Room response included in Xover design?

Hi to all,
I was looking to get opinions on should/could the room effect model be included with woofer low frequency response for xover design? Everything I see posted on this forum seems to exclude room effects. I realize if speaker was to be moved to different rooms that it would be best to not include the room effects. But, the speaker I’m currently designing will stay in one room for the foreseeable future.

Thanks in advance,
Rich
 

eriksquires

Member
2013-05-10 4:11 pm
I do. :) Works a treat, especially for 2 way speakers.

Here are some of the challenges and pro/cons, in my world.

There are complications in attempting quasi-anechoic measurements. In particular you still need to calculate the baffle step and add any port into the equation. Are you going to do that precisely correctly?

By relying on in-room for the mid-woofer, you skirt ALL of that, but you have to eyeball the mid-woofer/port response and look with rose colored glasses. It's going to look like hell, and if you are doing a 3-way, you can't really get a good enough measurement to get the right phase alignment. On the other hand, if you are doing a 2-way, can use gated / mixed measurements then you have it all done for you, and have a decent idea of how it will perform in a reasonably close room.

Here's a project I did that way, and you can see the fixes I've applied since:

A Speaker Maker's Journey: The SNR-1, Room Response and Roon


I designed that for an apartment I had 2 moves prior, still holds up. :)
 
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wintermute

Administrator
Paid Member
2003-08-03 11:43 am
Sydney
Unless you have a very large room and the speakers will be way away from any walls (in which case you can probably put full baffle step compensation into the crossover) you will need to take into consideration how the speaker will perform in the room if you are going to get the best result.

Now having said that you can choose to use EQ separate from your crossover to adjust for any room specific anomalies.

If you don't want to have any separate EQ then I would say yes you should consider the room effects when designing the crossover to get the best response for that room.

If you do want to use separate EQ and are likely to move the speakers to different rooms then I would say no you shouldn't design the crossover to take into account the room response.

Tony.
 
Hi to all,
I was looking to get opinions on should/could the room effect model be included with woofer low frequency response for xover design? Everything I see posted on this forum seems to exclude room effects. I realize if speaker was to be moved to different rooms that it would be best to not include the room effects. But, the speaker I’m currently designing will stay in one room for the foreseeable future.

Thanks in advance,
Rich


If your speaker has a uniform polar response, then it will sound good in any room.
See Toole YouTube
 
I design my speakers to match the room. It's one of the main advantages the diy speaker designer has.

What's the point is making a speaker with a theoretical ruler flat response if it's not going to be flat in room?

The downside is the speaker will only sound right in that room only. For most people that's not an issue.
 
@Zuhl: could you please elaborate how you design speakers to match the room?

First step, as normal, is get the normally measured raw 'in box' responses into x-sim and design the crossover to be flat. Then take measurements in room and adjust components to flatten the response.
My room has an uplift 400-600 hz which can affect vocals quite badly. Also a strong treble roll off. Easy to fix in the design. Cannot be fixed in a commercial speaker, other than by using an equaliser, which adds its own problems.

The only thing you can't fix are sharp dips. I have a narrow 'hole' at 50 hz not even an equaliser can fix.
 
Hi montana1, I agree that many loudspeaker designs (wrongly) don't consider how the loudspeaker(s) interact with the room. Many designs even neglect the baffle step, which makes things even worse. Apart from baffle step, you'll need to consider if your speaker will be set up stuffed into the corners of a room, to a rear wall, on the floor, or further into the room. There are a number of tools that allow you to estimate the "room gain" that you get from corner/near wall/on floor/whatever position for the bass response in the room.

However, in my opinion, these tools tend to overestimate the "room gain". As a rule of thumb I tend to design the bass alignment + xover filters such that a full 4pi system (i.e., zero room gain) is assumed if the speakers are set up at 1m or further away from any walls (which is mostly the case in my house).

For room effects at higher frequencies (i.e., everything except bass) there is only one "cure": waveguides help a great deal to focus the sound forward, where the listener typically is. This reduces the fraction of reflected "room" sound at the listener position.
 
@mbrennwa, Thanks so much for sharing your design ideas. I have been closely following your work on the Monkey Box thread. This speaker I’m currently building is also a Monkey coffin style 3way. I will post some pictures once it is completed. I still have one box remaining to finish shellac process. Should be completed in a couple weeks.

Best Regards,
Rich
 
@mbrennwa, I forgot to mention what an outstanding job you did on the ‘Monkey Box’!:D Your skill level is on a much higher plane than mine.:)I’m learning more with each speaker build. This is my 4th build and I can see progress is being made. I still have many questions to ask though.:D Thanks for your many contributions!

Best Regards,
Rich
 
I design my speakers to match the room. It's one of the main advantages the diy speaker designer has.

What's the point is making a speaker with a theoretical ruler flat response if it's not going to be flat in room?

The downside is the speaker will only sound right in that room only. For most people that's not an issue.


Making a speaker "flat" inside a room will not give a good result, it just sounds way to bright.

What you have to do is make it "flat" outside of a room, iow in an anechoic room. And make sure it has a uniform polar response.

Then above the Schroeder frequency the speaker will sound the same everywhere. Below the Schroeder frequency to about 100Hz, you can use room correction eq. And from 20-100Hz, you use multiple subs, iow the Geddes thingy..
This approach will give stunning results everywhere and has a huge listening sweet spot.