch amp will at least allow you to amplify the fronts and tune the system well to your requirements (the 6x9s can be driven by the HU, as they are currently). The system should sound balanced, and the bass should be just enough to be felt, or rather for it's absence to be felt. An external amp has a better ability to handle loud passages without distorting (and I am not talking of playing at a loud volume, just the loud music content at a normal volume) than the HU internal amp

* Look into the issue of "loud low frequencies" w.r.t. your wife's situation once again. I have a feeling this may be due to a. distortion produced by her set due to low frequencies (you have to try it yourself to know that), and b. the discomfort due to the vibrations & harmonics. Having a bass-heavy set up (the 6x9s plus a woofer and a sub) is not going to help in that situation at all

* Please remember, everything sounds as we put it together and tune it - a well designed system doesn't (and shouldn't be allowed to) work uncontrolled. It doesn't take much Vitamin M to figure that out and achieve it

[navin]

Originally Posted by DerAlte

* Not sure of which Philips tweeters you had in mind,

* Please remember, everything sounds as we put it together and tune it - a well designed system doesn't (and shouldn't be allowed to) work uncontrolled. It doesn't take much Vitamin M to figure that out and achieve it

I dont know when the tweeters were purchased but in the late 70's Philips used to make and sell 2 dome tweeters - a hard dome 0140 and a soft dome 0163. They also sold a 2" cone tweeter (forget the model number).

Originally Posted by arjyamaj

1. High pass filter, which can be adjusted within a range of 50Hz to (I think) 100Hz
2. Subwoofer control, including a low pass filter
3. 2 (4V) preouts

Headunit- Pioneer FH-P6050UB
Front Coax- JBL GT5-S204
Rear Coax- Alpine SPJ-69C3
Subwoofer- Mekasonic GP-12B

I still have the smaller 10" subwoofer (Mekasonic GP-10B) and a pair of tweeters (Philips). I was thinking of adding them too, but I know that there's no way I can run all eight speakers off the HU.

So, I need an amplifier.

I second DA's advice.

1. If the 2 woofers are 8 ohms each run them in parallel and use 2 ch. (of a 4ch. amp) to drive this.

2. Use the other 2 channels of the amp to drive the JBL GT5 speakers in the front.

3. Drive the rear 6x9s from the HU.

The 6x9s are more sensitive than the GT5 and besides they are loaded by a large volume (trunk) vs a small car door. Hence they require less power to produce the same sound levels as the GT5. To balance the difference in sensitivity it makes snese to supply more power to the GT5 (hence the amp).

I do not see any need for the philips tweeters. They are more liable to mess up the front sound stage than help. Besides if the philips tweeters have flanges (like the model numbers I listed above) they would be about 3" in diameter and fitting them in the front would mean significant modification to the dash or front doors.

[arjyamaj]

Originally Posted by navin

I dont know when the tweeters were purchased but in the late 70's Philips used to make and sell 2 dome tweeters - a hard dome 0140 and a soft dome 0163. They also sold a 2" cone tweeter (forget the model number).

This is the soft dome tweeter. Attaching a pic for your reference.

Originally Posted by DerAlte

* I assume the sub and the woofer are 8ohms.

Originally Posted by navin

If the 2 woofers are 8 ohms each run them in parallel and use 2 ch. (of a 4ch. amp) to drive this.

The 10" woofer is rated at 40 watts and 16 ohms. The 12" sub is rated at 80 watts and 8 ohms. Does this make a difference to your suggestions?

Thanks for the advice- much appreciated.

[navin]

Originally Posted by arjyamaj

This is the soft dome tweeter. Attaching a pic for your reference.

The 10" woofer is rated at 40 watts and 16 ohms. The 12" sub is rated at 80 watts and 8 ohms. Does this make a difference to your suggestions?

Thanks for the advice- much appreciated.

That looks like the 0163 or maybe it is the 1062 (the 62 came later in 1980-81). It should be ok at 2500/12db. Since it is fairly efficient ( about 92db) you would need to pad it down for most applications.

If you parallel 16 and 8 ohms you will get about 5 ohms. To some extent this difference will protect the 10" from over excursion as it will get less power from the amp than the 12". For example at 2.83V (most amplifiers are voltage amplifiers) you will get 0.5W in the 10" but 1W in the 12".