[woodgab]

Hi,

I'll just throw this out there.  Perhaps it's been asked before.  Maybe not.  Reading the 1801b heritage, I notice the first iteration had less baffle step compensation.  As my application puts the speakers in a wall, I was wondrin' if the lean mid-bass of the 1801a vs the wall boost of an infinite baffle (3-4db) would be sort of a wash?

I am not looking for dead on flat and am considering parametric EQ to get things right.

Thanks,
Chris

[David Ellis]

This is a very good question.

I believe there is some commentary regarding this, but I am not certain this specific situation has been addressed.

Your intuition is correct, and in theory the 1801a will work better when mounted in the wall.   The increased baffle step compensation of the 1801b will not be necessary and may in-fact drive the baffle step too rich (i.e. bass heavy).  

However, in most cases there is a bookshelf present.  This bookshelf is filled with "stuff" that will bounce & potentially absorb some of the low frequency.  In this regard, I think either crossover would be fine.  

Another matter to consider is the room construction.  Tall walls with thin sheetrock are very flexible and will soak considerable bass.  Concrete walls will bounce that bass energy.

Probably the most important concern in all of this is the port orientation.  If you are building an 1801 into a wall the port will go... into the wall.  I really don't recommend facing the port forward because is muddies the midrange.  Please read here for more information on this matter:

http://www.ellisaudio.com/porthole.htm

Given this, I recommend you build a sealed 1801.  This will roll off at 12db/octave at 50hz.  The cabinet is slighty smaller at @16-17 liters.  Dennis and I tested this a few years ago.  The results were acceptable, but neither Dennis or I preferred the sealed bass.  We both preferred the ported bass from the larger @22 liter ported 1801.

I have a couple dusty 1801a crossovers in the basement, but I'd have to check their condition before sending them to anyone.  I don't normally stock the 1801a crossover parts.  

Hopefully this addresses your concern.

Dave

[woodgab]

Thanks for the feedback, fine sir.

This would be a full flush inwall installation.  Rolloff beginning at 50Hz is fine with me.  Its good to hear you have some dusty crossovers left;)  I haven't finished the front soundstage of my HT and was recently impressed by some JM Labs products for their accuracy.  The dimensional factors I'm dealing with behind my walls spell three custom boxes and I think I'll be rolling my own, as a result.  The only consistency will be volume and baffle.

I have the ingredients to Dennis' OkaraOW1 at home and won't be finishing with that design because of a negative bass impression I got from some speakers that use the same 13cm mid-bass drivers.  I plan to sub, so ports would be stuffed, if found.  I have read your site about porting and would go further to say I don't care for porting of any kind, but I should emphasize I'm not an audiophile who has heard them all.

I like speakers that are highly resolved, even if it comes at the expense of being a bit thin.  I listen to amped Etymotic canal phones by day and have been fond of Magnapan and other ribbon products in the past.

Chris

[David Ellis]

I have read your site about porting and would go further to say I don't care for porting of any kind

I am on the fence in this regard.  There are some speakers that sound better with the port suffed and others that sound better with a port.  I think much of this depends on the sufficient low bass for the music material being applied.  

The other issue is how the port effects the cone travel of the driver.  The 1801 ported will actually have less cone travel than a sealed 1801 when used with 40hz bass & midrange too.   The port will actually restrict cone movement above the tuning frequency.  Below the tuning frequency (34hz for the 1801) the ported speaker will unload the driver.  Given pipe organ music the 1801 driver moves in & out freely.  I listen to a good choral Nativitiy piece with some pipe organ.  Some of those low notes are visibly below tuning frequency of the 1801.  Conversely, sealed cabients incurr greateter cone excursion "around" their tuning frequency, but as the frequency drops significant, the sealed cabinet with restrict cone movement.