Series vs Parallel for dual Accuton Woofers

[Cousin Billy]

Hello. I am new to this forum. I have commited myself to building Tony Gee's Humble Statement speaker. I already have the four woofers (C220-T6-220), CAD program is done, wood for the CNC machine is also on the way. I realize some of you are not fond of these drivers, or the speakers. That not withstanding, my Atma-Sphere MA-1 amps will not drive the woofers if they are in parallel, 2.5 Ohm dip.

What are the pros and cons to running the woofers in series. I am in no hurry, so alot of experimentation is fine.

Any advice would be helpful.

[HiFiNutNut]

Do a title search and you will find a lot of posts stretching the past a few years from which you can find the answers.

Theoretically they will give the same response (need adjust 6dB) but in practice, many find that parallel sounds a whole lot better.

[Cousin Billy]

Thank you HiFiNutNut. Where do I look. I have done a search and cannot find relevence to series vs parallel.

[myhrrhleine]

Originally posted by Cousin Billy
Hello. I am new to this forum. I have commited myself to building Tony Gee's Humble Statement speaker. I already have the four woofers (C220-T6-220), CAD program is done, wood for the CNC machine is also on the way. I realize some of you are not fond of these drivers, or the speakers. That not withstanding, my Atma-Sphere MA-1 amps will not drive the woofers if they are in parallel, 2.5 Ohm dip.

amp oscillates?

What are the pros and cons to running the woofers in series. I am in no hurry, so alot of experimentation is fine.

Any advice would be helpful.

series can effect driver Q and thus bass response.

[elviukai]

I think you have few options-

use 2x 16 ohms c220-t6 , but you will need
a) change values (double capasistance, double less inductance)
b) lower midrange tweeter with voltage divider about 3-4db


second option (perfect which I have tried and using in studio)-
3x 12ohm c220 t6- for my opinion is perfect blend with c173n if amp can drive 4ohm load

third option (also very good , I am using this at home)

4x c220 t6 8ohm in series/paralel. this version do not have such bass slamm as 3x version but it have very friendly load(even 2a3 amp drives it hapily and in realistic bass levels and somewhat more relaxed sound(due big total area) I didnt felt that this version(paralel/series) was inferior comparing to paralel. actualy this version I prefer for clasical works , while 3x 16ohm versions is very punchy with solid state amps

c173n is realy sensitive driver(and accutron neodymium tweeter not caching up it by means of eficienty) 2x 8ohm c220 overlaping with c173n with some amps is not very easy load in higher bass lower midrange..

[Cousin Billy]

Thank you elviukai

I have a problem.

I already have the two pairs (four in total) of the Znom 6.0 ohm (Re 5.9 ohm) version of the C220-T6-220, 89.6dB.

I was going to run them in series?.

Remember please, I am running Atma-Sphere MA1 OTL tubed amplifiers (135 watts into 4 ohm, 140 watts into 8 ohms, 150 watts into 16 ohms). They like, and make more power, into higher impedence's. The higher the impedence, the better. No solid state amps in my house.

Do you have a solution to running these two drivers per speaker in series with the C173N-T6-90, 93.2 dB mids and the C25N-6-13 92dB tweeters?.

Do you recommend I send them back and get the 11 Ohm versions of this same driver?.

Should I wait and get the C220N-T6-220 Neodymium 93.2 dB woofers?.

I have not yet started cutting my MDF or Baltic Birch Ply. I can change the configuration of the box, i.e. volume. I can accomodate 3 C220's per box, what would my ideal volume be?.

Yes, my amps can drive 4 Ohms (3x 11 Ohms all in parallel), remember again, if I run three 11 ohm woofers in series, my amps will develop even more power.

Ultimately; for a tubed amplifier, do you recommend parallel, or series connection?.

What is the real problem with running woofers in series?. My amplifier manufacturer has told me there is nothing wrong with running drivers in series. Coincident Speaker Technologies run their Pure Reference Speakers with woofers in series.

LOL
Bill

[MJ Dijkstra]

Hi

The problem is there probably will be some differences between two identical woofers. If one woofer resonates at a slightly other freq, then it will have a different impedance plot. Putting in series will cause the voltage divide according to the impedance difference. The woofers will be differently loaded that case.
Parallel, they will not interact this way.

[elviukai]

Hi there,

if you have transformeless amps you would benefit from 16ohms. but you must understand one thing- midrange has eficienty of 92.5-95db you will not cach it up with 2x 8ohms in series. some people think that low sensitivity is only problem for low powered amps. high eficienty speakers(assuming the same xmax .cone and filter topology) sounds better -simply much more "imediatly sounding", lively at low levels, not compressed.luckily later production accuton is drivers did not add dicortion dramaticaly(comparing for example with audiotechnology) with increased input. I think you can use 2 woofers in series(just adapt xover for 16ohm impedance)
and lower midrange tweeter level by 3db(preferable not by voltage divider but by simple resitor in series with your amp) than tony design. so your speakers will be somewhere at 89db.
but still better would be 3x 16ohm with solid state which deliver more current in lower loads

and 4x 8 0hm in series paralel would be my choise for ordinary tube amp with 8ohm output
if you want i can provide some impedanse measurements and sensitivity for all versions i had designed.

another option is to use neodymium verison of c220. it has 2.5db more eficienty in lower midrange than ordinary c220. it would be very good driver because it has musch more sensitive lower midrange which is really issue in tony design. however i found prices of neodymium verison ridiculous, I always choose 2 std magnets versions for almost the same price. I also like to add extra magnet to c220.it provides 0.8-1.2db extra sensitivity in lower midrange and midrange(not in bass)

yes diferent impedanse profiles would split load inequaly but i didnt find that accutoin drivers suplied in pairs have sigificant diferencies(they have mostly the same peak height,only 2-3hz Fs differs sometimes)

one negative thing I noticed when conecting driver sin series- not good sonical result with high inductance(big gap) drivers. otherwise sonicaly diferencies very similar to paraleling

[crazyhub]

Warning!

C220NT6 will very probably not give you enough bass unless you run subwoofers like me. I have to cross them 65-70Hz 24db...otherwise I should apply high BSC and... then lose efficiency in the low-mid.

[elviukai]

yes. I run 8 scan speak 23w4557 subwoofers in array on good mood , but still its depends. I like listen music with subs off. sometimes i thinking to add extra 8psc c220 as subs to work up to 50hz . but speakers will be bulky even for my studio not speaking about home enviroment. for me most important range is 80-800hz . room resposne will boost midbass(especialy in smaller rooms) neodymium version has better sensitivity on lower midrange. for midbass c220is better, for lower midrange i like neodymium version litle bit more. but diferencies is minor.