Mp3 conversion - same quali, smaller size

[JazzMatazz]

Hi,
I would like to convert my mp3 collection to a different codec. I have 128 kbit/sec and 192kbit/sec files. Which codec(with bitrate) is smaller , but has the same quality as these two settings?
If it is possible, I would like to continue using DSP-Plug-ins like DFX. I noticed, that it´s supposrt for files varies from codec to codec.
Thankyou,
Jazz

[Spoon]

Re: Mp3 conversion - same quali, smaller size

Converting from a lossy format to a lossy format will only loose quality - you need to rip again from the original CD.