4 Ohm woofer 8 Ohm tweeter

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Hi all, I've been a member for quite awhile now, but I mostly just read the threads to gain some knowledge. I haven't been able to contribute much, with my limited knowledge. I do however have a question I hope someone will consider. In my youth I purchased a pair of Pyrimid 8" 4 Ohm speakers rated at 100wrms with a frequency responce of 41Hz to 2.5KHz I never used them much, maybe 20hrs. with indash car HU power, maybe 15 watts. Now I would like to use them in a in house stereo application. I built a pair of sealed enclosures @ .75 cubic ft. I havn't chosen a tweeter yet, but would like to use an 8 Ohm tweeter, I would like to show an 8 Ohm load or therabouts to my amp a pioneer SA-9500 as not to stress the amp with to low of a load. Parts express sells the Dayton 2-way crossover that you can use a 4 Ohm or an 8 Ohm woofer with, for a cost of $24.00 per X 2. I would like to keep the cost down. I was wondering if any speaker manufacturers made production speakers with this type of configuration, the 4 Ohm woofer and 8 Ohm tweeter, that I could look for as a used replacement. I thought I read somewhere that this was not all that uncommon. Does anyone have any cheap Ideas or cost effective suggestions as to what might fit my requirements?. What would happen if I just used a generic 2k 2 way crossover?, would I put my amp in peril, would I have speakers that were unlistenable?. Sorry about the length of my post. Thanks to all who reply, all suggestions and ideas are very welcome. Jed
 
So, if we decipher the lack of paragraphs and uneeded ramblings we are left with;

"how can I build a two way speaker using a 4ohm bass driver to present an easy load for an integrated amp ?"

Get the parameters for the bass driver.
Use winisd (or similar) to design the bass enclosure.
Find a tweeter that matches the bass driver.
Install tweeter in enclosure.
Measure (if able to) frequency responses of each driver.
Make crossover to suit.
Final tune by ear.

In regards to the amp, you do realise that some speaker systems can dip down to 2ohms or lower.
The impedance curve that the amp will see from the speaker is a combined function of the speaker drivers and the crossover.
In essence I wouldnt be worried unless your planning on driving the amp into clipping on a regular basis.
 
well I think a basic calculation would be a 6ohm speaker but I would not be suggesting running a 4ohm woofer if your amplifier wants to see a 8ohm load.

A generic crossover like your thinking is expecting both speakers to be equal.
Say if you had a 6db/oct crossover at 4.0k intended for 8 ohm speakers.
Your tweeter would be crossed over correctly but if you used a 4ohm woofer it would be crossed over at 2.0K so you would have a large dip in your frequency response. in order to correct this you need a inductor(lowpass) of half the value they used.
I would guess you would have a peak and dip response if tried with a higher order crossover but am unsure.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.