Altec N800F and N800-8K Circuit Crossover:
In addition to Hiraga Circuit Crossovers, and custom crossovers, I offer crossovers using Altec's circuit for second order (12 dB per octave slopes) the N800F and N800-8K crossovers, adapted for use with an L-pad for tweeter level control, as opposed to the rheostat used by Altec. The Lpad provides better control than the rheostat.
The N800F is a 16 Ohm crossover. It was used by Altec for speakers with combinations of 8 and 16 ohm speakers. It works well with the following woofer/tweeter impedance combinations: 16 Ohms/16 Ohms, 16 Ohms/8 Ohms, 8 Ohms/16 Ohms, and 8 Ohms/8 Ohms. That said, if the primary application is an 8 Ohm two way system, I would be advise the user to order the Altec N800 K version of the crossover
The N800F is a 16 Ohm crossover, It was used by Altec for 16 Ohm 846A model Valencia speakers
The N800-8K is an 8 Ohm crossover. It was used by Altec for 8 Ohm 846B model Valencia speakers.
Applications of the 16 Ohm N800F crossover to speakers with 16 Ohm nominal impedances:
Altec used the N800F circuit with the 811 horn for the A7-800 VOT speakers, as well as
846A Valencia, Flamenco, Capistrano, and Milano, speakers. These are all speakers with 16 Ohm woofer and tweeter impedance. Altec used the N800F circuit for Malibu speakers which use two 16 Ohm Altec 416 woofers per channel in parallel, for an 8 Ohm load on the low pass filter, and a 16 Ohm compression driver for the 811 horn, for a 16 Ohm load on the high pass filter.
Calculated 16 Ohm N800F electrical response curves with 16 Ohm woofer and tweeter:
The calculations presented below are for the 16 Ohm N800F circuit with 16 Ohm woofer and tweeter loads. The crossover calculated electrical response curves for the 8 Ohm N800-8K circuit with 8 Ohm woofer and tweeter loads are the same as those shown below.
Here are calculated electrical response curves for the Altec N800F circuit 16 Ohm crossover using an L-pad for tweeter level control. These calculations are for the case with 16 Ohms nominal impedance for the woofer and tweeter. The first curve below has the tweeter set (by the L-pad) at the same sensitivity as the woofer. The second curve has the tweeter set 4 dB above the woofer. The third curve has the tweeter set 4 dB below the woofer:
In addition to Hiraga Circuit Crossovers, and custom crossovers, I offer crossovers using Altec's circuit for second order (12 dB per octave slopes) the N800F and N800-8K crossovers, adapted for use with an L-pad for tweeter level control, as opposed to the rheostat used by Altec. The Lpad provides better control than the rheostat.
The N800F is a 16 Ohm crossover. It was used by Altec for speakers with combinations of 8 and 16 ohm speakers. It works well with the following woofer/tweeter impedance combinations: 16 Ohms/16 Ohms, 16 Ohms/8 Ohms, 8 Ohms/16 Ohms, and 8 Ohms/8 Ohms. That said, if the primary application is an 8 Ohm two way system, I would be advise the user to order the Altec N800 K version of the crossover
The N800F is a 16 Ohm crossover, It was used by Altec for 16 Ohm 846A model Valencia speakers
The N800-8K is an 8 Ohm crossover. It was used by Altec for 8 Ohm 846B model Valencia speakers.
Applications of the 16 Ohm N800F crossover to speakers with 16 Ohm nominal impedances:
Altec used the N800F circuit with the 811 horn for the A7-800 VOT speakers, as well as
846A Valencia, Flamenco, Capistrano, and Milano, speakers. These are all speakers with 16 Ohm woofer and tweeter impedance. Altec used the N800F circuit for Malibu speakers which use two 16 Ohm Altec 416 woofers per channel in parallel, for an 8 Ohm load on the low pass filter, and a 16 Ohm compression driver for the 811 horn, for a 16 Ohm load on the high pass filter.
Calculated 16 Ohm N800F electrical response curves with 16 Ohm woofer and tweeter:
The calculations presented below are for the 16 Ohm N800F circuit with 16 Ohm woofer and tweeter loads. The crossover calculated electrical response curves for the 8 Ohm N800-8K circuit with 8 Ohm woofer and tweeter loads are the same as those shown below.
Here are calculated electrical response curves for the Altec N800F circuit 16 Ohm crossover using an L-pad for tweeter level control. These calculations are for the case with 16 Ohms nominal impedance for the woofer and tweeter. The first curve below has the tweeter set (by the L-pad) at the same sensitivity as the woofer. The second curve has the tweeter set 4 dB above the woofer. The third curve has the tweeter set 4 dB below the woofer:
Listening tests with the 16 Ohm N800F circuit and 16 Ohm speakers:
I have listened to my version of the 16 Ohm Altec N800F Circuit with Altec Valencia speakers using the Altec 416 woofers and the 811 horn. The Valencias were favorites of late great audio writer and reviewer Art Dudley. In my opinion the Valencias are not quite the equal of the A5 and A7 VOT speakers, but they are quite wonderful, are small enough to complement many rooms, and have great eye appeal. My N800 crossovers with good capacitors and good inductors offer a sweetness and musicality not provided by the stock crossovers.
I have listened to my version of the 16 Ohm Altec N800F Circuit with Altec Valencia speakers using the Altec 416 woofers and the 811 horn. The Valencias were favorites of late great audio writer and reviewer Art Dudley. In my opinion the Valencias are not quite the equal of the A5 and A7 VOT speakers, but they are quite wonderful, are small enough to complement many rooms, and have great eye appeal. My N800 crossovers with good capacitors and good inductors offer a sweetness and musicality not provided by the stock crossovers.
Applications of the 16 Ohm Altec N800F circuit crossover with unequal woofer and tweeter nominal impedances:
Altec succesfully used the 16 Ohm N800 crossover with the Malibu speakers which have a 16 ohm tweeter and a pair of Altec 414 12 inch,16 Ohm woofers connected in parallel, giving a woofer load of 8 Ohms. Response curve simulations of the 16 Ohm N800 circuit with a 16 ohm tweeter and an 8 ohm woofer provide a very satisfactory response curve. The crossover is at 1 kHz, with a broad 2 dB dip centered at 900 Hz.
Altec's use of the 16 Ohm N800 circuit with an 8 Ohm woofer load and a 16 Ohm tweeter load suggested considering all combinations of 8 and 16 ohm woofers and tweeters with the 16 Ohm N800 circuit. Therefore I did studies which reveal that the 16 Ohm version gives a desirable frequency response with mixed or matched 16 Ohm and 8 Ohm drivers. In all of these cases the response is reasonably flat through the crossover, with less than the 3 dB response variation one would find with a Butterworth second order crossover. This begs the question whether it is necessary to provide 8 Ohm nominal versions of the N800 network. An 8 Ohm N800 network driving 8 ohm loads has a +2 dB response bump.
A 16 Ohm N800 network used by Altec for the Malibu speakers with 16 a Ohm network tweeer load and an 8 Ohm woofer load the crossover point is 1135 Hz, and the response variation is a 2 dB response dip.
For a 16 Ohm network loaded with various combinations of 8 and 16 ohm woofers and tweeters the crossover point and response variation are as shown in the following table:
16 Ohm N800 Network Response deviations:
Woofer Tweeter Crossover Point Response Variation, dB
Impedance Impedance
16 16 1135 Hz bump +2.0/-0.0
8 16 890 Hz dip +0.0/-2.0
8 8 900 Hz dip +0.0/-1.5
16 8 900 Hz dip +0.0/-1.8 dB
These response variations are in the vicinity of the crossover frequency. They are smaller than the +3 dB variation inherent in the textbook Butterworth second order networks sometimes used in Altec crossover designs.
Altec succesfully used the 16 Ohm N800 crossover with the Malibu speakers which have a 16 ohm tweeter and a pair of Altec 414 12 inch,16 Ohm woofers connected in parallel, giving a woofer load of 8 Ohms. Response curve simulations of the 16 Ohm N800 circuit with a 16 ohm tweeter and an 8 ohm woofer provide a very satisfactory response curve. The crossover is at 1 kHz, with a broad 2 dB dip centered at 900 Hz.
Altec's use of the 16 Ohm N800 circuit with an 8 Ohm woofer load and a 16 Ohm tweeter load suggested considering all combinations of 8 and 16 ohm woofers and tweeters with the 16 Ohm N800 circuit. Therefore I did studies which reveal that the 16 Ohm version gives a desirable frequency response with mixed or matched 16 Ohm and 8 Ohm drivers. In all of these cases the response is reasonably flat through the crossover, with less than the 3 dB response variation one would find with a Butterworth second order crossover. This begs the question whether it is necessary to provide 8 Ohm nominal versions of the N800 network. An 8 Ohm N800 network driving 8 ohm loads has a +2 dB response bump.
A 16 Ohm N800 network used by Altec for the Malibu speakers with 16 a Ohm network tweeer load and an 8 Ohm woofer load the crossover point is 1135 Hz, and the response variation is a 2 dB response dip.
For a 16 Ohm network loaded with various combinations of 8 and 16 ohm woofers and tweeters the crossover point and response variation are as shown in the following table:
16 Ohm N800 Network Response deviations:
Woofer Tweeter Crossover Point Response Variation, dB
Impedance Impedance
16 16 1135 Hz bump +2.0/-0.0
8 16 890 Hz dip +0.0/-2.0
8 8 900 Hz dip +0.0/-1.5
16 8 900 Hz dip +0.0/-1.8 dB
These response variations are in the vicinity of the crossover frequency. They are smaller than the +3 dB variation inherent in the textbook Butterworth second order networks sometimes used in Altec crossover designs.
Calculated 16 Ohm N800F electrical response curves with 16 Ohm tweeter and 8 Ohm woofer (as in the Malibu):
Here is the calculated electrical response curve for a 16 Ohm Altec N800F circuit crossover using an L-pad for tweeter level control. This is a special case calculated for the Altec Malibu speaker or other speakers with a 16 Ohm nominal tweeter load and an 8 ohm nominal woofer load. The crossover point is 900 Hz, with a 1.8 dB dip. The curves shown below are calculated for the case where the tweeter with its L-pad is set to the same sensitivity as the woofer.
Here is the calculated electrical response curve for a 16 Ohm Altec N800F circuit crossover using an L-pad for tweeter level control. This is a special case calculated for the Altec Malibu speaker or other speakers with a 16 Ohm nominal tweeter load and an 8 ohm nominal woofer load. The crossover point is 900 Hz, with a 1.8 dB dip. The curves shown below are calculated for the case where the tweeter with its L-pad is set to the same sensitivity as the woofer.
Listening tests with the 16 Ohm N800F circuit driving an 8 Ohm woofer and 16 Ohm tweeter, using the Altec A7-500-8 speakers:
To emulate the Altec Malibu speaker, with an 8 Ohm woofer load and a 16 Ohm tweetere load, I added a series 8 Ohm resistor to the 8 Ohm tweeter of my 8 Ohm Altec A7-500-8 speakers and listened to the results, which were captivating. I could not have been happier with the listening results. I do not hesitate to recommend my 16 Ohm Altec N800F circuit crossover with 16 Ohm Altec A5 or A7 speakers, 8 Ohm Altec A7-500-8 speakers, or with other two way speakers that can perform well crossing over at any frequency between 890 and 1135 Hz. On the other hand, if the primary use for the crossover is with 8 Ohm woofer and tweeter loads, I recommend using the N800-8K circuit.
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Pete Riggle Audio
2112 S. Olympia Street, Kennewick WA 99337, USA
shop phone: 509 582 4548 email: peteriggle@msn.com
VTAF™ Trademarked. U.S.Patent No. 7630288.
Website content Copyright © 2021 Pete Riggle Audio, All Rights Reserved.
Pete Riggle Audio
2112 S. Olympia Street, Kennewick WA 99337, USA
shop phone: 509 582 4548 email: peteriggle@msn.com
VTAF™ Trademarked. U.S.Patent No. 7630288.
Website content Copyright © 2021 Pete Riggle Audio, All Rights Reserved.