A7-500 horn attenuation

[altecman]

I forgot to ask in the previous thread about what attenuation is needed on the N501-8a xover for use in the A7-500 system. I worked out roughly using the Altec literature that about 6dB was needed,which is I suppose the number 3 position as this xover has a variable 20dB pot. When I use this position the horn is still too efficient, which position is a good starting point, can any other A7-500 users put me in the right direction?.

[altecman]

I can't believe that there are no A7-500 users out there that can't help me with this one simple request!!!!!!!!!!!

[Tom Brennan]

What are we supposed to tell ya? Just duke around with the thing 'till it sounds good to you like the rest of us do.

[Tom Brennan]

<font color="#FFFFFF" size="1">[ November 28, 2008 08:08 PM: Message edited by: Tom Brennan ]</font>

[SD-50]

Ok, have the A7-500 config. but I'm using a DIY 1st order x-over at 625hz so I don't know if would be of any help. The output from the horn is dropped by 4db using an L-pad. Link to a site for designing x-overs and L-pads. Hope this is of use to you.
Cheers
http://ccs.exl.info/calc_cr.html#lpad

[GM]

Originally posted by altecman:

I worked out roughly using the Altec literature that about 6dB was needed.........

<font size="2" face="Verdana, Helvetica, sans-serif">Hmm, I get ~8.44 dB difference assuming an 802/808. Regardless, pos. 5 minimum is required for the 100 W max power rating and IIRC pos. 8 is maximally flat through the XO BW, but as Tom noted, it's what sounds best in your app.

GM

[altecman]

Thanks again for all your advice but am a little confused as there are 10 positions on the N501-8, 10 being the maximum 20dB attenuation what is the standard position that Altec recommended in the home as nothing is stated in any literature. I just want to know what position (1-10) gave the most linear SPL over the frequency range.

[whitebroncoii]

I think you should understand that there is not a standard because of the many variables (system, acoustics, etc).

Start with the attenuator at mid-point and listen to a favorite piece. Make small adjustments until the balance suites you. If you listen to a wide variety of music, you may find yourself making changes for awhile. After a bit you should find a acceptable compromise and be able to leave it alone.

On the other hand, you may be like most of the us on this forum and keep changing things. Sometimes the journey is almost as important as the destination.

[bfish]

Right on. Tha's exactly why there are 10 positions instead of a permanently fixed level.

[GM]

Originally posted by altecman:
Thanks again for all your advice but am a little confused as there are 10 positions on the N501-8, 10 being the maximum 20dB attenuation what is the standard position that Altec recommended in the home as nothing is stated in any literature. I just want to know what position (1-10) gave the most linear SPL over the frequency range.

<font size="2" face="Verdana, Helvetica, sans-serif">You're welcome, I think......

And there's a bunch more in between each demarcation, but Altec's only recommendation regards power handling and I've already posted the number setting for flattest response through the XO BW IIRC which is the most technically correct thing to do and if you don't use a high output impedance tube amp, then a by-pass cap is required to 'lift up' the HF response and depending on the room and where it's placed, a baffle step compensation filter may be required to balance the mids/HF to lows if you want it tonally balanced from the lows all the way up. BTW, the M19 XO was designed to address all these issues, so for any 800 Hz VOTTs, this is an obvious upgrade when very low output impedance amps are used. I'm not aware of a 500 Hz version per se other than the 9846 piecemeal XO that only partially deals with them: http://www.lansingheritage.org/image...-8a/page03.jpg

GM