REW Testing For Speaker Design

[Kerr Forrest]

Hi,

I am a mechanical engineering student currently working on my Masters project to "design a loudspeaker for a specific listening environment" (my project brief). I plan to design a pair of bookshelf-style passive speakers to use with my amp and turntable set up in a room in my parents house. Because I will be designing the speakers specifically for the acoustics of that room I plan to start by using REW to gather information about the room's sonic characteristics and then work backwards by designing the speakers to hopefully complement the room acoustics as well as possible.

If anyone has any experience in using REW in a similar way (for speaker design rather than, say, working out where best to position existing speakers) I would love to hear your recommendations regarding which features of REW I should look into using and/or the kind of data which is most important for speaker design.

I am completely new to using REW, it was recommended to me by a friend, so I would also appreciate any resources you could point me to to get started.

Cheers,

Kerr.

 

[skid00]

Hi, Kerr.

I strongly recommend you download "room mode calculator". (https://www.harman.com/search-results?k=room+mode+calculator is the one I use.

That will tell you where you need to place the speakers for flattest response, and will give you the frequencies that are reinforced. You could then mod the subwoofer/woofer response.

 

[DanDan]

REW is pretty much a Laboratory. https://www.avnirvana.com/threads/some-guides-to-rew-and-acoustic-measurement.121/page-2#post-49827

 

[John Mulcahy]

VituixCAD is excellent for speaker design.

 

[DanDan]

Bookshelf speakers have some great possibilities. The original Hi Fi version of the NS10 sounded sweet when benefitting from the LF extension of the wall. The sealed Woofer is fast and has great LF extension.
I am a bit dubious about how much a passive design might be tweaked to compensate for room anomalies. By all means make the best speaker you can, availing of the the boundary reinforcement, but in most rooms there will be a strong long low mode. We easily filter these using High Q Eq to match the narrow mode. Passively?

 

[Kerr Forrest]

Bookshelf speakers have some great possibilities. The original Hi Fi version of the NS10 sounded sweet when benefitting from the LF extension of the wall. The sealed Woofer is fast and has great LF extension.
I am a bit dubious about how much a passive design might be tweaked to compensate for room anomalies. By all means make the best speaker you can, availing of the the boundary reinforcement, but in most rooms there will be a strong long low mode. We easily filter these using High Q Eq to match the narrow mode. Passively?

Hi Dan,

I see your point about how much scope there is to counteract the resonances in the room purely by design of passive speakers. My hope has been to design the cabinet and choose drivers such that any big peaks and troughs in frequency response of the room will be compensated; however, in all honesty I don't really know how possible that is likely to be yet.

I could consider powered speakers in order to allow in-built equalisation, however I have been reluctant to do this because of my lack of knowledge in amplification electronics and the extra work it would involve (I need to have my design more-or-less complete by the end of 2020). I may yet look into in-built amplification for the speakers, but I still need to figure out how much original designing I would need to do or whether I can mostly find existing components for my uni to accept it. Perhaps I could also consider electronic filters which come after the amp to reduce the power of the overly loud frequencies; this isn't a very efficient method but could maybe be justified for custom built speakers.

 

[DanDan]

I am not confident that your venture will satisfy your academic goals. DSP Controlled speakers are common now, many including measurement and adapting to the room.
Meyer used analogue filters to compensate for driver, cabinet, and crossover issues why back in their HD1 Studio Monitor.
MiniDSP have many interesting products for the DIYer..... https://www.minidsp.com/products/plate-amplifiers/pwr-ice125